Endoscopic Surveillance in Hereditary Nonpolyposis Colorectal Cancer

Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited cancer predisposition syndrome with a greatly increased risk of colorectal cancer and some other cancer types, especially endometrial cancer in women. The predisposition is caused by a pathogenic mutation in one of several DNA mismatch repair genes, eg, MLH1, MSH2, or MSH6. Identification of HNPCC families and successful detection of the specific mutation for the individual family enables predictive genetic testing for the at-risk members in the family. Mutation-negative family members can be relieved from increased cancer risk, whereas mutation-positive members should be enrolled in endoscopic surveillance for prevention or early detection of colorectal cancer. Regular colonoscopies reduce the colorectal cancer incidence to less than half, prevent colorectal cancer deaths, and improve overall survival compared with nonsurveillance. The optimal surveillance interval lies between 1 to 3 years beginning from the age of 25, at the latest. For women, endometrial vacuum biopsies are commonly recommended possibly added by endovaginal ultrasound examination even though firm evidence supporting this is lacking.