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Family History and Risk for Colon Cancer

Family History and Risk for Colon Cancer

Question
Dear OncoLink "Ask the Experts,"
I am 31-year-old male. I have been reading a lot about hereditary colon cancer due to some recent symptoms of lower right-sided abdominal cramps. My family history is both grandparents on fathers side diagnosed at age 50-55. Great grandfather on father's side diagnosed at 75. Mom has no colon cancer history. So far my father and his siblings (4 total / ages 45-55) are free of the disease and free of polyps. I had a flex-sigmoid at age 29, which was clear. Would I constitute a possible or likely "familial" situation?  
Thank you so much.


Answer
Anil Rustgi, MD, Chief of Gastroenterology and the T. Grier Miller Associate Professor of Medicine and Genetics at the University of Pennsylvania, responds:

The lifetime risk of colon cancer is increased for first-degree (parents, sibling, children) relatives and to a lesser extent for second-degree relatives (grandparents, aunts/uncles), although still increased. Thus, you are at somewhat increased risk. Although it is good that your father and aunts/uncles have yet to manifest polyps or cancer. You should have a screening colonoscopy at some point, and if that is normal, your gastroenterologist can determine the frequency.