How IBD affects your colorectal cancer risk

March is National Colorectal Cancer Awareness Month, so it’s a good time to brush up on your knowledge about this type of cancer that’s linked with inflammatory bowel disease (IBD).

IBD and colorectal cancer

Colorectal cancer (CRC) is a type of cancer that originates in the colon or rectum – and having IBD may increase your risk of CRC.

“Inflammation of the large intestine over a long period of time can increase the risk for pre-cancer or cancer of the colon,” says David T. Rubin, MD, professor of medicine and chief of gastroenterology at the University of Chicago, and chair elect of the national scientific advisory committee for the Crohn’s and Colitis Foundation. “That risk is higher in people who have ulcerative colitis, which by definition, is inflammation of the large intestine,” explains Dr. Rubin.

However, Crohn’s disease can affect any part of the GI tract, so the risk of colorectal cancer depends on where the Crohn’s is located. “You have to have inflammation in the large intestine to fall under the category of being at risk,” says Rubin. If you are unaware of where your IBD is located and what your cancer risk may be, you should discuss this important issue with your doctor.

Know your risk factors

The good news: There are ways to reduce your risk of developing colorectal cancer—or to catch it early if it does appear. The first step is to become familiar with your individual CRC risk factors. This may include:

  • How long you’ve had IBD: Risk of developing CRC increases after living with your condition for 8 to 10 years
  • How large the affected area is: Risk of developing CRC is higher when more of the large intestine (colon) is affected by IBD
  • How much inflammation you’ve had: Risk is higher if you’ve had more severe inflammation over a longer period of time

It’s also important to consider:

  • Whether or not you have a family history of CRC or personal history of adenoma type colon polyps
  • Whether or not you also have inflammation in the liver—a condition called primary sclerosing cholangitis, or PSC

“PSC is such a strong risk factor that we recommend people who have it start getting screened for colon cancer right away,” adds Rubin. If you don’t know your IBD or other pertinent medical history well enough to assess your risk, you should ask your doctor to help you.

Regular screenings help prevent colorectal cancer

The other step you should take to help reduce colorectal cancer risk is to undergo surveillance colonoscopies. This screening test can help detect early signs of CRC which can lead to earlier diagnosis and treatment and improved outcomes.

“Even if you’re in remission, that doesn’t mean your CRC risk is gone—you need to make sure you have your regular colonoscopies,” says Rubin. Your doctor will help determine how often you may need this test. It could range from once a year to once every five years depending on your IBD history.

It’s essential to undergo these screenings with a provider that knows exactly what to look for. “Make sure the person doing the exam is using the latest equipment, and when they find something they’re not sure about, they refer you to an expert,” says Rubin.

When you have IBD, your only option for colorectal cancer screening is a colonoscopy. “The stool tests people see advertised on TV, blood tests that people are working on in research labs, and virtual colonoscopies or CT scans—those things are only for non-IBD patients,” explains Rubin.

So be sure to work out a routine colonoscopy schedule with your care team—which may vary based on your specific condition—and stick with it.

Bottom line: CRC is not a given

“When someone is diagnosed with colitis, they go online, and one of the first things they read is that they’re going to get colon cancer,” says Rubin. “It’s very scary—and it’s very inaccurate. The majority of people will not get colon cancer.”

While colorectal cancer risk can be increased in people with IBD, it’s important not to panic. “Between controlling the disease better and doing surveillance colonoscopies, we’ve driven the rates of CRC in IBD down significantly, almost to the general population (those without IBD) rates,” says Rubin.

The best thing you can do to help prevent CRC is to work with your care team to control your IBD and achieve remission—and get routine colonoscopies to screen for colon cancer. If you notice any change in your bowel symptoms, be sure to work with your doctor to determine the cause and get your IBD in control.

Medically reviewed by Matthew Hamilton, MD

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