ERBB2 and breast cancer: Furthermore, a joint analysis of two large clinical trials (NCCTG N9831 and NSABP B-31) found that patients with early-stage HER2-positive breast cancer benefited from the addition of trastuzumab to conventional chemotherapy followed by treatment with paclitaxel, resulting in a significant and sustained reduction in cancer recurrence rates and a 37% improvement in overall survival (18).