Warning: Young adults CAN have colon cancer, and a diagnosis of IBS without a colonoscopy can cost you your life.

The symptoms of irritable bowel syndrome and colon cancer have significant overlap.

“IBS is much more common than colorectal cancer, and has a well-recognized pattern of symptoms such as bloating, distension, cramps, abdominal pain, diarrhea and/or constipation,” says Joseph Weiss, MD, a board certified gastroenterologist and clinical professor of medicine at the Medical School, University of California, San Diego.

Though IBS never causes blood in your stools, keep in mind that the absence of blood does not rule out colon cancer.

Colon cancer doesn’t always cause blood in one’s BMs by the time it causes other symptoms that mimic those of IBS.

You should never faithfully believe in an IBS diagnosis unless other tests have ruled out cancer.

In fact, it’s not just colon cancer that can mimic the symptoms of IBS. Ovarian cancer, too, can pull this cruel stunt.

Have you been diagnosed with IBS but have not seen a gynecologist? You probably don’t have ovarian cancer if you’re younger.

But “probably” isn’t as reassuring as “definitely.” Younger women can get ovarian cancer.

If you’re a man who’s been diagnosed with IBS, have you had a colonoscopy? A negative colonoscopy will bring great peace of mind.

Both men and women, even younger, need to get that colonoscopy—also because it can reveal the great mimicker of IBS: microscopic colitis.

The symptoms are nearly identical, but the treatments are very different. 

“Other diagnoses must be considered,” says Dr. Weiss, “such as inflammatory bowel disease [microscopic colitis, ulcerative colitis and Crohn’s disease), celiac disease with gluten sensitivity, small-intestinal bacterial overgrowth, intestinal infections, parasites and many others.”

In addition to not causing any internal bleeding, IBS also does not cause weight loss (though inflammatory bowel disease can).

Though less likely to occur in people under 50, a delayed diagnosis of colon cancer is “less forgiving,” says Dr. Weiss.

Nearly 22% of all yearly colon cancer diagnoses in the U.S. are in people under age 55, says the National Cancer Institute Surveillance, Epidemiology and End Results Program. People between 35 and 44 account for 4.6% of cases.

Yes, that’s a pretty small number, but it’s meaningless to younger adults whose colon cancer was initially misdiagnosed as IBS.

Dr. Weiss believes that the reason for the increase in colon cancer diagnoses is related to SAD: standard American diet – a diet laden with processed foods including deli and luncheon meats.

Plus, a sedentary lifestyle likely contributes. Most people still do not, despite ongoing promotion of it, engage in consistent, structured cardiovascular and weight-bearing exercise.

“The beginning age for colon cancer screening has been reduced to 45 in those at average risk,” says Dr. Weiss.

Screening for younger adults is not recommended unless they have a higher risk, such as a parent who was diagnosed with the disease before age 65.

Diagnosed with IBS and in Your 20s or 30s?

• Have a fecal immunochemical test that will detect blood in your stools.

• Have a blood test for inflammatory bowel disease.

• Have a blood test for celiac disease.

• Get a genetic screening for Lynch syndrome (a genetic predisposition to colon cancer) if you have a family history of colon cancer.

• Follow your physician’s recommended treatment for the IBS.

• Pay very close attention to your symptoms; track them; there are various phone apps for this.

Dr. Weiss explains that if there’s no symptom relief despite taking remedial measures, “the diagnosis should be reconsidered.

“Colonoscopy would more likely be diagnostic of an inflammatory bowel disease [e.g., microscopic colitis], but cancer must remain a consideration and is another reason that would justify arriving at a definitive diagnosis.”

Dr. Weiss is the author of Got Guts! A Guide to Prevent and Beat Colon Cancer. He has also presented numerous presentations on various health topics.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  



Top image: Shutterstock/Dragana Gordic