Ulcerative Colitis and Colon Cancer: What Is Your Risk?

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Ulcerative colitis (UC) is an inflammatory bowel disease that affects the large intestine, also known as the colon. Symptoms of UC can include bloody stools, pain, and persistent diarrhea.

Research suggests that those with UC are at an increased risk of colorectal cancer (cancer that starts in the colon or rectum). The degree of risk may vary based on how long a person has had UC, how severe inflammation related to the condition is, and how much of the large intestine is affected by the disease.

Reducing the Risk of Colorectal Cancer - Illustration by Jessica Olah

Verywell / Jessica Olah

Because of this risk, it's important for those living with ulcerative colitis to be regularly screened for bowel cancer. The number of UC patients diagnosed with bowel cancer has dropped in recent years, and it is believed that more proactive screening has played a role in this decline.

This article will explain more about the link between ulcerative colitis and cancer, the importance of screening, and preventive measures to reduce your risk of cancer.

Ulcerative Colitis and Cancer: What Is the Connection?

People living with ulcerative colitis (UC) are 4 to 10 times more likely to be diagnosed with colorectal cancer compared with the general population.

This is because UC patients have higher levels of inflammation in the colon and an increased risk of developing inflammatory polyps (abnormal growths) in the lining of the colon or rectum. The majority of polyps are benign (noncancerous), but over time, some polyps can become cancerous.

The exact risk of colorectal cancer for people with UC varies depending on these three factors:

  • Duration of the disease: It is believed that the risk of developing colorectal cancer starts to increase eight to 10 years following the onset of UC symptoms. One meta-analysis (statistical analysis of primary studies' data) of 116 studies found that 10 years after onset, the risk is 1.6%; at 20 years, it increases to 8.3%; and 30 years after onset, it increases to 18.4%.
  • Severity of inflammation: The more inflammation that is in your colon or rectum, the more damage there is to cells in the colon lining. This causes more cell turnover, which allows more opportunity for mutations (changes) in the DNA of these cells that can lead to cancer.
  • How much of the colon is affected: Those with UC of the entire colon are at the highest risk. If UC only affects the left side of the colon, the risk of developing cancer is lower. And those with UC only in the rectum (proctitis) don't have a heightened risk of colorectal cancer.

Other Risk Factors

In addition to UC, there are a number of risk factors that may contribute to the development of colorectal cancer. Other possible risk factors are:

  • Having a family history of bowel cancer, even if the family member with cancer didn't also have UC
  • Being over 50 years old
  • Having primary sclerosing cholangitis (PSC), a rare liver disease that develops in around 1 in 25 UC patients
  • Being male

Survival Rates

People with UC who do develop colorectal cancer have a slightly worse prognosis than those who don't have UC. But if the cancer is diagnosed early, it can be treated effectively.

If cancer is localized to the colon or rectum, the five-year survival rate is 91%. If cancer is found when it has spread to nearby structures in the body or to nearby lymph nodes, the five-year survival rate is 72%. If the cancer has spread to distant organs like the lungs or liver, the five-year survival rate is 14%.

The Importance of Colorectal Cancer Screening

Regular screening for colorectal cancer is important for people living with ulcerative colitis (UC) because it increases the likelihood of catching cancer in its earliest, most treatable stages.

Screening is done via a colonoscopy, a procedure in which a long, flexible tube with a camera (a colonoscope) is inserted into the rectum and used to look at the inside of the colon. This allows your doctor to identify and remove any polyps or other tissue that may be precancerous.

Recent technological advances have improved methods for identifying cancer or precancer in the large intestine during a colonoscopy. For instance, a chromoendoscopy may be used to identify polyps and precancerous changes in the large intestine. This involves using a blue contrast dye to highlight any changes to the lining of the intestine.

According to the Crohn's and Colitis Foundation, those who have had UC symptoms for a period of eight or more years should have a colonoscopy every one to two years. The exception to this is those who have both UC and the liver disease PSC. In this case, surveillance through colonoscopy should begin as soon as a UC diagnosis has been given.

What to Expect During a Colonoscopy

About 24 hours before a colonoscopy, you will be asked to clear your bowels with laxatives, enemas, or an all-liquid diet. Be sure to follow the fasting instructions given to you by your healthcare provider.

