Colon Polyps and Your Cancer Risk

Polyps in colon, artwork
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Virtually all colon cancer develops from adenomatous polyps in the colon, generally referred to simply as colon polyps. Polyps don't always become cancerous, but your risk of developing cancer increases with the number and size of colon polyps you have. A personal or family history of polyps puts you at higher risk for colon cancer as well.

Personal History of Colon Polyps

Approximately 1 percent of polyps with a diameter less than a centimeter are cancerous. If you have a single polyp of that size, the American Cancer Society (ACS) recommends that a doctor removes it and that you receive another colonoscopy three to six years later. (Without any polyps, your next test would be 10 years later.)

If you have more than one polyp or the polyp is bigger than a centimeter, you're considered at higher risk for colon cancer. After these colon polyps are removed, you'll probably be asked to get another colonoscopy in three years. The doctor is also likely to test the polyp, since up to 50 percent of polyps greater than 2 centimeters (about the diameter of a nickel) are cancerous.

Family History of Colon Polyps

When it comes to polyps and colon cancer risk, family history is important. It's probably not the most comfortable conversation to have, but you should find out if your parents, siblings, or children have ever had any colon polyps. If they have, you're no longer in the average-risk category for colon cancer.

If two or more first-degree relatives have had colon polyps, the ACS recommends that you receive your first colonoscopy at age 40, or 10 years before the age when your relative's polyp was found—whichever is earlier. If both of your parents had polyps, for example, have a colonoscopy at 40 instead of 50.

Another family scenario that increases risk: having any first-degree relative discover a colon polyp before age 60. If you have a parent or sibling with a polyp, the same higher-risk recommendations apply. For example, if your brother had a polyp removed when he was 45, the ACS says you should get a colonoscopy when you're 35.

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