Colon Cancer: Types, Risk Factors, Symptoms, Diagnosis, Staging and Treatment (2024)

James Van Der Beek of "Dawson's Creek" fame announced on November 3, 2024 that he had been diagnosed with colorectal cancer at age 47. He didn't give details of his prognosis but told People: "There's reason for optimism, and I'm feeling good."

In 2020, "Black Panther" actor Chadwick Boseman died of complications related to colon cancer at age 43, shocking fans, since he had received a stage-three diagnosis four years earlier, but never publicly spoken about the illness. His death was a pivotal moment in raising awareness of the rising number of younger people receiving a colorectal cancer diagnosis.

Whether you or a loved one are worried about getting colorectal cancer, have just been diagnosed, are going through colorectal cancer treatment, or are trying to stay well after treatment, this detailed information can help you find the answers you need.

What Is Colorectal Cancer?

Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.

Colorectal cancer has become increasingly common in younger people, with one in five cases now diagnosed in patients in their early 50s or younger, according to the American Cancer Society.

How does colorectal cancer start?

Polyps in the colon or rectum

Most colorectal cancers start as a growth on the inner lining of the colon or rectum. These growths are called polyps.

Polyps are quite common, especially as you get older. Most polyps are benign, or noncancerous. Some types of polyps can change into cancer over time (usually over many years). The chance of a polyp turning into cancer depends on the type of polyp it is. There are different types of polyps.

• Adenomatous polyps (adenomas): These polyps sometimes change into cancer. Because of this, adenomas are called a precancerous condition. The 3 types of adenomas are tubular, villous, and tubulovillous. Tubular adenomas are the most common type of adenomatous polyps. Villous adenomas are the least common type of adenomatous polyps, but are more likely to change into cancer.
• Hyperplastic polyps and inflammatory polyps: These polyps are more common, but in general they are not precancerous. Some people with large (more than 1cm) hyperplastic polyps might need colorectal cancer screening with colonoscopy more often.
• Sessile serrated polyps (SSP) and traditional serrated adenomas (TSA): These polyps are often treated like adenomas because they have a higher risk of changing into cancer.

Other factors that can make a polyp more likely to contain cancer or increase someone’s risk of developing colorectal cancer include:

• Size: If a polyp larger than 1 cm
• Number: If more than 3 polyps are found
• Histology: If dysplasia is seen in the polyp. Dysplasia means that the cells look abnormal, but they haven’t yet become cancer.

For more details on the types of polyps and conditions that can lead to colorectal cancer, see Your Colon or Rectal Pathology Report: Polyps.

How colorectal cancer spreads

If cancer forms in a polyp, it can grow into the wall of the colon or rectum over time. The wall of the colon and rectum is made up of many layers. Colorectal cancer starts in the innermost layer (the mucosa) and can grow outward through some or all of the other layers (see picture below).

When cancer cells are in the wall, they can then grow into blood vessels or lymph vessels (tiny channels that carry away waste and fluid). From there, they can travel to nearby lymph nodes or to distant parts of the body.

The stage (extent of spread) of a colorectal cancer depends on how deeply it grows into the wall and if it has spread outside the colon or rectum. For more on staging, see Colorectal Cancer Stages.

Types of cancer in the colon and rectum

Most colorectal cancers are adenocarcinomas. These cancers start in cells that make mucus to lubricate the inside of the colon and rectum. When doctors talk about colorectal cancer, they’re almost always talking about this type. Some subtypes of adenocarcinoma, such as signet ring and mucinous, may have a worse prognosis (outlook) than other subtypes of adenocarcinoma.

Other, much less common types of tumors can also start in the colon and rectum. These include:

• Carcinoid tumors. These start from special hormone-making cells in the intestine. See Gastrointestinal Carcinoid Tumors.
• Gastrointestinal stromal tumors (GISTs) start from nerve cells in the wall of the gastrointestinal tract. Some are benign (not cancer). These tumors are most commonly found in the stomach and small intestine. They are not commonly found in the colon or rectum.  See Gastrointestinal Stromal Tumor (GIST).
• Lymphomas are cancers of immune system cells. They mostly start in lymph nodes, but they can also start in the colon, rectum, or other organs. Information on lymphomas of the digestive system can be found in Non-Hodgkin Lymphoma.
• Sarcomas can start in blood vessels, muscle layers, or other connective tissues in the wall of the colon and rectum. Sarcomas of the colon or rectum are rare. See Soft Tissue Sarcoma.

Colon cancer diagnoses in young people are rising

"We know rates are increasing in young people, but it's alarming to see how rapidly the whole patient population is shifting younger, despite shrinking numbers in the overall population," Rebecca Siegel, senior scientific director at the American Cancer Society, and lead author of a report published in 2023, said in a press release. "The trend toward more advanced disease in people of all ages is also surprising and should motivate everyone 45 and older to get screened."

The researchers also found that more people are being diagnosed with late stages of the disease; 60% of cases were found to have spread to other regions of the body in 2019, up from 52% in the mid-2000s.

The report added to previous research over the past three decades that suggests rising rates of colon cancer and related illnesses like rectal cancer among younger people.If caught early, colon cancer is very treatable, and the five-year relative survival rate is about 90% if the cancer doesn't spread, according to the American Cancer Society. 

Bowel cancers can be difficult to diagnose because the symptoms — such as abdominal pain, constipation, diarrhea, weight loss, and fatigue — are common with ailments like hemorrhoids, inflammatory bowel disease, or irritable bowel syndrome. What's more, routine testing isn't offered to many people under 50 in several countries, including the US.

But it's common for people to have no symptoms until the later stages of the illness. That's why it's important to get screened regularly, especially if you have risk factors.

Colorectal Cancer Risk Factors

Researchers have found several risk factors that might increase a person’s chance of developing colorectal polyps or colorectal cancer.

Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history of cancer, can’t be changed.

But having a risk factor, or even many, does not mean that you will get the disease. And some people who get the disease may not have any known risk factors.

Colorectal Cancer Risk factors you can change

Many lifestyle-related factors have been linked to colorectal cancer. In fact, more than half of all colorectal cancers are linked to risk factors that can be changed.

Being overweight or obese

If you are overweight or obese (very overweight), your risk of developing and dying from colorectal cancer is higher. Being overweight raises the risk of colorectal cancer in people, but the link seems to be stronger in men. Getting to and staying at a healthy weight may help lower your risk.

Diabetes mellitus, Type 2

People with type 2 diabetes mellitus are more likely than people who don’t to develop colorectal cancer. Researchers suspect that this higher risk may be due to high levels of insulin in people with diabetes mellitus. Both type 2 diabetes and colorectal cancer share some of the same risk factors (such as being overweight and physical inactivity). But even after taking these factors into account, people with type 2 diabetes still have an increased risk. They also tend to have a less favorable prognosis (outlook) after diagnosis.

Certain types of diets

A long-term diet that's high in red meats (such as beef, pork, lamb, or liver) and processed meats (like hot dogs and some lunch meats) raises your colorectal cancer risk.

Cooking meats at very high temperatures (frying, broiling, or grilling) creates chemicals that might raise your cancer risk.

Having a low blood level of vitamin D may also increase your risk.

Following a healthy eating pattern that includes plenty of fruits, vegetables, and whole grains, and that limits or avoids red and processed meats and sugary drinks probably lowers risk.

Smoking

People who have smoked tobacco for a long time are more likely to develop and die from colorectal cancer than people who don't smoke. Smoking tobacco also increases the risk for people to develop colon polyps. Smoking is a well-known cause of lung cancer, but it's linked to a lot of other cancers, too. If you smoke and want to know more about quitting, see How to Quit Using Tobacco.

Alcohol use

Colorectal cancer has been linked to moderate to heavy alcohol use. Even light-to-moderate alcohol intake has been associated with some risk. It is best not to drink alcohol. If people do drink alcohol, they should have no more than 2 drinks a day for men and 1 drink a day for women. This could have many health benefits, including a lower risk of many kinds of cancer.

Colorectal Cancer Risk factors you cannot change

Your age

Your risk of colorectal cancer goes up as you age. Younger adults can get it, but it’s much more common after age 50. Colorectal cancer is rising among people who are younger than age 50, and the reason for this remains unclear.

Your racial and ethnic background

American Indian and Alaska Native people have the highest rates of colorectal cancer in the United States, followed by African American men and women.

Jews of Eastern European descent (Ashkenazi Jews) have one of the highest colorectal cancer risks of any ethnic group in the world.

Your sex at birth

Men who have colorectal cancer are more likely to die from it than women. The reasons are not fully clear. Women who have colorectal cancer are more likely to have right-sided colon cancer, particularly if they are no longer menstruating (postmenopausal).

Cholecystectomy

People who have had their gallbladder removed (cholecystectomy) have been found to have a mildly higher risk for right-sided colon cancer. It’s not fully understood why this is. Research is ongoing.

A personal history of colorectal polyps or colorectal cancer

If you have a history of adenomatous polyps (adenomas), you are at increased risk of developing colorectal cancer. This is especially true if the polyps are large, if there are many of them, or if any of them show dysplasia.

If you’ve had colorectal cancer, even though it was completely removed, you are more likely to develop new cancers in other parts of the colon and rectum. The chances of this happening are greater if you had your first colorectal cancer when you were younger.

A personal history of inflammatory bowel disease

If you have inflammatory bowel disease (IBD), including either ulcerative colitis or Crohn’s disease, your risk of colorectal cancer is increased.

IBD is a condition in which the colon is inflamed over a long period of time. People who have had IBD for many years, especially if untreated, often develop dysplasia. Dysplasia is a term used to describe cells in the lining of the colon or rectum that look abnormal, but are not cancer cells. They can change into cancer over time.

If you have IBD, you may need to start getting screened for colorectal cancer when you are younger and be screened more often.

Inflammatory bowel disease is different from irritable bowel syndrome (IBS), which does not appear to increase your risk for colorectal cancer.

A personal history of radiation to the abdomen or pelvis area

If you survived cancer in the past and as part of your treatment, received radiation to the area where your colon is (abdomen and pelvis area), your risk of colorectal cancer is increased. If you have received radiation to the abdomen or pelvis, especially as a child, you may need to start getting screened for colorectal cancer when you are younger and be screened more often.

Several studies suggest that men who had radiation therapy to treat prostate cancer might have a higher risk of rectal cancer because the rectum receives some radiation during treatment. Most of these studies are based on men treated in the 1980s and 1990s, when radiation treatments were less precise than they are today. The effect of more modern radiation methods on rectal cancer risk is not clear, but research continues to be done in this area.

