BRCA1/2 Mutation Testing in Patients with HER2-Negative Advanced Breast Cancer: Real-World Data from the United States, Europe, and Israel.

Abstract

Poly(adenosine diphosphate-ribose) polymerase inhibitors are approved to treat patients harboring a germline breast cancer susceptibility gene 1 or 2 mutation (BRCA1/2mut) with human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). This study evaluated differences in patient demographics, clinical characteristics, and BRCA1/2mut testing within the United States (US), European Union 4 (EU4; France, Germany, Italy, and Spain), and Israel in a real-world population of patients with HER2- ABC. Oncologists provided chart data from eligible patients from October 2019 through March 2020. In the US, EU4, and Israel, 73%, 42%, and 99% of patients were tested for BRCA1/2mut, respectively. In the US and the EU4, patients who were not tested versus tested for BRCA1/2mut were more likely to have hormone receptor-positive (HR+)/HER2- ABC (US, 94% vs. 74%, p < 0.001; EU4, 96% vs. 78%, p < 0.001), less likely to have a known family history of BRCA1/2-related cancer (US, 6% vs. 19%, p = 0.002; EU4, 10% vs. 28%, p < 0.001), and were older (US, 68.9 vs. 62.5 years, p < 0.001; EU4, 66.7 vs. 58.0 years, p < 0.001). Among tested patients, genetic counseling was received by 45%, 53%, and 98% with triple-negative breast cancer, and 36%, 36%, and 98% with HR+/HER2- ABC in the US, EU4, and Israel, respectively. Efforts should be made to improve BRCA1/2 testing rates in the US and Europe.