Adjuvant ovarian suppression for premenopausal hormone receptor-positive breast cancer: A network meta-analysis

Background Ovarian function suppressor (OFS) plus either tamoxifen (TAM) or aromatase inhibitor (AI) could improve the survival outcome for premenopausal hormone receptor-positive (HR+) breast cancer. However, the optimal OFS-based regimen and medication duration remain uncertain. This article aims to systematically evaluate the OFS-based adjuvant endocrine therapy for premenopausal breast cancer. Methods We searched several public databases from January 1980 to November 2020. A random model was adopted in this meta-analysis. We used the hazard ratio (HR) with a 95% confidence interval (CI) for the statistical analysis of efficacy. The primary outcome measures included overall survival and disease-free survival. Results A total of 32 articles with 37,224 cases were included in this network meta-analysis. OFS+TAM improved 5-year disease-free survival (HR -0.09, 95% CI -0.16 to -0.01) and 5-year overall survival (HR -0.18, 95% CI -0.33 to -0.03) compared with TAM monotherapy. For OFS+AI, although the 5-year disease-free survival was improved (HR -0.18, 95% CI -0.29 to -0.08), the 5-year overall survival was not improved (HR -0.13, 95% CI -0.43 to 0.18). In subgroup analysis, both OFS+AI and OFS+TAM showed a protective effect in stage I-III patients compared with stage I-II patients. For the course of therapy, OFS+TAM for 2-years could achieve clinical benefit and the best course of therapy of OFS+AI still waits for further study. Conclusions OFS+TAM might be a better option than OFS+AI for premenopausal intensive adjuvant endocrine therapy. Stage III patients are more suitable for the OFS-based therapy. For the medication duration, the 2-years course of OFS+TAM could be effective. This analysis provides helpful information for selecting therapeutic regimen in intensive adjuvant endocrine therapy and identifying the target population.