The Link Between Crohn's Disease and Colon Cancer

The scary part? Your risk of colon cancer is higher if you have Crohn's. But there’s a lot you can do to lower your odds.

by Sheila M. Eldred Health Writer

Editor's Note: This story is part of a new series on HealthCentral called "Get Your Ph.D.!", which is geared toward people who've got the basics of their condition down and want to up their expertise. Who's ready to go pro?!

Allison Rosen was used to weird bowel symptoms. After all, the 39-year-old from Houston has lived with Crohn’s disease since she was 12. But after a month of weirder-than-usual symptoms, including going more often and seeing more blood in her stool, she decided she must have a blockage in her small intestine.

So she scheduled the annual scope she’d been putting off because she was young and busy and “cancer was the last thing on my mind.” She’d had a clean colonoscopy just a year and a half earlier. And she certainly wasn’t expecting the results: a 13-centimeter tumor that turned out to be stage 2 cancer (in colon cancer, stage 2 means that the cancer has spread beyond the innermost layers of the colon).

Rosen’s diagnosis may sound surprising, but it’s more common than you probably think. And for people who’ve been living with Crohn’s for years, it’s especially critical to take the risk seriously. That’s because the odds of colon cancer not only increase the longer you have Crohn’s, but the cancers that do develop tend to be more aggressive, says Anton Bilchik, M.D., a surgical oncologist and chief of gastrointestinal research at John Wayne Cancer Institute at Providence Saint John’s Health Center in Santa Monica, CA.

Exactly how much does Crohn’s up your risk of colon cancer? The findings in studies have varied, ranging from a 60% increased risk compared to people without inflammatory bowel disease to as much as 20 times higher, says Dr. Bilchik. What is consistent? The longer you’ve been living with Crohn’s, the more vigilant you need to be.

No one knows for sure why people with Crohn’s are so much more likely to develop colon cancer than the average person, but research suggests that the chronic inflammation associated with Crohn’s disease may play a significant part, according to a study in Cancer Research Prevention. Not only does that inflammation literally damage the cells lining the colon, but that constant attack may interfere with the body’s ability to recognize—and neutralize—rogue cancer cells, says Ashkan Farhadi, M.D., a gastroenterologist at MemorialCare Orange Coast Medical Center and director of MemorialCare Medical Group’s Digestive Disease Center in Fountain Valley, CA. The reason?

What to Know About Crohn’s and Colon Cancer Screening

Folks without Crohn’s can put off colon cancer screening until age 45, according to recommendations from the American Cancer Society. Not so for people with Crohn’s. While guidelines vary, doctors agree that this group needs earlier and usually more frequent colonoscopies—even if they’re not currently having clinical symptoms, Dr. Farhadi says. That usually means every one-to-two years for people who’ve been living with Crohn’s for eight years or longer, according to the Crohn’s and Colitis Foundation.

And in Crohn’s patients, the colonoscopy should include the ileum (the third portion of the small intestine), sometimes called an ileocolonoscopy. And yes, the screening has to be a colonoscopy if you have Crohn’s, he says. “We’re looking for a certain type of cancerous lesion that’s a little bit different from what we’re looking for in normal individuals—and it can only be found by colonoscopy.”

Still, it’s an easy screening test to put off. John Fritz, a 45-year-old in Walnut Creek, CA, wishes he hadn’t. “Had I not wasted two and a half years, I’d have been in a better situation,” he says.

During that time, he figured he’d be able to control the bleeding, diarrhea, and pain he was experiencing by locking down his diet—until one day, he was cooking dinner when a stabbing pain forced him to grab onto the counter and lean on it. The pain gradually passed, and he could stand again. He’d never felt that kind of pain during his 14 years of Crohn’s. He immediately scheduled a scope and found out that he had stage 3C (late stage) cancer.

Again, this is exactly why it’s important to stay on top of your symptoms and your screenings. Colon cancer does tend to be more aggressive in those with Crohn’s, even though the signs—weight loss, diarrhea, and bleeding—may seem like just a blip on your own bowel radar, Dr. Farhadi says.

As a patient advocate active in the Crohn’s and colon cancer communities’, Rosen agrees: “Since we are at higher risk, we need to really pay attention when our bowel habits change or we start to experience weird side effects. As soon as anything seems even a little off to talk with your GI doctor about your symptoms and get a colonoscopy.”

What to Know About Crohn’s and Colon Cancer Treatment

Here’s where the news gets better for Crohn’s patients: Sometimes, the treatment for colon cancer relieves your Crohn’s disease symptoms.

Ever since Rosen had a permanent ostomy, her Crohn’s has been in remission. There’s a chance it could resurface, since Crohn’s can involve the whole digestive tract, but it’s been more than three years and so far, so good.

