Impact of clinicopathological characteristics on the efficacy of neoadjuvant therapy in patients with human epidermal growth factor receptor-2-positive breast cancer.

Neoadjuvant therapy has become increasingly common in human epidermal growth factor receptor-2 (HER2)-positive breast cancer. In this study, we examined the impact of different clinicopathological characteristics on pathological complete response (pCR) in patients treated with anti-HER2 agents. The PubMed and Embase databases were searched from inception through April 2017 to identify studies that met pre-specified criteria. The odds ratios (ORs) and 95% confidence intervals (CIs) were extracted directly or were calculated with other available information. Eleven randomized controlled trials (RCTs) that involved 3,269 HER2-positive women were included in this meta-analysis. Patients with hormone receptor (HR)-negative breast cancer benefited more from anti-HER2 therapy than did patients with HR-positive tumours (OR, 2.25; 95% CI, 1.93-2.62). Furthermore, this improvement in pCR was independent of anti-HER2 agents, phase, combined chemotherapy, neoadjuvant duration, year the trials started and region where the trials were conducted. Patients with small tumours achieved greater benefits than patients with large tumours (OR, 1.25; 95% CI, 1.00-1.55). Age did not predict an additional benefit from anti-HER2 neoadjuvant treatment (OR, 1.02; 95% CI, 0.73-1.45). The impact of nodal status on pCR was dependent on the anti-HER2 agents. In conclusion, for HER2-targeted neoadjuvant treatment in breast cancer, greater benefits were achieved in patients with small HR-negative tumours compared with patients with large HR-positive tumours. These results may improve drug development and treatment strategies, economic analyses and the design and interpretation of clinical trials.