Real-world multi-country study of BRCA1/2 mutation testing among adult women with HER2-negative advanced breast cancer

Breast Cancer and Genetic BRCA1/2 Testing in Routine Clinical Practice: Why, When and For Whom?

Pathogenic variants of the tumor suppressor genes BRCA1 and BRCA2 are responsible for the majority of hereditary breast cancers; they are also becoming increasingly important to identify whether patients are suitable for targeted therapy with poly ADP-ribose polymerase inhibitors (PARPi). Patients with HER2-negative breast cancer and BRCA1/2 germline mutations can benefit significantly from PARPi therapy, and the findings of the OlympiAD and the EMBRACA phase III clinical trials for regulatory approval were recently expanded by the addition of the most recent OlympiA data on the treatment of patients with early disease and a high risk of recurrence. This means that BRCA1/2 germline testing to plan patient therapy is now also relevant for patients with early breast cancer and therefore has a direct impact on survival. Healthcare research data shows, however, that BRCA1/2 testing rates are strongly affected by familial history, cancer subtype (particularly triple-negative subtypes), and patient age at onset of disease (especially with regards to younger patients with breast cancer), despite the existing clear recommendations for BRCA1/2 germline testing to identify whether PARPi therapy is indicated. This article presents the clinical implications of identifying BRCA1/2 germline mutations in patients with breast cancer, the current recommendations on molecular diagnostics, and their implementation in practice. The treatment of patients with breast cancer has progressed greatly in recent years and now offers individual treatment concepts which can only be implemented after the targeted identification of individual parameters. As detection of a BRCA1/2 germline mutation is essential for planning individual therapy, where indicated, testing should be arranged as early as possible. It is the only way of identifying patients suitable for PARPi therapy and ensuring they receive the best possible treatment. This also applies to patients with a negative familial history, HR-positive disease, or who are older at onset of disease.

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

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.