Adjuvant hormone therapy in early-stage estrogen-positive breast cancer: a systematic review and network meta-analysis

Abstract

Relevance. Adjuvant hormonal therapy in postmenopausal women at an early-stage of estrogen-positive breast cancer (BC) includes anastrozole, letrozole, tamoxifen, toremifene, and exemestane, but the most effective drug is not known, and in this situation, the role of adjuvant hormonal therapy becomes especially debatable.The purpose of the study. Conducting an indirect comparison of oestrogen antagonists and aromatase inhibitors used in postmenopausal women with early-stage estrogen-positive breast cancer through a systematic search and selection of transitive data from randomized controlled trials (RCTs), and their subsequent quantitative synthesis in a network meta-analysis.Methods. We conducted a systematic review in two databases: MEDLINE and The Cochrane Central Register of Controlled Trials. Full-text versions of articles from RCTs were reviewed to evaluate the comparative efficacy of adjuvant hormonal monotherapy with toremifene, tamoxifen, anastrozole, letrozole, and exemestane in women with early-stage estrogen-positive postmenopausal breast cancer who had not previously received hormone therapy. Efficacy was assessed by overall survival (OS). A network meta-analysis was carried out using the NetMetaXL programme.Results. As a result of a systematic search, we selected 8 RCTs involving 25167 patients. When performing a synthesis of the obtained data using a network meta-analysis, no statistically significant differences in 5-year OS were obtained between the comparators.Conclusions. There are no clinically significant differences in 5-year OS between the compared drugs of adjuvant hormonal monotherapy in early-stage breast cancer.