Initial Results of Multigene Panel Testing for Hereditary Breast and Ovarian Cancer and Lynch Syndrome.

Multigene panel testing for hereditary cancer risk has recently become commercially available; however, the impact of its use on patient care is undefined. We sought to evaluate results from implementation of panel testing in a multidisciplinary cancer center. We performed a retrospective review of consecutive patients undergoing genetic testing after initiating use of multigene panel testing at Loma Linda University Medical Center. From February 13 to August 25, 2014, 92 patients were referred for genetic testing based on National Comprehensive Cancer Network guidelines. Testing was completed in 90 patients. Overall, nine (10%) pathogenic mutations were identified: five BRCA1/2, and four in non-BRCA loci. Single-site testing identified one BRCA1 and one BRCA2 mutation. The remaining mutations were identified by use of panel testing for hereditary breast and ovarian cancer. There were 40 variants of uncertain significance identified in 34 patients. The use of panel testing more than doubled the identification rate of clinically significant pathogenic mutations that would have been missed with BRCA testing alone. The large number of variants of uncertain significance identified will require long-term follow-up for potential reclassification. Multigene panel testing provides additional information that may improve patient outcomes.