Neoadjuvant chemotherapy and concomitant trastuzumab in breast cancer: a pooled analysis of two randomized trials

The aim of this meta analysis was to evaluate the benefit of adding concomitant trastuzumab to neoadjuvant(anthracycline and taxane-based) chemotherapy, which was assessed based on two published randomized controlled trials. The eligible patients were randomized to receive either neoadjuvant chemotherapy alone or with concurrent administration of trastuzumab. Relative risks(RRs) with 95% confidence intervals of pathologically complete response in breast and nodes, relapse-free survival, overall survival, and cardiotoxicity were calculated.The RR of obtaining a pathologically complete response in breast and nodes was 2.07 in the experimental arms(1.41–3.03; P = 0.0002; P for heterogeneity 0.63; fixed effect model). The RR of being disease free was 0.67 in favor of the experimental arms (0.48–0.94; P = 0.02; P for heterogeneity 0.22; fixed affect model). The RR of being alive was 0.67 in favor of the experimental arms (0.39–1.15;P= 0.15). The RR of a cardiac event was 1.09 in the arms treated with chemotherapy and concomitant trastuzumab, but that is not significant (0.6–1.98; P =0.77). The addition of concomitant trastuzumab to neoadjuvant chemotherapy doubles the risk of obtaining a pathologically complete response in both breast and nodes compared with controls. Trastuzumab significantly reduces the risk of relapse and does not increase the risk of cardiotoxicity,despite being associated with anthracyclines. The largest benefit was observed in a locally advanced patient study.