Endometrial cancer risk factors among Lynch syndrome women: a retrospective cohort study.

BACKGROUND: Lynch syndrome (LS) is associated with a significant lifetime risk of endometrial cancer (EC). There are limited data on factors modifying the EC risk in LS patients. METHODS: The study cohort included 136 LS mutation-positive women. Exposure data were collected by postal questionnaires. Cox regression model was used to estimate the associations between lifestyle, hormonal, reproductive and medical factors and the risk of EC. RESULTS: Increased EC risk was associated with type II diabetes and hypercholesterolaemia in univariable (HR 3.21, (95% CI 1.34-7.78), P=0.009 and HR 2.08, (95% CI 1.11-3.90), P=0.02; respectively) and with diabetes and duration of hormone replacement therapy (HRT) in multivariable analysis (HR 4.18 (95% CI 1.52-11.52), P=0.006 and HR 1.07 (95% CI 1.02-1.13), P=0.010; respectively). CONCLUSIONS: Prevention of diabetes and avoiding long-duration HRT are potential targets for reduction of EC risk in women with LS.