ERBB2 and breast cancer: Both durations of trastuzumab were effective among women with HER2+ early-stage breast cancer, but 12 months of trastuzumab appeared to have better DFS [hazard ratio (HR) = 1.10, 95% confidence interval (CI): 0.99-1.23, <i>P</i> = 0.09] and better OS than 6 months of trastuzumab (HR = 1.14, 95% CI: 0.99-1.32, <i>P</i> = 0.07).