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Most people who develop colon cancer do not have a known family history of the condition. However, in approximately one out of every three cases, at least one family member is known to have had colon cancer as well. Therefore, if you are aware that this type of malignancy runs in your family, you might be wondering what your chances are of developing it yourself.

How family history can affect colon cancer risk

Studies show that people who have at least one first-degree relative – a parent, sibling or child – who has had colon cancer (or precancerous adenomatous polyps) have an elevated risk of developing the condition themselves. The risk increases if the relative was diagnosed at age 45 or younger or if more than one first-degree relative was diagnosed.

The exact role that family history plays in colon cancer risk is not yet well understood. Scientists believe that colon cancer may “run in families” due to inherited gene mutations, shared environmental factors or a combination of both.

How to protect yourself

If you have a family history of colon cancer or adenomatous polyps, you are encouraged to talk with your doctor about prevention and screening. For instance, you may be advised to have your first colonoscopy or other colon cancer screening test before you reach age 50, the age at which colon cancer screening typically begins for individuals at average risk. Additionally, if you’ve been diagnosed with colon cancer or adenomatous polyps, it’s important for you to tell your relatives so that they can inform their doctors, who in turn will consider that information when providing colon cancer screening recommendations.

If you’d like to discuss your individual colon cancer risk profile with a specialist in the Gastrointestinal Oncology Program at Moffitt Cancer Center, you can request an appointment by calling 1-888-663-3488 or completing a new patient registration form. We do not require referrals.