A family history of colorectal cancer or adenomatous polyps

Most colorectal cancers are found in people without a family history of colorectal cancer. Still, as many as 1 in 3 people who develop colorectal cancer have other family members who have had it.

People with a history of colorectal cancer in a first-degree relative (parent, sibling, or child) are at increased risk. The risk is even higher if that relative was diagnosed with cancer when they were younger than age 50, or if more than one first-degree relative is affected.

The reasons for the increased risk are not clear in all cases. Cancers can “run in the family” because of inherited genes, shared environmental factors, or some combination of these.

Having family members who have had adenomatous polyps is also linked to a higher risk of colon cancer. (Adenomatous polyps are the kind of polyps that can become cancer.)

If you have a family history of adenomatous polyps or colorectal cancer, talk with your doctor about the possible need to start screening at a younger age. If you've had adenomatous polyps or colorectal cancer, it’s important to tell your close relatives so that they can pass along that information to their doctors and start screening at the right age.

Having an inherited syndrome

About 5% of people who develop colorectal cancer have inherited gene changes (mutations) that cause family cancer syndromes and can lead to them getting the disease.

The most common inherited syndromes linked with colorectal cancers are Lynch syndrome (hereditary non-polyposis colorectal cancer, or HNPCC) and familial adenomatous polyposis (FAP), but other rarer syndromes can increase colorectal cancer risk, too.

Lynch syndrome (hereditary non-polyposis colon cancer or HNPCC)

Lynch syndrome is the most common hereditary colorectal cancer syndrome. It accounts for about 2% to 4% of all colorectal cancers. In most cases, this disorder is caused by an inherited defect in either the MLH1, MSH2,MSH6, PMS2, or EPCAM gene, but changes in other genes can also cause Lynch syndrome. These genes, called DNA mismatch repair (MMR) genes, normally help repair DNA that has been damaged.

The cancers linked to this syndrome tend to develop when people are relatively young and tend to develop right-sided colon cancer. People with Lynch syndrome can have polyps, but they tend to have only a few. The lifetime risk of colorectal cancer in people with this condition may be as high as 50%, but this depends on which gene is affected.

Women with this condition also have a very high risk of developing cancer of the endometrium (lining of the uterus). Other cancers linked with Lynch syndrome include cancer of the ovary, stomach, small intestine, pancreas, kidney, prostate, breast, ureters (tubes that carry urine from the kidneys to the bladder), and bile duct. People with Turcot syndrome (a rare inherited condition) who have a defect in one of the Lynch syndrome genes are at a higher risk of colorectal cancer as well as a specific type of brain cancer called glioblastoma.  

For more on Lynch syndrome, see What Causes Colorectal Cancer?, Can Colorectal Cancer Be Prevented?, and Family Cancer Syndromes.

Familial adenomatous polyposis (FAP)

FAP is caused by changes (mutations) in the APC gene that a person inherits from their parents. About 1% of all colorectal cancers are caused by FAP.

In the most common type of FAP, hundreds or thousands of polyps develop in a person’s colon and rectum, often starting at ages 10 to 12. Cancer usually develops in 1 or more of these polyps as early as age 20. By age 40, almost all people with FAP will have colon cancer if their colon hasn’t been removed to prevent it. People with FAP also have an increased risk for cancers of the stomach, small intestines, pancreas, liver, and some other organs.

There are 3 sub-types of FAP:

• In attenuated FAP or AFAP, patients have fewer polyps (less than 100), and colorectal cancer tends to occur at a later age (40s and 50s).
• Gardner syndrome is a type of FAP that also causes noncancerous tumors of the skin, soft tissue, and bones.
• In Turcot syndrome, people who have APC gene mutation are at a high risk of having many adenomatous polyps and colorectal cancer, but also a specific type of brain cancer called medulloblastoma.

Rare inherited conditions linked to colorectal cancer

• Peutz-Jeghers syndrome (PJS): People with this inherited condition tend to have freckles around the mouth (and sometimes on their hands and feet) and a special type of polyp called hamartomas in their digestive tract. These people are at a much higher risk for colorectal cancer, as well as other cancers, such as cancers of the breast, ovary, and pancreas. They usually are diagnosed at a younger than usual age. This syndrome is caused by mutations in the STK11 (LKB1) gene.
• MUTYH-associated polyposis (MAP): People with this syndrome develop many colon polyps. These tend to become cancer if not watched closely with routine colonoscopies. These people also have an increased risk of other cancers of the GI (gastrointestinal) tract, breast, ovary, bladder, and thyroid. This syndrome is caused by mutations in the MUTYH gene (which is involved in “proofreading” the DNA and fixing any mistakes) and often leads to cancer at a younger age.
• Cystic fibrosis (CF): CF is an inherited condition in which the cells in some body organs make mucus that is thicker and stickier than normal. This can lead to health problems, especially in the lungs and pancreas. As better medical care has helped people with CF live longer, it’s become clear that people with CF are also at increased risk for colorectal cancer, which usually occurs at a much earlier age than in people without the condition. The risk for colorectal cancer is even higher in people who have had an organ transplant, such as a lung transplant. CF is caused by mutations in the CFTR gene.

Since many of these syndromes are linked to colorectal cancer at a young age and other types of cancer, identifying families with these inherited syndromes is important. It lets doctors recommend specific steps such as screening and other preventive measures when the person is younger. Information on risk assessment, and genetic counseling and testing for many of these syndromes can be found in Genetic Testing, Screening, and Prevention for People with a Strong Family History of Colorectal Cancer.

Can Colorectal Cancer Be Prevented?

There’s no sure way to prevent colorectal cancer, but screening can find abnormal cells before they become cancer. You might also be able to lower your risk for colorectal cancer by changing the risk factors that you can control.

Colorectal cancer screening

Screening is the process of looking for cancer or precancer in people who have no symptoms of the disease. Regular colorectal cancer screening is one of the most powerful tools for preventing colorectal cancer.

From the time the first abnormal cells start to grow into polyps, it usually takes about 10 to 15 years for them to develop into colorectal cancer. With regular screening, most polyps can be found and removed before they have the chance to turn into cancer. Screening can also find colorectal cancer early, when it’s small, hasn’t spread, and might beeasier to treat.

If you’re age 45 or older, you should start getting screened for colorectal cancer. Several types of tests can be used. Talk to your health care provider about which ones might be good options for you. No matter which test you choose, the most important thing is to get tested.

If you have a strong family history of colorectal polyps or cancer, talk with your doctor about your risk. You might benefit from genetic counseling to review your family medical tree to see how likely it is that you have a family cancer syndrome.

Body weight, physical activity, and diet

You might be able to lower your risk of colorectal cancer by managing your diet and physical activity.

Weight: Being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Staying at a healthy weight may help lower your risk.

Physical activity: Being more active lowers your risk of colorectal cancer and polyps. Regular moderate to vigorous activity can lower the risk. Increasing the amount and intensity of your physical activity may help reduce your risk.

Diet: Overall, diets that are high in vegetables, fruits, and whole grains, and low in red and processed meats, probably lower colorectal cancer risk, although it’s not exactly clear which factors are important. Many studies have found a link between red meats (beef, pork, and lamb) or processed meats (such as hot dogs, sausage, and lunch meats) and increased colorectal cancer risk.

In recent years, some large studies have shown conflicting evidence that fiber in the diet lowers colorectal cancer risk. Research in this area is still under way.

Limiting red and processed meats and eating more vegetables, fruits, and whole grains may help lower your risk.

For more information about diet, see Colorectal Cancer and Diet: Studies Shows Dietary Changes Can Shrink Tumors.

Alcohol: Several studies have found a higher risk of colorectal cancer with increased alcohol intake, especially among men. It is best not to drink alcohol. For people who do drink, they should have no more than 1 drink per day for women or two drinks per day for men. Not drinking alcohol may help reduce your risk.

For more information about diet and physical activity, see the American Cancer Society Guidelines for Diet and Physical Activity for Cancer Prevention.

Quitting smoking

Long-term smoking is linked to an increased risk of colorectal cancer, as well as many other cancers and health problems. Quitting smoking may help lower you risk of colorectal cancer and many other types of cancer, too. If you smoke and would like help quitting, call the American Cancer Society at 1-800-227-2345.

Vitamins, calcium, and magnesium

Some studies suggest that taking a daily multivitamin containing folic acid may lower colorectal cancer risk, but not all studies have found this. In fact, some studies have hinted that folic acid might help existing tumors grow. More research is needed in this area.

Some studies have suggested that vitamin D, which you can get from sun exposure, in certain foods, or in a vitamin pill, might lower colorectal cancer risk. Studies have shown that low vitamin D levels are associated with an increased risk of colorectal cancer, as well as other cancers. Because of concerns that excess sun exposure can cause skin cancer, most experts do not recommend this as a way to lower colorectal cancer risk at this time. More studies are needed to determine if increasing vitamin D intake from a supplement can help prevent colorectal cancer. It is best to talk with your doctor about whether your vitamin D level should be tested.

Low levels of dietary calcium have been linked with an increased risk of colorectal cancer in some studies. Others suggest that increasing calcium intake may lower the risk for the recurrence of colorectal adenomas. Calcium is important for a number of health reasons aside from possible effects on cancer risk. But because of the possible increased risk of prostate cancer in men with high calcium/dairy product intake, and the possible lower risk of other cancers like colorectal cancer and breast cancer, the American Cancer Society does not have any specific recommendations regarding dairy food consumption for cancer prevention.

Calcium and vitamin D might work together to reduce colorectal cancer risk, as vitamin D aids in the body’s absorption of calcium. Still, not all studies have found that supplements of these nutrients reduce risk.

A few studies have found a possible link between a diet that’s high in magnesium and reduced colorectal cancer risk, especially among women. More research is needed to determine if this link exists.

Nonsteroidal anti-inflammatory drugs (NSAIDs)

Many studies have found that people who regularly take aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin, Advil) and naproxen (Aleve), have a lower risk of colorectal cancer and polyps.

But aspirin and other NSAIDs can cause serious or even life-threatening side effects, such as bleeding from stomach irritation or stomach ulcers, which may outweigh the benefits of these medicines for the general public. For this reason, the American Cancer Society does not recommend taking NSAIDs just to lower colorectal cancer risk if you are at average risk.

