Germline BRCA-Mutated HER2-Negative Advanced Breast Cancer: Overcoming Challenges in Genetic Testing and Clinical Considerations When Using Talazoparib.

Genetic testing is essential to the diagnosis and management of patients with breast cancer. For example, women who carry mutations in BRCA1/2 genes have an increased lifetime risk of breast cancer and the presence of these mutations may sensitize the patient to treatment with poly(ADP-ribose) polymerase (PARP) inhibitors. Two PARP inhibitors are approved by the US Food and Drug Administration for patients with germline BRCA-mutated advanced breast cancer (olaparib and talazoparib). The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer (Version 2.2023) recommend that all patients with recurrent or metastatic breast cancer (mBC) be assessed for the presence of germline BRCA1/2 mutations. However, many women eligible for genetic testing do not receive it. Here, we provide our perspectives on both the importance of genetic testing and the challenges patients and community clinicians may face when trying to access genetic testing. We also present a hypothetical case study involving a female patient with germline BRCA-mutated human epidermal growth factor receptor 2 (HER2)-negative mBC to highlight potential clinical considerations on the use of talazoparib, including the decision to initiate therapy, dosing considerations, potential drug-drug interactions, and managing side effects. This case illustrates the benefits of a multidisciplinary approach to managing patients with mBC and involving the patient in the decision-making process. This patient case is fictional and does not represent events or a response from an actual patient; this fictional case is for educational purposes only.