Sequential versus concurrent adjuvant chemo-endocrine therapy for HR+ early breast cancer: a systematic review and Bayesian network meta-analysis

Background Chemo-endocrine therapy is the standard adjuvant treatment strategy for hormone receptor-positive (HR+) early breast cancer. Our research aimed to compare the efficacy of adjuvant chemo-endocrine therapies, regarding different endocrinal regimens and integration sequences (sequential or concomitant), for HR+ early breast cancer. Methods PubMed, Embase, the Cochrane Library and web of science were searched for articles published before October 2018 with Clinicaltrials.gov (https://clinicaltrials.gov) for registered clinical trials and ASCO, AACR, ESCO, SABCS meeting abstracts for addition. Randomized clinical trials (RCTs) comparing chemotherapy and/or endocrine therapy in the adjuvant treatment of primary breast cancer patients were included. Hazard ratios (HRs) of disease-free survival (DFS) and overall survival (OS) were extracted and analyzed in Bayesian analysis. Patients were stratified by menopause status. Results Thirty-three trials with 28,515 patients and 19 treatments were enrolled. Comparisons between regimens has seen better efficacy of ovarian function suppressor (OFS) + aromatase inhibitors (AI) than OFS + tamoxifen, either used concurrently [HR =0.69, 95% credible intervals (CrI): 0.47–1.02] or sequentially with chemotherapy (HR =0.72, 95% CrI: 0.49–1.06) in premenopausal patients. Adding OFS to tamoxifen was marginally better than tamoxifen used alone (DFS: HR =0.85, 95% CrI: 0.65–1.09; OS: HR =0.77, 95% CrI: 0.52–1.08). Comparisons between different sequences of chemo-endocrine therapy proved equal efficacy in premenopausal and postmenopausal patients. Recommendation was given based on ranking of treatments. Sequential and concurrent use of chemotherapy and OFS + AI ranked equally in premenopausal patients and were recommended as the best option. However, tamoxifen ranked higher when used concurrently with chemotherapy in both premenopausal and postmenopausal HR+ early breast cancer. Conclusions In the adjuvant chemo-endocrine therapy for premenopausal HR+ early breast cancer, concurrent and sequential adjuvant chemo-endocrine therapy was demonstrated of equal efficacy in both postmenopausal and premenopausal HR+ early breast cancer. Trial Registration PROSPERO CRD42018104889.