Routine universal screening for Lynch syndrome in colorectal cancer patients in the community setting.
1512 Background: Identification of colorectal cancer (CRC) cases that are due to Lynch Syndrome (LS) is important to prevent secondary malignancies or development of additional malignancies among relatives. Utilization of clinical criteria to select CRC patients for laboratory testing fails to identify a significant proportion of patients whose CRC is due to LS. Therefore, universal screening for LS among CRC patients has been advocated by the Evaluation of Genomic Applications in Practice and Prevention Working Group. However, the feasibility of routine universal screening has not been evaluated in a community-based, non-research setting. We implemented a universal screening protocol for LS as part of routine care of CRC at Norton Healthcare, a multi-institutional community-based healthcare organization. Methods: Beginning in October 2009, all resected CRC tumors automatically underwent immunohistochemistry analysis (IHC) for Lynch Syndrome-associated mismatch repair gene (MMR) expression. Selected patients who underexpressed MLH1 also underwent testing for the BRAF V600E mutation. Patients who had a BRAF V600E mutation were considered to have sporadic CRC. All other patients with abnormal IHC were automatically referred for genetic counseling. We retrospectively reviewed the outcomes of genetic counseling in all patients referred through this universal screening protocol. Results: Between October 2009 and December 2011, 388 patients underwent resection of CRC, all of whom had IHC for MMR expression. Seventy patients were identified as having abnormal IHC. Sixty-two had MLH1/PMS2 underexpression, of which 18 underwent BRAF testing and 13 had a BRAF V600E mutation. Eight had MSH2/MSH6 underexpression. Nine patients have been confirmed to have LS, 31 have been found not to have LS, and 19 are in the process of evaluation. Seven patients declined genetic counseling, and 4 died before they could be adequately evaluated. Conclusions: Universal screening for CRC due to LS, using IHC with select BRAF V600E mutation testing and automated referral for genetic counseling, is feasible in the community setting. Funded in part with federal funds: NCI, NIH, Contract No. HHSN261200800001.