Fehrenbacher L, Cecchini RS, Geyer CE, et al. - Whether an improved invasive disease-free survival (IDFS) could be achieved by adding trastuzumab to adjuvant chemotherapy (CRx) in the treatment of patients with HER2-negative breast cancer, was inquired in the NSABP B-47 trial. Participants included 3,270 women with high-risk primary invasive breast cancer (IBC). Using randomization, researchers assigned the participants to CRx with or without 1 year of trastuzumab. CRx included either docetaxel plus cyclophosphamide or doxorubicin and cyclophosphamide followed by weekly paclitaxel for 12 weeks. Participants were observed for a median duration of 46 months. Findings revealed that no improvement in IDFS, distant recurrence-free interval, or overall survival, was brought about by trastuzumab added to CRx in the treatment of women with non-HER2–overexpressing IBC. Furthermore, no benefit was afforded by trastuzumab in women without IHC (immunohistochemistry) 3+ or FISH (fluorescence in situ hybridization) ratio-amplified breast cancer.