Ulcerative colitis (UC) causes inflammation in the large intestine or colon. The most obvious effects of the disease are symptoms like diarrhea and belly pain. Yet UC can also increase your risk of colorectal cancer.

Read on to find out how UC contributes to colorectal cancer risk, and what you can do to protect yourself.

People with UC are more than twice as likely to get colorectal cancer than those without the disease. UC causes inflammation that can eventually turn cells in the colon lining cancerous.

Your risk of colon cancer starts to increase once you’ve lived with UC for about eight to 10 years. The longer you have UC, the higher your cancer risk rises.

According to a 2001 review of scientific literature, the likelihood of getting colorectal cancer was:

  • 2 percent after living with UC for 10 years
  • 8 percent after 20 years
  • 18 percent after 30 years

By comparison, the risk of getting colorectal cancer in people who don’t have UC is less than 5 percent.

How much of your colon is affected by inflammation also factors into your risk of getting colorectal cancer. People with a lot of inflammation in their entire colon are at the highest risk for colorectal cancer. Those with inflammation only in their rectum are at the lowest risk.

You also need to be alert if you have primary sclerosing cholangitis (PCS), a rare complication of UC. PCS affects the bile ducts, which carry digestive fluid from the liver to the intestine.

PCS causes inflammation and scarring that narrows the ducts. It also increases the risk for colorectal cancer, and the disease may start sooner than eight to 10 years after you’re diagnosed with UC.

Even so, the overall risk of colorectal cancer is still very low. Most people with UC will not get colorectal cancer. But in those who do get colorectal cancer, it may be a more aggressive form that’s harder to treat. That’s why screening is so important.

People with UC should talk to their doctor about getting screened for colorectal cancer. A colonoscopy is the main test used to detect this cancer.

Getting regular colonoscopies can help lower your risk of developing colon cancer or dying from colon cancer. In people who underwent regular screening, the odds of developing colorectal cancer dropped by 42 percent. The odds of dying from this cancer dropped by 64 percent.

A colonoscopy is a test that uses a long, flexible tube with a camera at the end to help your doctor see inside your colon. The test looks for precancerous growths called polyps in your colon lining. The doctor can remove these growths to prevent them from turning into cancer.

Your doctor might also remove tissue samples during your colonoscopy and have them tested for cancer. This is called a biopsy.

Ask your doctor about starting to get regular colonoscopies if it’s been eight years since your symptoms first appeared or you were diagnosed with UC.

The general advice is to have a colonoscopy every one to two years. Yet some people may need to have this test more or less often based on factors like:

  • the age when they were diagnosed
  • how much inflammation they have, and how much of their colon it affects
  • their family history of colorectal cancer
  • whether they also have PSC

Here are a few other things you can do to lower your chances of developing colon cancer and improve your odds of finding it early if you develop it:

  • Take your medications as prescribed by your doctor to keep your UC inflammation under control.
  • See your gastroenterologist for check-ups at least once a year.
  • Let your doctor know if any of your family members had colorectal cancer, or have recently been diagnosed.
  • Eat more fruits, vegetables, and whole grains like brown rice or wheat bread.
  • Limit red meat (such as burgers, steaks, and pork) and processed meats (such as hot dogs, bacon, and sausage), which have been linked to colon cancer risk.
  • Try to walk, ride a bike, or do other exercises on most days of the week.
  • Ask your doctor about taking medications like sulfasalazine (Azulfidine), vedolizumab (Entyvio), or mesalamine. These drugs control UC, and they may lower your risk for colorectal cancer.
  • Avoid alcohol or limit yourself to no more than one drink a day.

Along with getting regular screenings, be alert for these symptoms of colorectal cancer and report them to your doctor right away:

  • a change in your bowel movements
  • blood in your stool
  • stools that are thinner than usual
  • excess gas
  • a feeling of bloating or fullness
  • diarrhea or constipation
  • unplanned weight loss
  • more fatigue than usual
  • vomiting