Ulcerative colitis (UC) is a chronic condition that can cause several long-term complications, including an increased risk of colon cancer in some people.

UC is a type of inflammatory bowel disease (IBD). It causes chronic inflammation and the development of sores on the inner lining of the colon.

People with UC may have an increased risk of developing colon cancer, or colorectal cancer, and several other types of cancer.

Read on to find answers to some of people’s most pressing questions about UC and colon cancer.

Multiple studies have found that UC may increase the risk of colon cancer. Different studies report different rates of colon cancer in people with UC, and older studies often report a higher risk of colon cancer than newer studies.

The risk of colon cancer may be particularly high for people who:

  • developed UC at a young age
  • have lived with UC for 20 years or longer
  • have extensive or severe inflammation from UC

The risk of colon cancer may also be higher for those who have:

  • a family history of colon cancer
  • primary sclerosing cholangitis, a condition that causes scarring of the bile ducts
  • other health conditions or lifestyle factors that increase inflammation in the colon

Although more research is necessary, a 2021 review suggests that people with UC may also have a higher risk of certain types of cancer that affect the following parts of the body:

  • small intestine
  • bile duct
  • liver
  • pancreas
  • urinary tract
  • reproductive organs
  • blood
  • skin

The reported percentage of people with UC who develop colon cancer varies from one study to another.

Older studies have found higher rates of colon cancer than newer studies.

A 2001 review found that the overall risk of colon cancer in people with UC was 3.7%.

The risk increased the longer someone lived with UC, with colon cancer affecting:

  • 2% of people with UC after 10 years
  • 8% of people with UC after 20 years
  • 18% of people with UC after 30 years

A 2019 review found that the overall risk of colon cancer in people with UC was lower, at 1.4%.

This review also found that the risk increased the longer someone lived with UC, with colon cancer affecting:

  • 0.7% of people with UC after 1–9 years
  • 1.3% of people with UC after 10–20 years
  • 2% of people with UC after 21–30 years

The different rates across studies may partly reflect differences in research methods, but it is also possible that improvements in UC treatment and colonoscopy screening for abnormal cells have reduced the rate of colon cancer in people with UC.

UC causes chronic inflammation that damages cells in the inner lining of the colon. This can lead to the development of abnormal cells. Experts call this dysplasia.

Over time, the abnormal cells may begin to multiply out of control and develop into colon cancer.

Removing the abnormal cells can reduce the risk of colon cancer.

People with UC can potentially reduce their risk of colon cancer by:

  • getting colonoscopy screening
  • getting treatment for UC
  • maintaining a healthy lifestyle

Colonoscopy screening

Colonoscopy screening can help doctors detect and remove abnormal cells before they develop into colon cancer. If colon cancer has already developed, colonoscopy screening can help doctors detect it early, when treatment is most effective.

The American Cancer Society (ACS) recommends that, in general, people start colonoscopy screening at least 8 years after getting a diagnosis of UC. A doctor may recommend follow-up screenings every 1–3 years, depending on a person’s risk factors and the results of previous screenings.

If someone has primary sclerosing cholangitis, their doctor may recommend earlier and more frequent colonoscopy screenings.

UC treatments

Multiple treatments are available to reduce inflammation and manage symptoms of UC. Although more research is necessary, reducing inflammation through treatment might reduce the risk of colon cancer. Some treatments may also directly target cellular mechanisms that play a role in the development of cancer.

A 2022 review suggests that the following UC treatments may help lower the risk of colon cancer:

  • 5-aminosalicylic acid compounds
  • thiopurines, including azathioprine and mercaptopurine
  • tumor necrosis factor-alpha inhibitors
  • Janus kinase (JAK) inhibitors

However, other studies have found no effect of these treatments on colon cancer risk. The quality of available evidence on UC treatments and colon cancer risk is low.

More research is necessary to learn how different UC treatments affect colon cancer risk.

Lifestyle changes

Certain lifestyle habits might help reduce the risk of colon cancer in people with and without UC.

Where applicable, the ACS encourages the following:

  • avoiding or limiting alcohol
  • avoiding or quitting smoking
  • making efforts to maintain a moderate weight
  • getting regular exercise and limiting sedentary time
  • eating a diet rich in fruits, vegetables, and whole grains and low in processed and red meats

Some studies suggest that taking certain vitamin and mineral supplements might also reduce the risk of colon cancer, but more research is necessary.

UC causes chronic inflammation in the colon, which may increase the risk of colon cancer. The risk of colon cancer appears to be particularly high for people who have had UC for decades and those who have extensive or severe inflammation in the colon.

Regular colonoscopy screening is important for detecting early signs of colon cancer, including abnormal cells that may develop into cancer. Certain treatments for UC and healthy lifestyle habits might also reduce the risk of colon cancer, although more research is necessary.

A person with UC can talk with a doctor to learn more about their risk of colon cancer and how to manage it.