Implementation of tumor testing for lynch syndrome in endometrial cancers at a large academic medical center

Lynch syndrome (LS) is a hereditary condition that increases the risk for endometrial and other cancers. Recognizing women at risk for LS based on personal/family history is burdensome and imprecise. Tumor testing using microsatellite instability (MSI) testing and immunohistochemistry (IHC) for mismatch repair protein expression can be an effective strategy for identifying potential LS in patients presenting with colorectal or endometrial cancer. Here we describe our experience implementing a screening program for endometrial cancers.

Endometrial cancers diagnosed ≤50 years or those with suspicious personal history or histopathologic features were screened with MSI/IHC, June 2009-June 2011. Criteria were later (July 2011-July 2012) expanded to patients diagnosed <60 years, or at any age with suspicious features, and finally (after August 2012) universal screening was implemented. Screening techniques began with both MSI and IHC for every tumor, and later converted to IHC for two proteins, and MLH1 promoter methylation analysis when indicated. A genetic counselor contacted patients directly to offer genetic counseling appointments.

Two hundred and forty-five endometrial cancers (average age, 57 years) were screened. Sixty-two patients (25%) had abnormal results, and 42 patients were referred for genetic counseling. Of the 42 patients, 34 underwent genetic counseling, 28 pursued genetic testing, and 11 were diagnosed with LS. When age and pathology criteria were used, 27 eligible cases were overlooked for screening and 3 cases of LS were found only because a clinician requested screening.

Universal screening of endometrial cancers for LS is practical and successfully implemented with collaboration among genetic counselors, gynecologic oncologists, and pathologists.