Comparative effectiveness of adjuvant chemotherapy in early stage breast cancer: A network meta-analysis

Background There are several regimens recommended by the National Comprehensive Cancer Network (NCCN) for HER2-negative operable breast cancer. To our knowledge, no trials have yet been performed comparing these regimens head to head. We performed a network meta-analysis comparing the efficacy of NCCN-recommended chemotherapy regimens. Methods We searched Medline, Embase, Web of Science, the Cochrane Central Register of Controlled Trials, and World Health Organization (WHO) International Clinical Trials Registry Platform from inception to February 2020. We included randomized clinical trials comparing adjuvant regimens in predominantly node-positive operable breast cancer patients. We compared (1) DDACT, (2) TCx4 cycles, (3) TAC, and (4) ACWKT. Common comparators were (5) AC, (6) ACT, and (7) ACD. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed. The Cochrane risk of bias tool assessed quality of the studies. Odds ratios (ORs) were calculated as measures of treatment effects with AC as reference. We used Bayesian hierarchical random-effects models with noninformative priors for mixed multiple treatment comparisons. Effectiveness was estimated by disease-free and overall survival using ORs. Sensitivity analyses were performed. Safety outcomes included febrile neutropenia. Results We identified 7 randomized controlled trials with 16,332 patients. TC (odds ratio [95% confidence interval], 0.71 [0.36-1.40]), TAC (0.77 [0.37-1.57]), ACWKT (0.68 [0.34-1.38]), and DDACT (0.72 [0.35-1.42]) were similar for overall survival. TC (0.64 [0.36-1.14]), TAC (0.67 [0.39-1.15]), ACWKT (0.63 [0.37-1.07]), and DDACT (0.59 [0.35-1.01]) had similar disease-free survival benefit. With regard to toxicity, TAC (2.67 [0.30-21.04]) had the highest odds of febrile neutropenia. Conclusion The current generation of regimens are similar in efficacy. Given the lower toxicity of TCx4 comparatively, it is an acceptable alternative for lower-risk early-stage HER2-negative breast cancers.