Factors influencing oncologists’ decisions for germline BRCA testing and adjuvant therapy selection in HER2-negative early breast cancer

Introduction With advances in targeted early breast cancer (eBC) treatment, research is needed to understand the factors influencing biomarker testing and respective treatment selection among physicians in routine clinical practice. The purpose of this study was to evaluate factors influencing oncologist decisions for germline BReast Cancer gene (BRCA) mutation (gBRCAm) testing and adjuvant therapy in human epidermal growth factor receptor 2-negative (HER2-) early breast cancer (eBC). Materials and methods US oncologists completed an online survey from April to July 2024, which included preference exercises to evaluate the relative importance of select factors for gBRCA testing and adjuvant treatment selection in gBRCAm HER2- eBC. Results Among 150 surveyed oncologists, age was over twice as influential as tumor size and lymph node involvement in gBRCA testing decisions for hormone receptor-positive (HR+)/HER2- eBC. Nearly one-quarter reported that gBRCA test results did not impact their treatment decisions. Olaparib-based regimens were the preferred adjuvant treatment for gBRCAm HER2- eBC, over Cyclin-Dependent Kinases 4 and 6 inhibitors alone for HR+/HER2- eBC, immunotherapy or capecitabine alone for triple-negative eBC, and no treatment. Efficacy was the most important treatment attribute. Oncologists reported that patient unwillingness to undergo gBRCA testing or receive adjuvant olaparib due to cost, treatment duration, or other reasons were barriers to treatment. Conclusions Despite guideline recommendations, age drives oncologists’ gBRCA testing decisions. To support the preference for olaparib-based adjuvant treatment in gBRCAm HER2- eBC, increased physician awareness of guidelines and the rationale for gBRCAm testing is needed to improve identification of eligible patients.