Lynch syndrome for the gynaecologist

KEY CONTENT: Lynch syndrome is an autosomal dominant condition closely associated with colorectal, endometrial and ovarian cancer. Women with Lynch syndrome are at increased risk of both endometrial and ovarian cancer and should be offered personalised counselling regarding family planning, red flag symptoms and risk‐reducing strategies. Surveillance for gynaecological cancer in women with Lynch syndrome remains controversial; more robust data are needed to determine its effectiveness. Universal testing for Lynch syndrome in endometrial cancer is being adopted by centres across Europe and is now recommended by the National Institute for Health and Care Excellence; thus, gynaecologists must become familiar with testing strategies and their results. Testing strategies involve risk stratification of cancers based on phenotypical features and definitive germline testing. LEARNING OBJECTIVES: To define the pathogenesis of Lynch syndrome and its associated gynaecological cancers. To understand the testing strategies for Lynch syndrome in women with gynaecological cancer. To learn how best to counsel women with Lynch syndrome regarding gynaecological cancer and risk‐reducing strategies to enable informed decision‐making. ETHICAL ISSUES: Offering gynaecological surveillance despite a lack of robust evidence for its clinical effectiveness may falsely reassure women and delay risk‐reducing hysterectomy. Genetic testing may yield variants of unknown significance with ill‐defined clinical implications, which can lead to confusion and anxiety. Genetic testing has implications not only for the individual, but also for the whole family, so expert counselling is crucial.