Long-term (7-year) outcomes of universal mismatch repair screening (uMMR) of 1156 colorectal (CRC) and endometrial cancers (EC) in an academic setting.

1513Background: uMMR of CRC/EC for Lynch syndrome (LS) is recommended to identify the 2-3% of incident CRC/EC with germline MMR mutations in MLH1, MSH2, MSH6, and PMS2. Many US centers use a positive immunohistochemical (IHC+) tumor test to prompt further evaluation such as genetic counseling (GC). Efficacy of uMMR is established, but real-world performance is not. W/recent Blue Ribbon Panel recommendations for broad implementation, we reviewed uMMR effectiveness in an academic cancer center. Methods: Outcomes of all CRC/EC undergoing uMMR from 9/2011 (start of uMMR at Fox Chase Cancer Center) to 12/2017 were reviewed. uMMR results are reported in the surgical pathology report and by email to providers w/a PDF test report meant for pts. Results [IHC, MSI, BRAF, MLH1 promoter methylation, gene testing] and clinical data were extracted from a clinical genetics database and the EMR. Associations were tested by chi-square and T-test (2-sided). Results: From 1156 screened tumors, 278 (24.0%) had +IHC: 112 (40....