Still, for some people in their 50s who have a high risk of heart disease, where low-dose aspirin is found to be beneficial, the aspirin may also have the added benefit of reducing the risk of colorectal cancer.

Because aspirin or other NSAIDs can have serious side effects, check with your doctor before starting any of them on a regular basis.

Hormone replacement therapy for women

Some studies have shown that taking estrogen and progesterone after menopause (sometimes called menopausal hormone therapy or combined hormone replacement therapy) may reduce a woman’s risk of developing colorectal cancer, but other studies have not.

Because taking estrogen and progesterone after menopause can also increase a woman’s risk of heart disease, blood clots, and cancers of the breast and lung, it’s not commonly recommended just to lower colorectal cancer risk.

If you’re considering using menopausal hormone therapy, be sure to discuss the risks and benefits with your doctor.

Colorectal Cancer Early Detection, Diagnosis, and Staging

Know the signs and symptoms of colorectal cancer. Find out how colorectal cancer is tested for, diagnosed, and staged.

American Cancer Society Guideline for Colorectal Cancer Screening

The American Cancer Society has developed colorectal cancer screening guidelines for people at average risk as well people at high risk for colorectal cancer.

Test options for colorectal cancer screening

Several test options are available for colorectal cancer screening:

Stool-based tests

• Highly sensitive fecal immunochemical test (FIT) every year
• Highly sensitive guaiac-based fecal occult blood test (gFOBT) every year
• Multi-targeted stool DNA test with fecal immunochemical testing (MT-sDNA or sDNA-FIT or FIT-DNA)) every 3 years

Visual (structural) exams of the colon and rectum

• Colonoscopy every 10 years
• CT colonography (virtual colonoscopy) every 5 years
• Sigmoidoscopy every 5 years

There are some differences between these tests to consider (see Colorectal Cancer Screening Tests), but the most important thing is to get screened, no matter which test you choose. Talk to your health care provider about which tests might be good options for you, and to your insurance provider about your coverage.

If a person chooses to be screened with a test other than colonoscopy, any abnormal test result should be followed up with a timely colonoscopy.

For people at increased or high risk

People at increased or high risk of colorectal cancer might need to start colorectal cancer screening before age 45, be screened more often, and/or get specific tests. This includes people with:

• A strong family history of colorectal cancer or certain types of polyps (see Colorectal Cancer Risk Factors)
• A personal history of colorectal cancer or certain types of polyps
• A personal history of inflammatory bowel disease (ulcerative colitis or Crohn’s disease)
• A known family history of a hereditary colorectal cancer syndrome, such as familial adenomatous polyposis (FAP) or Lynch syndrome (also known as hereditary non-polyposis colon cancer or HNPCC)
• A personal history of radiation to the abdomen (belly) or pelvic area to treat a prior cancer

The American Cancer Society does not have screening guidelines specifically for people at increased or high risk of colorectal cancer. However, other professional medical organizations, such as the US Multi-Society Task Force on Colorectal Cancer (USMSTF), do put out such guidelines. These guidelines are complex and are best reviewed with your health care provider. In general, these guidelines put people into several groups (although the details depend on each person’s specific risk factors).

People at increased risk for colorectal cancer

People with one or more family members who have had colon or rectal cancer

Screening recommendations for these people depend on who in the family had cancer and how old they were when it was diagnosed. Some people with a family history will be able to follow the recommendations for average-risk adults, but others might need to get a colonoscopy (and not any other type of test) more often, and possibly starting before age 45.

People who have had certain types of polyps removed during a colonoscopy

Most of these people will need to get a colonoscopy again after 3 years, but some people might need to get one earlier (or later) than 3 years, depending on the type, size, and number of polyps.

People who have had colon or rectal cancer

Most of these people will need to start having colonoscopies regularly about 1 year after surgery to remove the cancer. Other procedures like MRI or proctoscopy with ultrasound might also be recommended for some people with rectal cancer, depending on the type of surgery they had.

People who have had radiation to the abdomen (belly) or pelvic area to treat a prior cancer

Most of these people will need to start having colorectal screening (colonoscopy or stool-based testing) at an earlier age (depending on how old they were when they got the radiation). Screening often begins 10 years after the radiation was given or at age 35, whichever comes last. These people might also need to be screened more often than normal (such as at least every 3 to 5 years).

People at high risk for colorectal cancer

People with inflammatory bowel disease (Crohn’s disease or ulcerative colitis)

These people generally need to get colonoscopies (not any other type of test) starting at least 8 years after they are diagnosed with inflammatory bowel disease. Follow-up colonoscopies should be done every 1 to 3 years, depending on the person’s risk factors for colorectal cancer and the findings on the previous colonoscopy.

People known or suspected to have certain genetic syndromes

These people generally need to have colonoscopies (not any other tests). Screening is often recommended to begin at a young age, possibly as early as the teenage years for some syndromes – and needs to be done much more frequently. Specifics depend on which genetic syndrome you have and other factors.

If you’re at increased or high risk of colorectal cancer (or think you might be), talk to your health care provider to learn more. They can suggest the best screening option for you, as well as determine what type of screening schedule you should follow, based on your individual risk.

For more information about colonoscopy, see our 4 part series: The Truth about Colonoscopy.

Colorectal Cancer Signs and Symptoms

Colorectal cancer might not cause symptoms right away, but if it does, it may cause one or more of these symptoms.

Common signs and symptoms of colorectal cancer

• A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days
• A feeling that you need to have a bowel movement that’s not relieved by having one
• Rectal bleeding with bright red blood
• Blood in the stool, which might make the stool look dark brown or black
• Cramping or abdominal (belly) pain
• Weakness and fatigue
• Unintended weight loss

Colorectal cancers can often bleed into the digestive tract. Sometimes the blood can be seen in the stool or make it look darker, but often the stool looks normal. But over time, the blood loss can build up and can lead to low red blood cell counts (anemia). Sometimes the first sign of colorectal cancer is a blood test showing a low red blood cell count.

Signs of colorectal cancer that has spread

Some people may have signs that the cancer has spread to the liver with a large liver felt on exam, jaundice (yellowing of the skin or whites of the eyes), or trouble breathing from cancer spread to the lungs.  

Do colon polyps cause symptoms?

Most people with polyps will not have any symptoms. However, some people may have symptoms from polyps, such as:

• Bleeding from the rectum
• Change in stool color, either red or black
• Change in bowel movement, either prolonged constipation or diarrhea
• Low red blood cell count due to low iron (iron deficiency anemia)
• Abdominal (belly) pain

These symptoms can also be due to other causes, such as foods, medicines, or other medical conditions. If these symptoms are present, you should discuss further with your doctor.

If you have signs or symptoms

Many of these symptoms can be caused by conditions other than colorectal cancer, such as infection, hemorrhoids, or irritable bowel syndrome. Still, if you have any of these problems, it’s important to see your doctor right away so the cause can be found and treated, if needed. See Tests to Diagnose Colorectal Cancer.

Colorectal Cancer Stages

After someone is diagnosed with colorectal cancer, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer's stage when talking about survival statistics.

The earliest stage of colorectal cancers is called stage 0 (a very early cancer), and then range from stages I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage. Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

The staging system most often used for colorectal cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information: 

• The extent (size) of the tumor (T): How far has the cancer grown into the wall of the colon or rectum? These layers, from the inner to the outer, include:
• The inner lining (mucosa), which is the layer in which nearly all colorectal cancers start. This includes a thin muscle layer (muscularis mucosa).
• The fibrous tissue beneath this muscle layer (submucosa)
• A thick muscle layer (muscularis propria)
• The thin, outermost layers of connective tissue (subserosa and serosa) that cover most of the colon but not the rectum 
•  The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes?
• The spread (metastasis) to distant sites (M): Has the cancer spread to distant lymph nodes or distant organs such as the liver or lungs?

The system described below is the most recent AJCC system effective January 2018. It uses the pathologic stage (also called the surgical stage), which is determined by examining tissue removed during an operation. This is also known as surgical staging. This is likely to be more accurate than clinical staging, which takes into account the results of a physical exam, biopsies, and imaging tests, done before surgery.

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more information, see Cancer Staging.

Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.

* The following additional categories are not listed in the table above:

• TX: Main tumor cannot be assessed due to lack of information.
• T0: No evidence of a primary tumor.
• NX: Regional lymph nodes cannot be assessed due to lack of information.

Colon-cancer treatment

If you’ve been diagnosed with colorectal cancer, your cancer care team will discuss your treatment options with you. It’s important that you think carefully about each of your choices. Weigh the benefits of each treatment option against the possible risks and side effects.

Surgery for Colon Cancer

Surgery is often the main treatment for early-stage colon cancers. The type of surgery used depends on the stage (extent) of the cancer, where it is in the colon, and the goal of the surgery.

Any type of colon surgery needs to be done on a clean and empty colon. You will be put on a special diet before surgery and may need to use laxative drinks and/or enemas to get all of the stool out of your colon. This bowel prep is a lot like the one used before a colonoscopy.

Polypectomy and local excision

Some early colon cancers (stage 0 and some early-stage I tumors) and most polyps can be removed during a colonoscopy. This is a procedure that uses a long, flexible tube with a small video camera on the end that’s put into the person’s rectum and eased into the colon. These surgeries can be done during a colonoscopy:

• For a polypectomy, the cancer is removed as part of the polyp, which is cut at its base (the part that looks like the stem of a mushroom). This is usually done by passing a wire loop through the colonoscope to cut the polyp off the wall of the colon with an electric current.
• A local excision is a slightly more involved procedure. Tools are used through the colonoscope to remove small cancers on the inside lining of the colon, along with a small amount of surrounding healthy tissue on the wall of colon.

When cancer or polyps are taken out this way, the doctor doesn’t have to cut into the abdomen (belly) from the outside. The goal of either of these procedures is to remove the tumor in one piece. If some cancer is left behind or if, based on lab tests, the tumor is thought to have a chance to spread, a type of colectomy (see below) might be the next surgery.

Colectomy

A colectomy is surgery to remove all or part of the colon. Nearby lymph nodes are also removed.

