IBS and Colon Cancer

During the diagnosis process of determining that a patient’s symptoms are caused by irritable bowel syndrome (IBS), some of the tests are used to rule out any possible colon cancer. Colon cancer rarely causes typical IBS symptoms, unless additional symptoms of weight loss, blood in the stools, or abnormal blood tests are also present.1

While the symptoms of IBS are frustrating and can impact your normal activities, having IBS does not put you at greater risk of developing colon cancer or other digestive disorders. IBS does not cause physical damage to your colon. However, it does not protect you from getting colon cancer either. Because IBS symptoms can fluctuate, it’s important to know the “alarm” symptoms – those symptoms that indicate that additional testing is needed to determine the cause.2

Alarm Symptoms

Alarm symptoms are not caused by IBS. Rather, they are symptoms or signs of another disease that physically damages the gut and require additional investigation. Sometimes, these symptoms turn out to be not alarming at all. For example, a small amount of bright red blood may be caused by a hemorrhoid or small tear. Regardless, any of these alarm symptoms should be brought to the attention of your medical professional for evaluation:

  • Blood in the stool
  • Nighttime symptoms that awaken you
  • Unintentional weight loss
  • Change in typical IBS symptoms, such as a new and different pain
  • Family history of other GI diseases, including cancer, inflammatory bowel disease, or celiac disease2

Higher Risk for Colon Cancer

There is no single cause of colon cancer. Nearly all colon cancers begin as noncancerous (benign) polyps, which later develop into cancer. These polyps can be detected and removed during a colonoscopy. People with the following characteristics are at a higher risk of colon cancer:

  • Those older than 60
  • African American or of Eastern European descent
  • Those who eat a lot of red or processed meats
  • Those who have colorectal polyps
  • Those who have inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis
  • Those with a family history of colon cancer
  • Those with a personal history of breast cancer
  • Those who smoke cigarettes
  • Those who drink alcohol3


It is comforting to know that IBS does not cause colon cancer, or put you at greater risk.1 Colon cancer is a common cancer that most often occurs in people over the age of 50, and most people are advised to get a screening test, such as a colonoscopy, beginning at age 50. Those with additional risk factors, especially a family history of colon cancer, are generally screened at an earlier age. Colon cancer is very treatable when caught at its earliest stages, and screening can catch and treat polyps before they become cancer.4

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Written by: Emily Downward | Last reviewed: June 2016.