Magnitude of trastuzumab benefit in patients with HER2-positive, invasive lobular breast carcinoma: Results from the HERA trial

Abstract

Purpose To evaluate the benefit of adjuvant trastuzumab in patients diagnosed with human epidermal growth factor receptor 2 (HER2) -positive invasive lobular carcinoma (ILC) enrolled onto the Herceptin Adjuvant (HERA) trial. Patients and Methods Patients randomly assigned to receive one year of trastuzumab and one year of observation in the HERA trial were included (n - 3,401). Centrally reviewed estrogen receptor (ER), progesterone receptor (PgR), and HER2 copy numbers were used. First site-specific relapse pattern was evaluated for ILC and invasive ductal carcinoma (IDC). The magnitude of trastuzumab benefit was assessed using the Cox proportional hazards model for disease-free survival (D..