The results of gynecologic surveillance in families with hereditary nonpolyposis colorectal cancer

•EC surveillance should only be targeted at MMR mutation carriers starting from the age of 35–40.•Research into attitudes toward screening is needed to clarify the low attendance at gynecological surveillance in MMR-mutation carriers.

ObjectiveWe aimed to estimate the incidence rate of endometrial cancer (EC) and to evaluate the results of EC-surveillance in hereditary nonpolyposis colorectal cancer (HNPCC) families.MethodsAll at-risk women recommended for EC-surveillance by the HNPCC-register—2959 women (19,334 women years)—were included. Data on EC-surveillance were available for 871 women (6894 women years), who had performed 1945 surveillance visits. The average surveillance period was 7.9 (range 0.1−21.7) years and 46% of the women had had less than 3 years between their visits.ResultsDuring 19,334 women years, 60 women with gynecological malignancies or premalignancies were diagnosed. Thirty-nine women had EC. Of these, 31 were from families with identified MMR gene mutations with the median age at diagnosis of 54 (39–83) years (Incidence Rate, IR = 0.63 per 100 women years) and four women from each Amsterdam (AMS)-positive and AMS-like families (median age 64 (55–73) years, IR = 0.06 and 0.05 per 100 women years, respectively, p < .0001).Among the 871 surveilled women, 13 EC were found: 7/13 cases were diagnosed by surveillance examination—two as prevalent cancers, diagnosed at the first visit—and 6/13 based on symptoms. In addition, five complex atypical hyperplasias and four ovarian cancers (OCs) were diagnosed. All these women were MMR mutation carriers.ConclusionBased on 19,334 women years of EC-surveillance, our analysis provides a thorough estimation of the EC risk in women with an MMR mutation, or suspected of having Lynch syndrome. We conclude that EC surveillance should only be targeted at MMR-mutation carriers.