• If only part of the colon is removed, it's called a hemicolectomy, partial colectomy, or segmental resection. The surgeon takes out the part of the colon with the cancer and a small segment of normal colon on either side. Usually, about one-fourth to one-third of the colon is removed, depending on the size and location of the cancer. The remaining sections of colon are then reattached. At least 12 nearby lymph nodes are also removed so they can be checked for cancer.
• If all of the colon is removed, it's called a total colectomy. Total colectomy isn’t often needed to remove colon cancer. It’s mostly used only if there's another problem in the part of the colon without cancer, such as hundreds of polyps (in someone with familial adenomatous polyposis) or, sometimes, inflammatory bowel disease.

How colectomy is done

A colectomy can be done in 2 ways:

• Open colectomy: The surgery is done through a single long incision (cut) in the abdomen (belly).
• Laparoscopic-assisted colectomy: The surgery is done through many smaller incisions and special tools. A laparoscope is a long, thin lighted tube with a small camera and light on the end that lets the surgeon see inside the abdomen. It’s put into one of the small cuts, and long, thin instruments are put in through the others to remove part of the colon and lymph nodes.

Because the incisions are smaller in a laparoscopic-assisted colectomy than in an open colectomy, patients often recover faster and may be able to leave the hospital sooner than they would after an open colectomy. This type of surgery requires special expertise. If you're considering this type of surgery, be sure to look for a skilled surgeon who has done many of these operations.

Overall survival rates and the chance of the cancer returning are much the same between an open colectomy and a laparoscopic-assisted colectomy.

If the colon is blocked

When cancer blocks the colon, it usually happens slowly, and the person can become very sick over time. In cases like these, if the person is strong enough to tolerate surgery and the colon cancer is felt to be curable, it is generally recommended that they undergo surgery to remove the tumor and treat the blockage. If the person is not strong enough to undergo colon surgery or their colon cancer is not curable, a stent may be placed to treat the blockage. A stent is a hollow, expandable metal tube that the doctor can put inside the colon and through the small opening using a colonoscope. This tube keeps the colon open and relieves the blockage.

If a stent can’t be placed in a blocked colon or if the tumor has caused a hole in the colon, surgery may be needed right away. This usually is the same type of colectomy that’s done to remove the cancer, but instead of reconnecting the ends of the colon, the top end of the colon is attached to an opening (called a stoma) made in the skin of the abdomen. Stool then comes out of this opening. This is called a colostomy and is usually only needed for a short time. Sometimes the end of the small intestine (the ileum) instead of the colon is connected to a stoma in the skin. This is called an ileostomy. Either way, a bag sticks to the skin around the stoma to hold the stool.

Once the patient is healthier, another operation (known as a colostomy reversal or ileostomy reversal) can be done to put the ends of the colon back together or to attach the ileum to the colon. It might take anywhere from 2 to 6 months after the ostomy was first made for this reversal surgery to be done due to healing times or even the need to treat with chemotherapy. Sometimes, if a tumor can’t be removed or a stent placed, the colostomy or ileostomy may need to be permanent.

Colostomy or ileostomy

Some people may need a temporary or permanent colostomy (or ileostomy) after surgery. This can take some time to get used to and might require some lifestyle adjustments. If you have a colostomy or ileostomy, you’ll need help to learn how and where to order the proper supplies and how to manage it. Specially trained ostomy nurses or enterostomal therapists can help. They’ll usually see you in the hospital before your operation to discuss the ostomy and to mark a site for the opening. After the operation, they may come to your home or meet with you in an outpatient setting to give you more training. There may also be ostomy support groups you can be part of. This is a good way to learn from people with experience in managing this part of the treatment.

For more information, see Colostomy Guide and Ileostomy Guide.

Surgery for colon cancer spread

If the cancer has spread to only one or a few spots (nodules) in the lungs or liver (and apparently nowhere else), surgery may be used to remove it. In most cases, this is only done if the cancer in the colon is also being removed (or was already removed). Depending on the extent of the cancer, this might help the patient live longer, or it could even cure the cancer. Deciding if surgery is an option to remove areas of cancer spread depends on their size, number, and location.

Possible side effects of colon surgery

Possible risks and side effects of surgery depend on several factors, including the extent of the operation and your general health before surgery. Problems during or shortly after the operation can include bleeding, infection, and blood clots in the legs.

When you wake up after surgery, you will have some pain and will need pain medicines for a few days. For the first couple of days, you may not be able to eat, or you may be allowed limited liquids, as the colon needs some time to recover. Most people are able to eat solid food in a few days.

Sometimes after colon surgery, the bowel takes longer than normal to “wake up” and start working again. This is called an ileus. It might be caused by the anesthesia or the actual handling of the bowel during the operation. Sometimes, too much pain medicine after the surgery can slow down the bowel function. If you develop an ileus, your doctor may want to delay eating solid food or even liquids, especially if you are having nausea and/or vomiting. More tests might also be done to make sure that the situation is not more serious.

Rarely, the new connections between the ends of the colon may not hold together and may leak. This can quickly cause severe pain, fever, and the belly to feel very hard. A smaller leak may cause you to not pass stool, have no desire to eat, and not do well or recover after surgery. A leak can lead to infection, and more surgery may be needed to fix it. It’s also possible that the incision (cut) in the abdomen (belly) might open up, becoming an open wound that may need special care as it heals.

After the surgery, you might develop scar tissue in your abdomen that can cause organs or tissues to stick together. These are called adhesions. Normally, your intestines freely slide around inside your belly. In rare cases, adhesions can cause the bowels to twist up and can even block the bowel. This causes pain and swelling in the belly that’s often worse after eating. Further surgery may be needed to remove the scar tissue.

Related: Best Alternatives to Cancer Treatment

Radiation Therapy for Colorectal Cancer

Radiation therapy is a treatment using high-energy rays (such as x-rays) or particles to destroy cancer cells. It is more often used to treat rectal cancer than colon cancer. For some colon and rectal cancers, treating with chemotherapy at the same time can make radiation therapy work better. Using these 2 treatments together is called chemoradiation.

Radiation therapy for colon cancer

It's not common to use radiation therapy to treat colon cancer, but it may be used in certain cases:

• Before surgery (along with chemo) to help shrink a tumor and make it easier to remove.
• After surgery, if the cancer has attached to an internal organ or the lining of the belly (abdomen). If this happens, the surgeon can’t be sure that all of the cancer has been removed. Radiation therapy may be used to try to kill any cancer cells that may have been left behind.
• During surgery, right to the area where the cancer was, to kill any cancer cells that may be left behind. This is called intraoperative radiation therapy or IORT.
• Along with chemo to help control cancer if a person is not healthy enough for surgery.
• To ease symptoms if advanced colon cancer is causing intestinal blockage, bleeding, or pain.
• To help treat colon cancer that has spread to other areas, such as the bones, lungs, or brain.

Radiation therapy for rectal cancer

For rectal cancer, radiation therapy is a more common treatment and may be used:

• Either before and/or after surgery, often along with chemotherapy, to help keep the cancer from coming back. Many doctors now favor giving radiation therapy before surgery, as it may make it easier to remove the cancer, especially if the cancer's size and/or location might make surgery difficult. This is called neoadjuvant treatment. Giving chemoradiation before surgery can also help lower the chances of damaging the sphincter muscles in the rectum when surgery is done. In either case, nearby lymph nodes are usually treated too.
• During surgery, right to the area where the tumor was, to kill any rectal cancer cells that may be left behind. This is called intraoperative radiation therapy or IORT.
• With or without chemo to help control rectal cancer if a person is not healthy enough for surgery or to ease symptoms if advanced rectal cancer is causing intestinal blockage, bleeding, or pain.
• To re-treat rectal tumors that come back in the pelvis after radiation was given.
• To help treat rectal cancer that has spread to other areas, such as the bones, lungs, or brain.

Types of radiation therapy

Different types of radiation therapy can be used to treat colon and rectal cancers.

External-beam radiation therapy (EBRT)

EBRT is the type of radiation therapy used most often for people with colon or rectal cancer. The radiation is focused on the cancer from a machine outside the body. It’s a lot like getting an x-ray, but the radiation is more intense. How often and how long a person gets radiation treatments depends on the reason the radiation is being given and other factors. Treatments might be given over the course of a few days or several weeks.

Newer EBRT techniques, such as three-dimensional conformal radiation therapy (3D-CRT), intensity modulated radiation therapy (IMRT), and stereotactic body radiation therapy (SBRT), have been shown to help doctors treat colorectal cancers that have spread to the lungs or liver more accurately while lowering the radiation exposure to nearby healthy tissues. They are typically used if there are only a small number of tumors and if the tumors are causing symptoms and surgery is not an option.

Internal radiation therapy (brachytherapy)

Brachytherapy might be used to treat some rectal cancers, but more research is needed to understand how to best use and when to use brachytherapy.

For this treatment, a radioactive source is put inside your rectum next to or into the tumor. This allows the radiation to reach the rectum without passing through the skin and other tissues of the belly (abdomen), so it’s less likely to damage nearby tissues.

Endocavitary radiation therapy: For this treatment, a small balloon-like device is placed into the rectum to deliver high-intensity radiation for a few minutes. This is typically done in 4 treatments (or less), with about 2 weeks between each treatment. This can let some patients, particularly elderly patients, avoid major surgery and a colostomy. This type of treatment is used for some small rectal cancers or in cases where radiation was already given in the pelvic area and the rectal cancer has come back. Sometimes external-beam radiation therapy is also given.

Interstitial brachytherapy: For this treatment, a tube is placed into the rectum and right into the tumor. Small pellets of radioactive material are then put into the tube for several minutes. The radiation travels only a short distance, limiting the harmful effects on nearby healthy tissues. It’s sometimes used to treat people with rectal cancer who are not healthy enough for surgery or have cancer that has come back in the rectum. This can be done a few times a week for a couple of weeks, but it can also be just a one-time procedure.

Radioembolization

Radiation can also be given during an embolization procedure. You can find more details in Ablation and Embolization to Treat Colorectal Cancer.

Possible side effects of radiation therapy

If you’re going to get radiation therapy, it’s important to ask your doctor about the possible short- and long-term side effects so that you know what to expect. Possible side effects of radiation therapy for colon and rectal cancer can include:

• Skin irritation at the site where radiation beams were aimed, which can range from redness to blistering and peeling
• Problems with wound healing if radiation was given before surgery
• Nausea
• Rectal irritation, which can cause diarrhea, painful bowel movements, or blood in the stool
• Bowel incontinence (stool leakage)
• Bladder irritation, which can cause problems like feeling like you have to go often (called frequency), burning or pain while urinating, or blood in the urine
• Fatigue/tiredness
• Sexual problems (erection issues in men and vaginal irritation in women)
• Scarring, fibrosis (stiffening), and adhesions that cause the tissues in the treated area to stick to each other

Most side effects should get better over time after treatment ends, but some problems may not go away completely. If you notice any side effects, talk to your doctor right away so steps can be taken to reduce or relieve them.

