Frequently Asked Questions

What is the risk of cancer in hereditary nonpolyposis colon cancer (HNPCC)?

There is a 68% to 75% risk of colorectal cancer in HNPCC by age 65. The median age of diagnosis is 45 years but it can be as low as the early 20s. There is a 30% risk of developing a metachronous colorectal cancer at 10 years after limited resection and 50% risk after 15 years. HNPCC mutation carriers also exhibit a 30% to 39% cumulative risk of endometrial cancer by age 70; first-degree relatives have a 15% risk. Additionally, there is a 3.5 times higher risk of ovarian cancer in women with HNPCC.

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Mara, G, Boland, CR (1995). Hereditary nonpolyposis colorectal cancer. Journal of the National Cancer Institute, 87, 1114-1125.

Aarnio, M, Mecklin, J-P, Aaltonen, LA, et al (1995). Lifetime risk of different cancers in hereditary non-polyposis colorectal cancer syndrome. International Journal of Cancer, 64, 430-433.

Watson, P, Lynch, HT (1993). Extracolonic cancer in hereditary nonpolyposis colorectal cancer. Cancer, 71, 677-685.