Effectiveness of Neoadjuvant Chemotherapy in Breast Cancer Patients: A Systematic Review and Multivariate Meta-analysis

Background The oncological outcomes are generally correlated e.g., Overall Survival (OS) and Disease Free Survival (DFS). Multivariate meta-regression, a relatively new technique used for multiple correlated outcomes, takes into consideration the hierarchal framework of within study as well as between study correlations among outcomes. This study deals with such analytical results under a systematic review of Randomized Controlled trials (RCTs) assessing effectiveness of Neoadjuvant Chemotherapy (NACT) with Adjuvant Chemotherapy (ACT) in breast cancer patients in terms of oncological outcomes. Materials and methods Final search of PubMed and Cochrane databases conducted on January 21, 2016 revealed 1239 records. Seventeen eligible studies could finally be identified after full text review of 61 screened records. Risk of Bias was assessed by Cochrane Risk of Bias tool. Unknown within study correlations were estimated by Riley’s method. The sub-group analysis, sensitivity analysis and meta-regression on the basis of study level characteristics were performed. Since outcomes under consideration are correlated, multivariate meta-regression was used to synthesize the results. Results are reported as Hazard Ratio & 95%CI. Results The heterogeneity, I 2 statistics, ranged from 0% to 54% for the considered outcomes. The effectiveness of NACT was not found statistically significant regarding death, Recurrence and Distant Meta-stasis. Conclusions Multivariate meta-analysis refines the results from univariate meta-analysis with gain in precision especially for outcomes with higher heterogeneity