Genetic counselor approaches to BRCA1/2 direct-to-consumer genetic testing results

The National Comprehensive Cancer Network recommends clinical-grade genetic testing to confirm commercial results from direct-to-consumer genetic testing (DTC-GT) companies and third-party interpretation (TPI) services; however, the type of confirmatory testing that genetic counselors (GCs) recommend remains uncharacterized. Therefore, we aimed to describe GCs testing strategies for patients who have already obtained DTC-GT results (23andMe) or TPI data (Promethease) that reported a BRCA1/2 pathogenic variant. We invited GCs specializing in clinical cancer genetics to complete an online survey distributed to members of the National Society of Genetic Counselors. The survey, completed by 80 respondents, contained case scenarios featuring probands with variable personal and family histories of cancer. Our results show that the majority of participating GCs have counseled patients for their health-related commercial test results; 94% have encountered patient DTC-GT reports (3 per year), and 69% have encountered patient TPI data (2 per year). Most participating GCs would recommend confirmatory clinical-grade testing for probands with a positive 23andMe BRCA1/2 result (77/80, 96%). However, there was strong variability between the type of recommended testing. Approximately 20% recommended single-site analysis, 11%-14% recommended the three Ashkenazi Jewish BRCA1/2 founder mutations, 4% recommended BRCA1/2 testing, and 61%-64% recommended multi-gene panel testing. The most commonly recommended panels were split between a breast and gynecological cancer-focused panel and a broad pan-cancer panel. The majority of participants (98%-100%) would also recommend confirmatory testing for patients with positive TPI data for BRCA1/2. Similarly, results were mixed between those who recommended targeted, single-site analysis (10%-15%) compared to a multi-gene panel (72%-83%). These data show that while most GCs were uniform in their practice of recommending confirmatory testing, they are mixed in their approach to the specific type of testing they would select. These results may help inform counseling approaches and consensus for this expanding group of patients.