Chemotherapy for Colorectal Cancer

When is chemotherapy used?

Chemo may be used at different times during treatment for colorectal cancer:

• Neoadjuvant chemo is given (sometimes with radiation) before surgery to try to shrink the cancer and make it easier to remove. This is often done for rectal cancer.
• Adjuvant chemo is given after surgery. The goal is to kill cancer cells that might have been left behind at surgery because they were too small to see, as well as cancer cells that might have escaped from the main colon or rectal cancer to settle in other parts of the body but are too small to see on imaging tests. This helps lower the chance that the cancer will come back.
• For advanced cancers that have spread to other organs like the liver, chemo can be used to help shrink tumors and ease problems they’re causing. While it’s not likely to cure the cancer, this often helps people feel better and live longer.

How is chemotherapy given?

You can get chemotherapy in different ways to treat colorectal cancer.

• Systemic chemotherapy: Drugs are put into your blood through a vein or you take them by mouth. The drugs enter your bloodstream and reach almost all areas of your body.
• Regional chemotherapy: Drugs are put into an artery that leads to the part of the body with the cancer. This focuses the chemo on the cancer cells in that area. It reduces side effects by limiting the amount of drug reaching the rest of your body. Hepatic artery infusion, or chemo given directly into the hepatic artery, is an example of regional chemotherapy sometimes used for cancer that has spread to the liver.

Chemo drugs for colon or rectal cancer that are given into a vein (IV), can be given either as an injection over a few minutes or as an infusion over a longer period of time. This can be done in a doctor’s office, infusion center, or in a hospital setting.

Often, a slightly larger and sturdier IV is required in the vein system to administer chemo. These are known as central venous catheters (CVCs), central venous access devices (CVADs), or central lines. They are used to put medicines, blood products, nutrients, or fluids into your blood. They can also be used to take blood for testing. There are many different kinds of CVCs. The most common types are the tunneled central lines, ports, and peripherally inserted central catheter (PICC) lines.

Chemo is given in cycles, which include a rest period to give you time to recover from the effects of the drugs. Each cycle is usually 2 or 3 weeks long. The schedule varies depending on the drugs used. For example, with some drugs, the chemo is given only on the first day of the cycle. With others, it is given for a few days in a row, or once a week. Then, at the end of the cycle, the chemo schedule repeats to start the next cycle.

Adjuvant or neoadjuvant chemo is often given for a total of 3 to 6 months, depending on the drugs used. The length of treatment for advanced colorectal cancer depends on how well it is working and what side effects you have.

Chemotherapy drugs used to treat colorectal cancer

Some drugs commonly used for colorectal cancer include:

• 5-Fluorouracil (5-FU)
• Capecitabine (Xeloda), a pill that is changed into 5-FU once it gets to the tumor
• Irinotecan (Camptosar)
• Oxaliplatin (Eloxatin)
• Trifluridine and tipiracil (Lonsurf), a combination drug in pill form

Most often, combinations of 2 or 3 of these drugs are used. Sometimes, chemo drugs are given along with a targeted therapy drug.

Possible side effects of chemo

Chemo drugs attack cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in hair follicles and in the lining of the mouth and intestines, are also dividing quickly. These cells can be affected by chemo too, which can lead to side effects.

The side effects of chemo depend on the type and dose of drugs given and how long you take them. Common side effects of chemo can include:

• Hair loss
• Mouth sores
• Loss of appetite or weight loss
• Nausea and vomiting
• Diarrhea
• Nail changes
• Skin changes

Chemo can also affect the blood-forming cells of the bone marrow, which can lead to:

• Increased chance of infections (from low white blood cell counts)
• Easy bruising or bleeding (from low blood platelet counts)
• Fatigue (from low red blood cell counts and other reasons)

Other side effects are specific to certain drugs. Ask your cancer care team about the possible side effects of the specific drugs you are getting. For example:

• Hand-foot syndrome can develop during treatment with capecitabine or 5-FU. It can start out as redness in the hands and feet, and then might progress to pain and sensitivity in the palms and soles. If it worsens, the skin may blister or peel, sometimes leading to painful sores. It’s important to tell your doctor right away about any early symptoms, such as redness or sensitivity, so that steps can be taken to keep things from getting worse.
• Neuropathy (nerve damage) is a common side effect of oxaliplatin. Symptoms include numbness, tingling, and even pain in the hands and feet. It can also cause intense sensitivity to cold in your throat, esophagus (the tube connecting the throat to the stomach), and the palms of your hands. This can cause pain when swallowing cold liquids or holding a cold glass. If you'll be getting oxaliplatin, talk with your doctor about side effects beforehand, and let them know right away if you develop numbness and tingling or other side effects.
• Allergic or sensitivity reactions can happen in some people while getting the drug oxaliplatin. Symptoms can include skin rash; chest tightness and trouble breathing; back pain; or feeling dizzy, lightheaded, or weakness. Be sure to tell your nurse right away if you notice any of these symptoms while you're getting chemo.
• Diarrhea is a common side effect with many of these chemo drugs, but can be particularly bad with irinotecan. It needs to be treated right away – at the first loose stool – to prevent severe dehydration. This often means taking a drug like loperamide (Imodium) or even being admitted to the hospital for intravenous hydration. If you're getting a chemo drug that will likely cause diarrhea, your doctor will give you instructions on what drugs to take and how often to take them to control this problem.

Most of these side effects tend to go away over time after treatment ends. Some, such as hand and foot numbness from oxaliplatin, may last for a long time. There are often ways to lessen these side effects. For example, you can be given drugs to help prevent or reduce nausea and vomiting, or you may be told to keep ice chips in your mouth while chemo is being given to lower the chances of getting mouth sores.

Be sure to discuss any questions about side effects with your cancer care team. Also report any side effects or changes you notice while getting chemo so that they can be treated right away. In some cases, the doses of the chemo drugs may need to be reduced or treatment may need to be delayed or stopped to help keep the problem from getting worse.

Targeted Therapy Drugs for Colorectal Cancer

As researchers learn more about changes in cells that cause colon or rectal cancer, they have developed new types of drugs to specifically target these changes.

When is targeted therapy used?

Targeted drugs work differently from chemotherapy (chemo) drugs. They sometimes work when chemo drugs don’t, and they often have different side effects. They can be used either along with chemo, by themselves, or in combination with another targeted therapy drug.

Like chemotherapy, these drugs enter the bloodstream and reach almost all areas of the body, which makes them useful against cancers that have spread to distant parts of the body.

Several types of targeted drugs might be used to treat colorectal cancer.

Drugs that target blood vessel formation (VEGF)

Vascular endothelial growth factor (VEGF) is a protein that helps tumors form new blood vessels (a process known as angiogenesis) to get nutrients they need to grow. Drugs that stop VEGF from working can be used to treat some colon or rectal cancers. These include:

• Bevacizumab (Avastin)
• Ramucirumab (Cyramza)
• Ziv-aflibercept (Zaltrap)
• Fruquintinib (Fruzaqla)

Most of these drugs are given as infusions into your vein (IV) every 2 or 3 weeks, in most cases along with chemotherapy. Fruquinitinib is given as a capsule and not combined with chemotherapy.  These drugs can often help people with advanced colon or rectal cancers live longer.

Possible side effects of drugs that target VEGF

Common side effects of these drugs include:

• High blood pressure
• Protein in the urine
• Bleeding (from the nose or rectum)
• Headaches
• Taste changes
• Skin changes

Rare but possibly serious side effects include blood clots, severe bleeding, holes forming in the colon (called perforations), heart problems, kidney problems, and slow wound healing. If a hole forms in the colon, it can lead to severe infection and surgery may be needed to fix it.

Another rare but serious side effect of these drugs is an allergic reaction during the infusion, which could cause problems with breathing and low blood pressure.

Drugs that target cancer cells with EGFR changes

Epidermal growth factor receptor (EGFR) is a protein that helps cancer cells grow. Drugs that target EGFR (EGFR inhibitors) can be used to treat some advanced colon or rectal cancers. These include:

• Cetuximab (Erbitux)
• Panitumumab (Vectibix)

Both of these drugs are given by IV infusion, either once a week or every other week.

These drugs typically don’t work  in colorectal cancers that have mutations (defects) in the KRAS, NRAS or BRAF gene. Doctors commonly test the tumor for these gene changes before treatment, and only use these drugs in people whose cancer cells don’t have these mutations.

One exception to this is when an EGFR inhibitor is combined with the BRAF inhibitor encorafenib (see below). The combination of these two drugs appears to help people with advanced colorectal cancer live longer.

Possible side effects of drugs that target EGFR

The most common side effects of these drugs are skin problems such as an acne-like rash on the face and chest during treatment, which can sometimes lead to infections. An antibiotic and/or steroid cream may be needed to help limit the rash and related infections. Developing this rash often means the cancer is responding to treatment. People who develop this rash often live longer, and those who develop more severe rashes also seem to respond better than those with a milder rash. Other side effects can include:

• Headache
• Tiredness
• Fever
• Diarrhea

A rare but serious side effect of these drugs is an allergic reaction during the infusion, which could cause problems with breathing and low blood pressure. You may be given medicine before treatment to help prevent this.  Other serious but rare serious side effects include eye, heart, or lung damage.

Drugs that target cells with BRAF gene changes

A small portion of colorectal cancers have changes (mutations) in the BRAF gene. Colorectal cancer cells with these changes make an abnormal BRAF protein that helps them grow. Some drugs target this abnormal BRAF protein.

If you have colorectal cancer that has spread, your cancer will likely be tested to see if the cells have a BRAF gene change known as BRAF V600E, which can cause the cell to make an abnormal BRAF protein.

Encorafenib (Braftovi) is a BRAF inhibitor – a drug that attacks the abnormal BRAF protein. When given with cetuximab or panitumumab, an EGFR inhibitor (see above), this drug can shrink or slow the growth of colorectal cancer in some people whose cancer has spread. The combination of these two drugs also appears to help people with advanced colorectal cancer live longer.

This drug is taken as capsules, once a day.

Common side effects of encorafenib, in combination with an EGFR inhibitor, can include skin thickening, diarrhea, rash, loss of appetite, abdominal pain, joint pain, fatigue, and nausea.

