What anyone with ulcerative colitis needs to know about colorectal cancer
It’s more complicated than you might think.
Having a chronic illness like ulcerative colitis affects your health in so many ways, from the daily issues, like terrible pain, to the big picture, like an increased risk of colorectal cancer. The connection between ulcerative colitis and colorectal cancer can be scary and confusing, but it’s an important one to understand. Here’s what you need to know about it.
What is ulcerative colitis?
You probably already know this part, but a quick refresher doesn’t hurt. As a form of inflammatory bowel disease (IBD), ulcerative colitis creates inflammation in the gastrointestinal (G.I.) tract. This can lead to irritation and swelling as well as ulcers (sores) along the inner lining of the colon or the large intestine, the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) explains.
The aim of ulcerative colitis treatment is long-term remission (periods of being symptom-free). According to the NIDDK, most people do achieve weeks or years of remission with a combination of medications, dietary modifications, and/or surgery.
How does ulcerative colitis affect colorectal cancer risk?
We’re about to get into the more nerve-wracking information here, so before we do, let’s be really clear: Having ulcerative colitis is in no way a guarantee that you’ll get colorectal cancer. But the condition does increase your risk of developing cancer in your colon and rectum (the last section of your colon). To make things less confusing, even though ulcerative colitis increases your risk of both colon cancer and colorectal cancer, we’ll refer to colorectal cancer throughout since it’s more encompassing.
Now, let’s talk about that increased risk. Overall, people who have chronic IBD (either ulcerative colitis or Crohn’s disease) are nearly twice as likely to develop colorectal cancer than the general population, according to the American Cancer Society (ACS) Colorectal Cancer Facts & Figures 2017-2019 Report. “It’s important to recognize that the risk varies tremendously based on the type, severity, and location of the colitis,” Paul Oberstein, M.D., director of the Gastrointestinal Medical Oncology Program at NYU Langone’s Perlmutter Cancer Center, tells SELF. (Colitis means inflammation of the colon.)
People with colitis affecting the entire colon are at greater risk of these cancers, Dr. Oberstein says. On the other hand, people with colitis on only certain portions, like the left side, are generally considered to be at moderate risk, and those who have colitis only in the rectum are at lower risk, possibly similar to that of people without ulcerative colitis, according to some studies.
Whether or not the inflammation is prolonged also impacts risk. “The more severe or persistent the inflammation is…the higher the risk of colorectal cancer is going to be,” Yinghong Wang, M.D., Ph.D., M.S., a gastroenterologist at MD Anderson Cancer Center, tells SELF.
A widely cited 2001 meta-analysis of 116 studies published in Gut found that the lifetime incidence of colorectal cancer in people with ulcerative colitis was 3.7%. But this number changed dramatically when researchers looked at studies that also reported the duration of disease before colorectal cancer diagnosis. A disease duration of 10 years corresponded with a 2% chance of getting this cancer; 20 years, an 8% chance; and 30 years, an 18% chance.
Experts don’t fully understand the connection between these conditions. “The exact mechanism on a molecular level is not quite clear yet,” Dr. Wang says, noting that there is ongoing research in this area. But the pathway by which gene mutations occur is different in people with ulcerative colitis than in people without IBD, Dr. Wang says, and it’s likely that genetic factors are involved. What we do know is that ongoing or untreated IBD can lead to dysplasia, the formation of cells in the colon or rectum that aren’t normal-looking but aren’t cancerous yet—though they can become so over time, the National Cancer Institute explains. That’s why long-term remission may lower your odds of getting colorectal cancer.
Of course, “some of the [risk] factors you cannot change,” Dr. Wang says, like how far-reaching your disease was at the time of diagnosis, your age (colorectal cancer is more common after age 50), and your family history. (Surgically removing the colon is the sole way to completely nullify the risk, the NIDDK says.) Beyond that, “The only thing we can change is your active disease status—whether we can offer you effective treatment to control the inflammation,” Dr. Wang says.
People with ulcerative colitis need to be screened for colorectal cancer more thoroughly and more often.
The ACS recommends that people at average risk of developing colorectal cancer start getting regular screenings at age 45. Depending on the specific type of screening, regular might mean every year (like for some stool-based tests), or even every 10 years (like with a colonoscopy, for which the doctor inserts a scope into your rectum to get a good look at the inside of your colon). “A colonoscopy is the best tool to detect early cancer because we can directly look at the colon and find a suspicious lesion,” Dr. Wang says.
People with IBD, on the other hand, are generally advised to get colonoscopy screenings (instead of any other exam) every one to two years starting at an earlier age than 45, but the exact guidelines depend on the specifics of your case.
“We need to individualize the…screening based on the course and extent of the patient’s colitis,” Dr. Oberstein says, as well as any additional risk factors. For instance, people with a family history of colorectal cancer may need yearly screening, while people in remission who have clear screenings for several years may be able to space them out more, Dr. Wang says, adding that it’s key to have an ongoing discussion with your doctor about the right timeline for you.
In any case, colonoscopies for people with ulcerative colitis are typically more involved and require greater expertise than screenings for somebody at average risk, Dr. Oberstein says. Not only are people with colitis at an increased risk for colorectal cancer, but the lesions themselves can also be subtler and harder to see, Dr. Oberstein explains. On top of that, surrounding inflammation can make abnormal lesions even more difficult to distinguish, Dr. Wang says.
To compensate for that, doctors often use “special techniques that are more sensitive” than the standard colonoscopy when examining someone with ulcerative colitis, Dr. Oberstein says. The most common is a chromoendoscopy, which uses dye to help identify subtle lesions in the colon lining better than just using light, Dr. Wang says. Another technique is biopsying, or taking tiny tissue samples to look for cancer in them.
Although screenings won’t reduce your risk of getting colorectal cancer, as the NIDDK points out, early detection and diagnosis may improve your odds of successful treatment and recovery. “The risk of [colorectal] cancer is always there, and you can’t ignore it,” Dr. Wang says. But timely screening can make a big difference, he adds, “because there are a lot of treatment options you have when you detect it early.”