On the day of the procedure, you will be asked to change into a hospital gown and given a sedative and pain medication, either orally by pill or intravenously (IV, within a vein). In most cases, you will be awake (but kept very relaxed with medication) during the procedure.

Once sedated, your doctor will ask you to lie on your left side, insert the colonoscope through the rectum and use the tool to take pictures. They will also remove any polyps and tissue samples.

The procedure usually takes about 30 minutes, and then you will moved to a recovery room to allow the sedative to wear off. Typically, you will be able to go home the same day.

Strategies to Reduce Your Risk of Colorectal Cancer

Having regular colonoscopies is one of the most important preventive measures people with ulcerative colitis (UC) can take to reduce the risk of colorectal cancer.

There are also other steps people with UC can take to minimize risk, including avoiding smoking, limiting alcohol intake, maintaining a healthy weight, and exercising regularly.

Other tactics that have been shown to reduce the risk of colorectal cancer include the following:

Keep Up With Regular Physicals

Getting an annual physical is always smart, but it's especially important if you have UC.

During the checkup, your healthcare provider will ask whether your treatments are going well and ensure that screening is performed at the appropriate intervals to catch any cancer in the early stages. Even if your UC symptoms are in remission (period of reduced symptoms), seeing a healthcare provider regularly can help ensure that you stay on the healthy track.

Take Prescribed Medications

Inflammation is the biggest factor associated with an increased risk of colorectal cancer, so any medications that have been prescribed to manage inflammation from your UC may play an important role in reducing your cancer risk.

Some limited research has shown a decreased risk of colorectal cancer in UC patients treated with certain anti-inflammatory medications.

Eat a Healthy Diet

Most experts recommend sticking to a low-fat, high-fiber diet, and consuming plenty of antioxidant fruits and vegetables to reduce your overall risk of cancer.

Research has found a convincing link between increased consumption of processed or red meat and higher rates of colorectal cancer. Reducing or limiting your intake of meat, including steak, bacon, sausage, hot dogs, and deli meats like ham and salami, is one way to directly lower your risk of colorectal cancer.

In addition to reducing meat, increasing your intake of fiber, cruciferous vegetables (such as broccoli, Brussels sprouts, kale, and cauliflower), and foods rich in calcium (like milk, cheese, and leafy greens) may also help to lower your colorectal cancer risk.


Having ulcerative colitis may increase your risk of developing colorectal cancer. The risk varies depending on how long you have had UC symptoms, how severe the inflammation from UC is, and how much of the colon is affected.

Getting colonoscopies every one to two years, starting eight to 10 years after your initial UC diagnosis, is critical to catching cancer at its earliest and most treatable stage. If you have UC, adopting a health-promoting lifestyle that includes a low-fat diet, regular exercise, and keeping up with your medication can help reduce your risk.

A Word From Verywell

If you or a loved one is struggling with ulcerative colitis, it's natural to be alarmed and frustrated to have to worry about yet another complication of your condition. But remember that while colonoscopies are never pleasant, regular screenings put control back in your hands and let you stay on top of your health.

Having awareness of your increased colorectal cancer risk also empowers you to consult your healthcare provider if you develop any worrisome symptoms, such as blood in the stool or abdominal cramps, or if you have any other concerns about your condition.

Most people with UC will never develop cancer. Taking measures to both manage your UC symptoms and reduce your risk of colorectal cancer, such as eating a healthy diet, exercising, reducing red and processed meat intake, and quitting smoking, are all great steps to cultivating great peace of mind and forging ahead in good health.

Frequently Asked Questions

  • What is a colonoscopy and how does it work?

    A colonoscopy is a medical procedure used to look for changes or problems in the large intestine. During the procedure, a surgeon inserts a long, thin tube with a camera and light on it (a colonoscope) into the colon to view the large intestine. The surgeon may also remove polyps and samples of tissue for testing during the procedure.

  • How often should you get a colonoscopy?

    Recommendations for how often you should have a colonoscopy vary, depending on your risk factors. Generally, people with UC should have a colonoscopy every one to two years, starting eight to 10 years after the initial onset of UC symptoms.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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