Some people treated with a BRAF inhibitor might develop new squamous cell skin cancers. These cancers can often be treated by removing them. Still, your doctor will want to check your skin regularly during treatment and for several months afterward. You should also let your doctor know right away if you notice any new growths or abnormal areas on your skin.

Drugs that target cells with HER2 changes

In a small percentage of people with colorectal cancer, the cancer cells have too much of a growth-promoting protein called HER2 on their surface. Cancers with increased levels of HER2 are called HER2-positive. Drugs that target the HER2 protein can often be helpful in treating these cancers.

Drugs of this type that might be used to treat HER2-positive colorectal cancer include:

• Trastuzumab (Herceptin, other names)
• Pertuzumab (Perjeta)
• Tucatinib (Tukysa)
• Lapatinib (Tykerb)
• Fam-trastuzumab deruxtecan (Enhertu, T-DXd)

For advanced, HER2-positive colorectal cancer that has already been treated with chemotherapy, the most common targeted drug regimens include trastuzumab plus either tucatinib, lapatinib, or pertuzumab. Patients who are considered to be treated with this regimen must also not have mutations in the RAS and BRAF genes.

Among these drugs, only tucatinib is FDA approved specifically to treat colorectal cancer at this time, but the others are present in treatment guidelines. Still, it’s important to check with your insurance provider before getting these drugs to make sure they are covered.

The side effects of HER2-targeted drugs tend to be mild overall, but some can be serious, and different drugs can have different possible side effects. Discuss what you can expect with your doctor.

Some of these drugs can cause heart damage during or after treatment, which might lead to congestive heart failure. Because of this, your doctor will likely check your heart function (with an echocardiogram or a MUGA scan) before treatment, and regularly while you are getting any of these drugs. Let your doctor know if you develop symptoms, such as shortness of breath, a fast heartbeat, leg swelling, and severe fatigue.

Some of these drugs can cause severe diarrhea, so it’s very important to let your health care team know about any changes in bowel habits as soon as they happen.

Lapatinib and tucatinib can also cause hand-foot syndrome, in which the hands and feet become sore and red, and may blister and peel.

Lapatinib and tucatinib can cause liver problems. Your doctor will do blood tests to check your liver function during treatment. Let your health care team know right away if you have possible signs or symptoms of liver problems, such as itchy skin, yellowing of the skin or the white parts of your eyes, dark urine, or pain in the right upper belly area.

Fam-trastuzumab deruxtecan can cause serious lung disease in some people, which might even be life threatening. It’s very important to let your doctor know right away if you’re having symptoms such as coughing, wheezing, trouble breathing, or fever.

Drugs that target cells with NTRK gene changes

A very small number of colorectal cancers have changes in one of the NTRK genes. This causes them to make abnormal TRK proteins, which can lead to abnormal cell growth and cancer.

Larotrectinib (Vitrakvi) and entrectinib (Rozlytrek) are drugs that target the TRK proteins. These drugs can be used to treat advanced cancers with NTRK gene changes that are still growing despite other treatments.

These drugs are taken as pills or an oral solution, once or twice daily.

Common side effects of these drugs can include dizziness, fatigue, nausea, vomiting, constipation, weight gain, and diarrhea.

Less common but serious side effects can include abnormal liver tests, increased risk for fractures, heart problems, vision changes, and confusion.

Drugs that target cells with RET gene changes

A very small number of colorectal cancers have changes in one of the RET genes. This causes them to make abnormal RET proteins, which can lead to abnormal cell growth and cancer.

Selpercatinib (Retevmo) is a drug that targets the RET protein. These drugs can be used to treat advanced cancers with RET gene changes that are still growing despite other treatments.

This drug is taken as a capsule twice daily.

This drug is approved to treat other types of cancer, but doctors can prescribe it off-label for colorectal cancer. Still, it’s important to check with your insurance provider before getting these drugs to make sure they are covered.

Common side effects of these drugs can include decrease in white blood cell count and calcium, changes in liver function tests, high blood pressure, fatigue, changes in kidney function, and increased cholesterol.

Less common but serious side effects can include abnormal heart function (QT interval prolongation), bleed, allergic reaction, and inability to heal from a wound.

Drugs that target cells with KRAS gene changes

A very small number of colorectal cancers have the KRAS G12C gene mutation. This causes them to make abnormal KRAS proteins, which can lead to continued cell growth and cancer.

Adagrasib (Krazati) and Sotorasib (Lumakras) are drugs that target the KRAS proteins. Adagrasib can be given with cetuximab (EGFR inhibitor) to treat advanced cancers with KRAS gene changes that are still growing despite other treatments. Sotorasib is not approved specifically to treat colorectal cancer at this time. It is approved to treat other types of cancer, but doctors can prescribe them off-label for colorectal cancer. Still, it’s important to check with your insurance provider before getting these drugs to make sure they are covered.

These drugs are taken as tablets, once or twice daily.

Common side effects of these drugs can include nausea, vomiting, diarrhea, muscle and joint pain, fatigue, decreased appetite, and changes in liver and kidney function.

Less common but serious side effects can include effects to the heart (QTc interval prolongation), liver, and lungs (interstitial lung disease).

Other targeted therapy drugs

Regorafenib (Stivarga) is a type of targeted therapy known as a multikinase inhibitor. Kinases are proteins on or near the surface of a cell that carry important signals to the cell’s control center. Regorafenib blocks several kinase proteins that either help tumor cells grow or help form new blood vessels to feed the tumor. Blocking these proteins can help stop the growth of cancer cells.

This drug can be used to treat advanced colorectal cancer, typically when other drugs are no longer helpful. It’s taken as a pill.

Common side effects include fatigue, rash, hand-foot syndrome (redness and irritation of the hands and feet), diarrhea, high blood pressure, weight loss, and abdominal pain.

Less common but more serious side effects can include confusion, severe bleeding, or perforations (holes) in the stomach or intestines.

Immunotherapy for Colorectal Cancer

Immunotherapy is the use of medicines to help a person’s own immune system better recognize and destroy cancer cells.

Immune checkpoint inhibitors

For people with either early- or advanced-stage colorectal cancer, immunotherapy is now a cornerstone of treatment if the tumor has findings of dMMR (deficient mismatch repair) or MSI-H (microsatellite instability-high).

An important part of the immune system is its ability to keep itself from attacking the body’s normal cells. To do this, it uses “checkpoints” – proteins on immune cells that need to be turned on (or off) to start an immune response. Colorectal cancer cells sometimes use these checkpoints to avoid being attacked by the immune system. Drugs that target these checkpoints help to restore the immune response against colorectal cancer cells.

Drugs called checkpoint inhibitors can be used for people whose colorectal cancer cells have tested positive for specific gene changes, specifically a high level of microsatellite instability (MSI-H), or changes in one of the mismatch repair (MMR) genes. These drugs might be given to people before surgery for early-stage colon cancer, or to treat people whose cancer can’t be removed with surgery, has come back (recurred) after treatment, or has spread to other parts of the body (metastasized).

PD-1 inhibitors

Pembrolizumab (Keytruda), nivolumab (Opdivo), and Dostarlimb (Jemperli) are drugs that target PD-1, a protein on immune system cells called T cells that normally help keep these cells from attacking other cells in the body. By blocking PD-1, these drugs boost the immune response against colorectal cancer cells. They are only given if the tumor has had findings of dMMR or MSI-H.

Pembrolizumab can be given alone. It is given as an intravenous (IV) infusion every 3 or 6 weeks.

Nivolumab can be given alone or with ipilimumab (see below). It is typically given by itself as an IV infusion every 2 or 4 weeks. If it is used along with ipilimumab, then it is typically given every 3 weeks.

Dostarlimab can be given alone. It is given as an intravenous (IV) infusion every 3 weeks for 4 treatments, and then given at a higher dose every 6 weeks. This drug is not approved specifically to treat colorectal cancer at this time. It is approved to treat other types of cancer, but doctors can prescribe it off-label for colorectal cancer. Still, it’s important to check with your insurance provider before getting this drug to make sure it is covered.

CTLA-4 inhibitor

Ipilimumab (Yervoy) is another drug that boosts the immune response, but it has a different target. It blocks CTLA-4, another protein on T cells that normally helps keep them in check.

This drug can be used along with nivolumab (Opdivo) to treat colorectal cancer, but it’s not used alone. It is given as an intravenous (IV) infusion, usually once every 3 weeks for 4 treatments.

Possible side effects of immunotherapy

Side effects of these drugs include fatigue, cough, nausea, diarrhea, skin rash, loss of appetite, constipation, joint pain, and itching.

Other, more serious side effects occur less often.

Infusion reactions: Some people might have an infusion reaction while getting these drugs. This is like an allergic reaction, and can include fever, chills, flushing of the face, rash, itchy skin, feeling dizzy, wheezing, and trouble breathing. It’s important to tell your doctor right away if you have any of these symptoms while getting these drugs.

Autoimmune reactions: These drugs work by basically removing one of the safeguards on the body’s immune system. Sometimes the immune system starts attacking other parts of the body, which can cause serious or even life-threatening problems in the lungs, intestines, liver, hormone-making glands, nerves, skin, kidney, or other organs.

It’s very important to report any new side effects during or after treatment with any of these drugs to your health care team promptly. If serious side effects do occur, you may need to stop treatment and take high doses of corticosteroids to suppress your immune system.

Treatment of Colon Cancer, by Stage

Treatment for colon cancer is based largely on the stage (extent) of the cancer, but other factors can also be important.

People with colon cancers that have not spread to distant sites usually have surgery as the main or first treatment. Chemotherapy may also be used after surgery (called adjuvant treatment). Most adjuvant treatment is given for about 3 to 6 months.

Treating stage 0 colon cancer

Since stage 0 colon cancers have not grown beyond the inner lining of the colon, surgery to take out the cancer is often the only treatment needed. In most cases, this can be done by removing the polyp or taking out the area with cancer through a colonoscope (local excision). Removing part of the colon (partial colectomy) may be needed if a cancer is too big to be removed by local excision.

Treating stage I colon cancer

Stage I colon cancers have grown deeper into the layers of the colon wall, but they have not spread outside the colon wall itself or into the nearby lymph nodes.

Stage I includes cancers that were part of a polyp. If the polyp is removed completely during colonoscopy, with no cancer cells at the edges (margins) of the removed piece, no other treatment may be needed.

