Genetics-Supported Mainstream Testing Improves Access and Efficiency for Patients With Breast Cancer

BACKGROUND: The demand for germline genetic testing in oncology is outpacing traditional genetics service capacity. Mainstream genetic testing, where oncologists initiate testing with structured support, may expand access while maintaining quality. PATIENTS AND METHODS: We performed a retrospective chart review of patients with breast cancer who underwent germline genetic testing at Massachusetts General Hospital from March 2021 to July 2022. Patients were managed via either a traditional model (genetics professional-led) or a genetics supported mainstream model (oncologist-led, with genetic counseling assistant support). Outcomes included test volume, turnaround times, documentation of consent and results disclosure, and follow-up for pathogenic variant (PV) carriers. RESULTS: Among 805 patients (traditional: n=305; mainstream: n=500), the mainstream model significantly shortened the interval from diagnosis to consent (22.4 vs 59.5 days; P<.0001) and from consent to final report (28.2 vs 35.2 days; P=.039). Documentation of informed consent was >99% in both models. However, documentation of final result disclosure was significantly lower in the mainstream model (82.4% vs 100%; P<.0001). All PV carriers were successfully referred to genetic counseling. The mainstream model substantially increased test volume without compromising compliance or follow-up care. CONCLUSIONS: A structured mainstream genetic testing model, supported by trained assistants and robust workflows, improves access and test turnaround time for patients with breast cancer while maintaining quality standards, including documentation of consent and test ordering. This study did not evaluate whether surgical decisions were affected; however, timely results may support care planning in select cases. Continued efforts are needed to improve documentation of result disclosure by ordering providers.