Impact of BRCA Mutation on Treatment Outcomes of Endocrine Therapy ± CDK4/6 Inhibitors in Hormone Receptor–Positive/Human Epidermal Growth Factor Receptor-2–Negative Breast Cancer: A Systematic Review and Meta-Analysis

PURPOSE: alteration (Alt) in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor-2-negative (HER2-) breast cancer (BC) treated with endocrine therapy (ET) ± cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) remains unresolved. This meta-analysis aimed to define their influence on therapy outcomes in the early and metastatic stages. MATERIALS AND METHODS: status. A separate analysis of individual-patient data for metastatic HR+/HER2- BC extracted from MSK-MET project was performed. RESULTS: carriers. CONCLUSION: HR+/HER2- BC.