Addition of endocrine therapy to dual anti-HER2 targeted therapy in initial treatment of HER2 + /HR + metastatic breast cancer

According to a real-life data analysis of patients with HER2+/HR+ metastatic breast cancer who had received chemotherapy plus trastuzumab/pertuzumab, those who also received endocrine therapy had a significantly improved 5-year PFS (HR 0.58, CI 0.37-0.89; p = 0.014) and OS (HR 0.52, CI 0.31-0.90; p = 0.018), with no increase in adverse events, compared with those who did not receive ET.