Of course, removing your colon a very tough decision, even when you’re facing a cancer diagnosis. Rosen initially chose a J-pouch, which involves removing the colon and rectum and creating a new “pouch” from the intestine to hold stool; it allows patients to continue using the bathroom as usual. But ultimately, her J-pouch failed.

“I was in and out of the hospital with horrible inflammation and pouchitis, and they think it was as a result of my Crohn's attacking the J-pouch,” she says. “When my doctor took my colon out, he said it basically fell apart in his hands and there was no hope for a simple resection. Essentially I should have had a colostomy or ileostomy from the start as it would have helped me avoid me future surgeries and hospital stays.”

What You Need to Know About Colon Cancer Prevention When You Have Crohn’s

No doubt you’ve wished for a magic pill or cure as a Crohn’s patient. Unfortunately, there’s no sure-fire way to prevent colon cancer, either.

However, there are plenty of lifestyle changes that could make a difference—and, even if they don’t end up preventing colon cancer, they’ll still improve your quality of life. Yes, we’re talking exercise, diet, sleep, and stress management. In fact, all the non-medicinal tools you probably use to keep your Crohn’s in remission are also helpful in reducing your risk of cancer, Dr. Farhadi says. Research he’s done shows meditation can be as important as medication in managing inflammatory bowel disease (IBD). (But taking your medication as instructed is also important, he adds!)

Reducing the amount of red and processed meat you eat can help keep your cancer risk in check as well. Maintaining your Crohn’s in remission allows you to eat more nutrient-rich whole foods, which will help you avoid obesity—and there’s a direct association between obesity and colon cancer, Dr. Bilchik explains.

Dr. Bilchik also expects researchers to explore a more direct link between exercise, cancer reduction, and Crohn’s patients. His reasoning: If inflammation from Crohn’s leads to cancer, and exercise is anti-inflammatory and improves the immune system, logic would say that exercise should lower cancer risk.

Hope for the Future

A cancer diagnosis is always devastating, but there IS hope.

The standards of care for Crohn’s disease are shifting, Dr. Farhadi says. In the past, the disease was considered in remission as long as you were symptom-free. But that meant that inflammation could be lingering under the surface. “Now we’re changing the goal so that you also have to be inflammation-free,” he says. Given the connection between inflammation and cancer, he suspects the rates of cancer in Crohn’s patients could drop.

And Dr. Bilchik says the number of new biologic drugs, which can enhance the body’s immune system and can be used in addition to surgery, is reassuring. These drugs tamp down inflammation at the source and may help prevent some of the damage that can contribute to cancer.

In the meantime, Fritz says that his background of Crohn’s actually prepared him for cancer.

“For most people, cancer turns their world upside down,” he says. “But I was used to having accidents at the worst possible times; I was used to being in pain.” He knows the road he’s on isn’t going to be easy, but there is some comfort in the familiarity.

As for Rosen, she’s gone surfing, rock-climbed, and traveled the world—all since her cancer diagnosis and ostomy: “I was always adventurous before the ostomy—and thought I would never be able to be as active as before—but I am even more active now and willing to try new things.”

  • Colon Cancer Risk and Causes in Crohn’s: Cancer Prevention Research. (2016). “Colorectal Cancer and Dysplasia in Inflammatory Bowel Disease: A Review of Disease Epidemiology, Pathophysiology, and Management.”
  • More Risk Stats: Gastroenterology. (2012). “Incidence and Mortality of Colorectal Adenocarcinoma in Persons With Inflammatory Bowel Disease From 1998 to 2010.”
  • Inflammation and Colon Cancer: Heredity Cancer in Clinical Practice. (2019). “Colorectal Carcinoma in the Course of Inflammatory Bowel Diseases.”
  • Crohn’s and Colon Cancer Basics: Crohn’s and Colitis Foundation. (n.d.) “The Risk of Colorectal Cancer in Crohn’s Disease and Ulcerative Colitis Patients.”
  • Screening Guidelines: American Cancer Society. (2018). “American Cancer Society Guideline for Colorectal Cancer Screening.”
  • Meditation: Digestion. (2014). “A Randomized Controlled Trial of Mindfulness-Based Stress Reduction to Prevent Flare-Up in Patients with Inactive Ulcerative Colitis.”
  • Diet and Colon Cancer: American Institute for Cancer Research. (2016). “Diet-Cancer Experts Welcome WHO Report on Meat and Cancer.”
Sheila M. Eldred
Meet Our Writer
Sheila M. Eldred

Sheila Mulrooney Eldred is a graduate of Columbia’s School of Journalism and a former newspaper reporter. As a freelance health journalist, she writes about everything from life-threatening diseases to elite athletes. Her stories have appeared in The New York Times, Nature, FiveThirtyEight, Pacific Standard, STAT News, and other publications. In her spare time, she and her family love running, cross-country skiing, and mountain biking in Minneapolis.