Neoadjuvant dose-dense chemotherapy for locally advanced breast cancer: a meta-analysis of published studies

Large operable or locally advanced breast cancers (BCs) are usually treated with neoadjuvant chemotherapy (CT) before surgery. However, there is no evidence to support an improvement in efficacy with dose-dense (DD) CT in this setting. We, therefore, carried out a meta-analysis to investigate whether DD-CT was more effective than the reference (every 3 weeks anthracyclines±taxanes) standard-dose CT as neoadjuvant treatment for BC. We searched Pubmed, SCOPUS, EMBASE, the Web of Science, CINAHL, and the Cochrane Central Register of Controlled Trials for randomized trials comparing conventional versus DD neoadjuvant CT for BC. Odds ratios (ORs) for pathologic complete responses (ypT0N0M0: pCR) and hazard ratios (HRs) of death and recurrence [overall survival (OS), and disease-free survival (DFS)] were estimated and pooled. A QUADAS-2 report for all studies included in the final analysis was tabulated for the risk of bias and applicability. A total of six randomized trials fulfilled the inclusion criteria. The pooled rates of the pCR were 13.5 and 9.2% in the experimental and control arms. A significant increase in the pCR [OR=1.55, 95% confidence interval (CI) 1.18-2.02, P=0.001] was noted with neoadjuvant DD-CT. However, the patients who received DD-CT did not have significantly better DFS and OS rates (DFS: HR=0.88, 95% CI 0.76-1.01, P=0.06; OS: HR=0.89, 95% CI 0.78-1.02, P=0.08). Even with the limitation of a relatively short follow-up period, this meta-analysis shows that DD neoadjuvant CT, despite not leading to a significant increase in survival, increases by 46.7% the possibility of achieving a pCR in operable and locally advanced BC. This treatment should thus be considered one of the backbone treatments of choice when neoadjuvant therapy is planned.