If the cancer in the polyp is high grade, or there are cancer cells at the edges of the polyp, more surgery might be recommended. You might also be advised to have more surgery if the polyp couldn’t be removed completely or if it had to be removed in many pieces, making it hard to see if cancer cells were at the edges.

For cancers not in a polyp, partial colectomy ─ surgery to remove the section of colon that has cancer and nearby lymph nodes ─ is the standard treatment. You typically won’t need any more treatment.

Treating stage II colon cancer

Stage II colon cancers have grown through the wall of the colon (called the muscularis propria), and may have even invaded into nearby tissue, but they have not spread to the lymph nodes.

Surgery to remove the section of the colon containing the cancer (partial colectomy) along with nearby lymph nodes may be the only treatment needed.

In certain cases, neoadjuvant therapy (therapy before surgery) may be recommended for stage II colon cancer, especially if the tumor has invaded or is attached to neighboring organs (T4b). This is generally considered for locally advanced colon cancer that is not initially operable. Decisions about what type of neoadjuvant therapy to give in these cases depends on whether the tumor has dMMR or MSI-H. If the tumor is dMMR or MSI-H, neoadjuvant immunotherapy (either PD-1 inhibitor alone or combination PD-1 and CTLA-4 inhibitor) is generally recommended. The type and duration of this therapy can vary as this approach remains very new. If the tumor is not dMMR or MSI-H, neoadjuvant chemotherapy is generally recommended.

If you did not receive neoadjuvant chemotherapy, after you recover from the colon surgery for treatment of Stage II cancer and if the tumor is found to not have dMMR or MSI-H, your doctor may recommend adjuvant chemo if your cancer has a higher risk of coming back (recurring) because of certain factors, such as:

• The cancer looks very abnormal (is high grade) when viewed closely in the lab.
• The cancer has grown through the colon wall (T4).
• The cancer has grown into nearby blood or lymph vessels.
• The surgeon did not remove at least 12 lymph nodes.
• Cancer was found in or near the margin (edge) of the removed tissue, meaning that some cancer may have been left behind.
• The cancer blocked (obstructed) the colon.
• The cancer caused a perforation (hole) in the wall of the colon.

If adjuvant chemo is given for high-risk stage II colon cancers, doctors generally recommend 5-FU or capecitabine. At times, oxaliplatin may also be offered. Each patient case is different and requires discussion about the risks and benefits of adjuvant chemo, as well as which type of chemo. Not all doctors agree on when chemo should be used for stage II colon cancers. It’s important for you to discuss the risks and benefits of chemo with your doctor, including how much it might reduce your risk of recurrence and what the likely side effects will be.

Treating stage III colon cancer

Stage III colon cancers have spread to nearby lymph nodes, but they have not yet spread to other parts of the body.

Surgery to remove the section of the colon with the cancer (partial colectomy), along with nearby lymph nodes, followed by adjuvant chemo is the standard treatment for this stage.

For chemo, either the FOLFOX (5-FU, leucovorin, and oxaliplatin) or CapeOx (capecitabine and oxaliplatin) regimens are used most often, but some patients may get 5-FU with leucovorin or capecitabine alone based on their age and health needs. In the past, most patients were recommended to received 6 months of adjuvant chemo for treatment of stage III colon cancer. Recent research has shown that 3 months of adjuvant chemo for some stage III colon cancers may be just as effective and is acceptable.

For some advanced colon cancers that cannot be removed completely by surgery (either tumor has invaded through the colon wall or presence of large bulky lymph nodes), neoadjuvant chemotherapy or neoadjuvant immunotherapy might be recommended to shrink the cancer so it can be removed later with surgery. Neoadjuvant chemotherapy is usually recommended if the tumor is pMMR or MSS. Neoadjuvant immunotherapy is usually recommended if the tumor is dMMR or MSI-H.

For some advanced cancers that have been removed by surgery but were found to be attached to a nearby organ or have positive margins (some of the cancer may have been left behind), adjuvant radiation therapy might be recommended. Radiation therapy and/or chemo may also be options for people who aren’t healthy enough for surgery or for when complete resection is not possible due to tumor location.

Treating stage IV colon cancer

Stage IV colon cancers have spread from the colon to distant organs and tissues. Colon cancer most often spreads to the liver, but it can also spread to other places like the lungs, brain, peritoneum (the lining of the abdominal cavity), or to distant lymph nodes.

In most cases, surgery is unlikely to cure these cancers. But if there are only a few small areas of cancer spread (metastases) in the liver or lungs and they can be removed along with the colon cancer, surgery may help you live longer. This would mean having surgery to remove the section of the colon containing the cancer along with nearby lymph nodes, plus surgery to remove the areas of cancer spread. In some cases, if the liver metastasis is not able to be surgically removed, ablation or embolization may be an option.

Chemo may begiven before and/or after surgery. If the metastases cannot be removed because they’re too big or there are too many of them, chemo may be given before surgery (neoadjuvant chemo). Then, if the tumors shrink, surgery may be tried to remove them. Chemo might be given again after surgery.

If the cancer has spread too much to try to cure it with surgery, chemo is the main treatment. Surgery might still be needed if the cancer is blocking the colon or is likely to do so. Sometimes, such surgery can be avoided by putting a stent (a hollow metal tube) into the colon during a colonoscopy to keep it open. Otherwise, operations such as a colectomy or a diverting colostomy (cutting the colon above the level of the cancer and attaching the end to an opening in the skin on the belly to allow waste out) may be used.

If you have stage IV cancer and your doctor recommends surgery, it’s very important to understand the goal of the surgery ─ whether it’s to try to cure the cancer or to prevent or relieve symptoms of the cancer.

Most people with stage IV cancer will get chemo and/or targeted therapies to control the cancer. Some of the most commonly used regimens include:

• FOLFOX: leucovorin, 5-FU, and oxaliplatin
• FOLFIRI: leucovorin, 5-FU, and irinotecan
• CAPEOX: capecitabine and oxaliplatin
• FOLFOXIRI: leucovorin, 5-FU, oxaliplatin, and irinotecan
• One of the above chemo combinations, plus either a drug that targets VEGF(bevacizumab, ziv-aflibercept or ramucirumab), or a drug that targets EGFR (cetuximab or panitumumab)
• 5-FU and leucovorin, with or without a targeted drug
• Capecitabine, with or without a targeted drug
• Irinotecan, with or without a targeted drug
• Cetuximab or Panitumumab
• Regorafenib, Trifluridine and tipiracil (Lonsurf), alone or in combination with Bevacizumab

The choice of regimens depends on several factors, including any previous treatments you’ve had and your overall health. If one of these regimens is no longer working, another may be tried.

For people whose cancer cells have changes in certain genes or proteins, targeted therapy drugs might be an option.

For people whose cancers cells have high levels of microsatellite instability (MSI) or changes in one of the MMR genes, an immunotherapy drug, such as pembrolizumab, nivolumab or Dostarlimab, may be an option.

For advanced cancers, radiation therapy can also be used to help prevent or relieve symptoms in the colon from the cancer such as pain. It might also be used to treat areas of spread such as in the lungs or bone. It may shrink tumors for a time, but it’s not likely to cure the cancer. If your doctor recommends radiation therapy, it’s important that you understand the goal of treatment.

Treating right-sided versus left-sided colon cancer

In recent years, research has shown that the genetic mutations found in colon cancer can be different depending on whether it started on the right or left side of the colon. These differences can affect how the cancer responds to certain treatments as well as a person’s prognosis (how well they do after treatment).

Right-sided colon cancer

The right-side of the colon includes the cecum, ascending colon, and about 2/3 of the transverse colon. Cancers that start on the right side of the colon are:

• Less common than left-sided colon cancer
• More likely to occur in older age
• More likely linked to a hereditary cancer syndrome
• More likely to be dMMR or MSI-H
• More likely to have a BRAF or KRAS mutation

These cancers tend to have a poorer prognosis if the cancer has advanced or spread outside the colon, compared to advanced cancers that started on the left. They are also unlikely to respond to anti-EGFR therapy, even if the tumor tests negative for RAS and BRAF mutations. Right-sided colon cancer may be more responsive to immunotherapy, compared to left-sided colon cancers.

Left-sided colon cancer

The left-side of the colon includes the rest of the colon, which includes the remaining 1/3 of the transverse colon, the descending colon, and the sigmoid colon. Cancers that start on the left side of the colon are:

• More common than right-sided colon cancer
• More likely to occur in younger age
• More likely to be diagnosed at an earlier stage due to symptoms
• More likely to have a HER2 mutation

These cancers tend to have a better prognosis if the cancer has advanced or spread outside the colon, compared to advanced cancers that started on the right. They are also more responsive to anti-EGFR therapy, if tests are negative for RAS and BRAF mutations. Left-sided colon cancers may be more responsive to chemotherapy, compared to right-sided colon cancers.

Treating recurrent colon cancer

Recurrent cancer means that the cancer has come back after treatment. The recurrence may be local (near the area of the initial tumor), or it may be in distant organs.

Local recurrence

If the cancer comes back locally, surgery (often followed by chemo) can sometimes help you live longer and may even cure you. If the cancer can’t be removed surgically, chemo might be tried first. If it shrinks the tumor enough, surgery might be an option. This might be followed by more chemo.

Distant recurrence

If the cancer comes back in a distant site, it’s most likely to appear in the liver first. Surgery might be an option for some people. If not, chemo may be tried to shrink the tumor(s), which may then be followed by surgery to remove them. Ablation or embolization techniques might also be an option to treat some liver tumors.

If the cancer has spread too much to be treated with surgery, chemotherapy ,targeted therapies, and/or immunotherapy may be used. Possible treatment schedules are the same as for stage IV disease.

Your options depend on which, if any, drugs you had before the cancer came back and how long ago you got them, as well as your overall health. You may still need surgery at some point to relieve or prevent blockage of the colon or other local problems. Radiation therapy may be an option to relieve symptoms as well.

Recurrent cancers can often be hard to treat, so you might also want to ask your doctor if clinical trials of newer treatments are available.

For more on recurrence, see Understanding Recurrence.

Living as a Colorectal Cancer Survivor

For many people with colorectal cancer, treatment can remove or destroy the cancer. The end of treatment can be both stressful and exciting. You may be relieved to finish treatment but find it hard not to worry about cancer coming back. This is very common if you’ve had cancer.

