September 14, 2012
Dear Mayo Clinic:
Last month I had a few polyps removed during a colonoscopy. Does this mean I am more likely to get colon cancer? My physician told me it was nothing to worry about, but I thought having a polyp meant cancer is inevitable.
Having colon polyps raises your risk for developing more polyps in the future. It does not necessarily make you more likely to get colon cancer. If left untreated, some colon polyps do develop into cancer. But that's not always the case. Regular colonoscopies can help your doctor find and remove polyps when they are small, before they cause any problems.
Colon polyps are clumps of cells that form in the lining of the colon. They grow slowly over time and typically do not cause symptoms, particularly when they are small. In time, however, some large polyps may cause bleeding into the colon. In addition, depending on where it is located, a large polyp can also block the colon, leading to problems such as abdominal pain, severe constipation, nausea and vomiting.
Polyps are most common in people older than 50, and may be more common in smokers, people who are overweight and those who eat a low-fiber, high-fat diet. People with a family history of colon polyps are also more likely to get polyps than those who do not have the same history.
Small colon polyps are harmless. But over time, some do grow and become cancerous. There is no way to tell the difference between polyps that will turn into colon cancer and polyps that won't by simply looking at them. The polyps need to be removed and analyzed under a microscope in a laboratory. If your doctor told you that the polyps removed from your colon were not worrisome, it is likely that they were removed early, before they had a chance to grow and become cancerous.
One of the best ways to find colon polyps is with colonoscopy. During this exam, a long, flexible tube, called a colonoscope, is inserted into the rectum. A tiny video camera at the tip of the tube allows your doctor to view the inside of the colon. If your doctor finds a small polyp, it can usually be removed during the colonoscopy. For larger polyps, a tissue sample, or biopsy, may be taken during a colonoscopy for further examination. If a polyp cannot be completely removed during a colonoscopy, it may need to be surgically removed later.
For people age 50 and older who do not have any risk factors for colon cancer other than age, colonoscopies are typically recommended once every 10 years, beginning at age 50. People who have additional risk factors may need colonoscopy more often than that and start having them at a younger age. If you have had one or more polyps removed, you are more likely to get additional polyps in the future. It is important therefore to follow your doctor's recommendation for getting colonoscopies, so any new polyps can be caught quickly.
Regular colon cancer screening with colonoscopy significantly lowers your risk of developing colon cancer.
ā John Pemberton, M.D., Colon and Rectal Surgery, Mayo Clinic, Rochester, Minn.