For other people, colorectal cancer may never go away completely. Some people may get regular treatment with chemotherapy, radiation therapy, or other treatments to try to control the cancer for as long as possible. Learning to live with cancer that does not go away can be difficult and very stressful.

Ask your doctor for a survivorship care plan

Talk with your doctor about developing a survivorship care plan for you. This plan might include:

• A suggested schedule for follow-up exams and tests
• A list of possible late or long-term side effects from your treatment, including what to watch for and when you should contact your doctor
• A schedule for other tests you might need in the future, such as early detection (screening) tests for other types of cancer
• Suggestions for things you can do that might improve your health, including possible ways to lower your chances of the cancer coming back, such as diet and physical activity changes
• Reminders to keep your appointments with your primary care provider (PCP), who will monitor your general health care, including your cancer screening tests

Follow-up care after colorectal cancer

If you have completed treatment, you will likely have follow-up visits with your doctor for many years. It’s very important to go to all of your follow-up appointments. During these visits, your doctors will ask if you are having any problems and may do exams and lab tests or imaging tests to look for signs of cancer returning, a new cancer, or treatment side effects.

To some extent, the frequency of follow-up visits and tests will depend on the stage of your cancer and the chance of it coming back.

Almost any cancer treatment can have side effects. Some might last for a few days or weeks, but others may last months or years. Some side effects might not even show up until months after you have finished treatment. Your doctor visits are a good time to ask questions and talk about any changes or problems you notice or concerns you have.

Doctor visits and tests

If there are no signs of cancer remaining, many doctors will recommend you have a physical exam and some of the tests listed below every 3 to 6 months for the first couple of years after treatment, then every 6 months or so for the next few years. People who were treated for early-stage cancers may do this less often.

Colonoscopy

In most cases, your doctor will recommend you have a colonoscopy about a year after surgery. If the results are normal, most people won’t need another one for 3 years. If the results of that exam are normal, then future exams often can be about every 5 years. If the colonoscopy shows abnormal areas or polyps, the test may be needed more often.

Proctoscopy

If you had rectal cancer that was removed with a transanal excision (the surgery was done through your anus), your doctor will likely recommend you have a proctoscopy every 3 to 6 months for the first couple of years after treatment, then every 6 months or so for the next few years. This allows the doctor to get a close look at the area where the tumor was to see if the cancer might be coming back.

Imaging tests

Whether or not your doctor recommends imaging tests will depend on the stage of your cancer and other factors. CT scans may be done regularly, such as once every 6 months to a year, for those at higher risk of recurrence, especially in the first few years after treatment. People who had tumors in the liver or lungs removed might be scanned every 3 to 6 months for the first few years.

Blood tests for tumor markers

Carcinoembryonic antigen (CEA) is a tumor marker that can be found in the blood of some people with colorectal cancer. Doctors check levels of this marker with a blood test before treatment begins.

If it’s high at first and then goes down to normal after surgery, it can be checked again when you come in for follow-up (typically every 3 to 6 months for the first couple of years after treatment, then every 6 months or so for the next few years). If the CEA level goes up again, it might be a sign that the cancer has come back, and colonoscopy or imaging tests might be done to try to  further investigate.

If tumor marker levels weren’t elevated when the cancer was first found, they aren’t likely to be helpful as a sign of the cancer coming back.

Keeping health insurance and copies of your medical records

Even after treatment, it’s very important to keep health insurance. Tests and doctor visits cost a lot, and even though no one wants to think of their cancer coming back, this could happen.

At some point after your cancer treatment, you might find yourself seeing a new doctor who doesn’t know about your medical history. It’s important to keep copies of your medical records to give your new doctor the details of your diagnosis and treatment.

Managing long-term side effects

Most side effects go away after treatment ends, but some may continue and need special care to manage. For example, if you have a colostomy or ileostomy, you may worry about doing everyday activities. Whether your ostomy is temporary or permanent, a health care professional trained to help people with colostomies and ileostomies (called an enterostomal therapist) can teach you how to care for it. Learn more about managing and caring for an ostomy in Colostomy Guide and Ileostomy Guide.

Some people with colon or rectal cancer may have long-lasting trouble with chronic diarrhea, going to the bathroom frequently, or not being able to hold their stool. Some may also have problems with numbness or tingling in their fingers and toes (peripheral neuropathy) from chemo they received.

Can I lower my risk of colorectal cancer progressing or coming back?

If you have (or have had) colorectal cancer, you probably want to know if there are things you can do (aside from your treatment) that can help lower your risk of the cancer growing or coming back, such as getting or staying active, eating a certain type of diet, or taking nutritional supplements. Fortunately, research has shown there are some things you can do that might be helpful.

Getting to and staying at a healthy weight

Being overweight or obese (very overweight) is known to increase the risk of getting colorectal cancer. However, it’s not clear if having extra body weight raises the risk of colorectal cancer coming back or of dying from colorectal cancer. It’s also not clear if losing weight during or after treatment can actually lower the risk of colorectal cancer recurrence.

Of course, getting to a healthy weight can have many other health benefits. But if you’re thinking about losing weight, it’s important to discuss this with your doctor, especially if you’re still getting treatment or have just finished it.

Being active

A good deal of research suggests that people who get regular physical activity after treatment have a lower risk of colorectal cancer recurrence and a lower risk of dying from colorectal cancer. Physical activity has also been linked to improvements in quality of life, physical functioning, and fewer fatigue symptoms. It’s not clear exactly how much activity might be needed, but more seems to be better.

Some studies have also found that spending less time sitting or lying down is linked to a lower risk of dying from colorectal cancer.

It’s important to talk with your cancer care team before starting a new physical activity program. This might include meeting with a physical therapist, too. Your team can help you plan a program that can be both safe and effective for you.

Eating healthy

In general, it’s not clear that eating any specific type of diet can help lower your risk of colorectal cancer coming back. Some studies suggest that colorectal cancer survivors who eat diets high in vegetables, fruits, whole grains, chicken, and fish might live longer than those who eat diets with more refined sugars, fats, and red or processed meats. But it’s not clear if this is due to effects on colorectal cancer or possibly to other health benefits of eating a healthy diet.

Still, there are clearly health benefits to eating well. For example, diets that are rich in plant sources are often an important part of getting to and staying at a healthy weight. Eating a healthy diet can also help lower your risk for some other health problems, such as heart disease and diabetes.

Dietary supplements

So far, no dietary supplements have been shown to clearly help lower the risk of colorectal cancer progressing or coming back. This doesn’t mean that none will help, but it’s important to know that none have been proven to do so.

Vitamin D: Some research has suggested that colorectal cancer survivors with higher levels of vitamin D in their blood might have better outcomes than those with lower levels. Other research has suggested that people with colorectal cancer who have low vitamin D levels may have a worse survival than those with normal levels, but more studies are needed. But it’s not yet clear if taking vitamin D supplements can affect outcomes.

Calcium: Some research has suggested that increasing calcium intake may lower the risk for recurrence of colon adenomas. Other research has suggested that people with early-stage colorectal cancer who take in a higher level of milk and calcium may have a lower the risk of dying. But it’s not clear if calcium supplements can lower the risk of colorectal cancer coming back.

Dietary supplements are not regulated like medicines in the United States – they do not have to be proven to work (or even be safe) before being sold, although there are limits on what they’re allowed to claim they can do. If you're thinking about taking any type of nutritional supplement, talk to your cancer care team first. They can help you decide which ones you can use safely while avoiding those that could be harmful.

Aspirin

Many studies have found that people who regularly take aspirin have a lower risk of colorectal cancer and polyps. Some evidence suggests that starting aspirin after someone is diagnosed with colorectal cancer might lower the risk of the cancer coming back and the risk of dying from it. It is not clear, though, if this benefit is seen in all people with colorectal cancer.

Because aspirin can have serious or even life-threatening side effects, such as bleeding from stomach irritation or stomach ulcers, most experts recommend checking with your doctor before starting aspirin on a regular basis as a way to lower your risk of recurrence.

Alcohol

Drinking alcohol has been linked with an increased risk of getting colorectal cancer, especially in men. But whether alcohol affects the risk of colorectal cancer recurrence is not as clear.

It is best not to drink alcohol. For people who do drink alcohol, they should have no more than 1 drink a day for women and no more than 2 drinks a day for men. This can help lower their risk of getting certain types of cancer (including colorectal cancer). But for people who have finished cancer treatment, the effects of alcohol on recurrence risk are largely unknown.

Because this issue is complex, it’s important to discuss it with your health care team, taking into account your risk of colorectal cancer recurrence (or getting a new colorectal cancer) and your risk of other health issues linked to alcohol use.

Quitting smoking

Research has shown that colorectal cancer survivors who smoke are more likely to die from their cancer (as well as from other causes). Aside from any effects on colorectal cancer risk, quitting smoking can clearly have many other health benefits.

If you're thinking about quitting smoking and need help, talk to your doctor, or call the American Cancer Society at 1-800-227-2345 for information and support.

If the cancer comes back

If the cancer does return at some point, your treatment options will depend on where the cancer is, what treatments you’ve had before, and your overall health. For more information on how recurrent cancer is treated, see Treatment of Colon Cancer, by Stage or Treatment of Rectal Cancer, by Stage.

For more general information on recurrence, see Understanding Recurrence.

Could I get a second cancer after colorectal cancer treatment?

People who’ve had colorectal cancer can still get other cancers. In fact, colorectal cancer survivors are at higher risk for getting another colorectal cancer, as well as some other types of cancer. Learn more in Second Cancers After Colorectal Cancer.

Emotional support

It is normal to feel depressed, anxious, or worried when colorectal cancer is a part of your life. Some people are affected more than others. But everyone can benefit from help and support from other people, whether friends and family, religious groups, support groups, professional counselors, or others.

Sexuality and feeling good about your body

Learning to be comfortable with your body during and after colorectal cancer treatment is a personal journey, one that is different for everyone. Some people may feel self-conscious if they have a colostomy or ileostomy as a result of treatment. Some people may have sexual problems as a result of the type of surgery they had for their cancer. Information and support can help you cope with these changes over time. Learn more in Sexuality for the Adult Male With Cancer or Sexuality for the Adult Female With Cancer.

Sources:

https://www.cancer.org/cancer/types/colon-rectal-cancer.html

https://www.businessinsider.com/what-to-know-about-colon-cancer-symptoms-diagnosis-chadwick-boseman

Read More: This article is part of the Winning the War on Cancer series.

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