Optimising exercise prescription for cancer-related fatigue, lean mass, physical function and muscle strength in women with breast cancer: a systematic review with dose–response network meta-analysis

OBJECTIVE: To systematically review and investigate the dose-response (DR) relationship of aerobic exercise (AE), resistance exercise (RE) and combined (COMB) exercise programmes on cancer-related fatigue, lean mass, physical function and muscle strength in women with breast cancer during and following primary treatment. DESIGN: Systematic review with DR network meta-analysis (DR-NMA; CRD42023491118). DATA SOURCES: CINAHL, Embase, LILACS, PubMed, SciELO, SPORTDiscus and Web of Science were searched from inception to 10 January 2024, with an updated search in April 2025. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomised controlled trials evaluating COMB, RE or AE in women with breast cancer on the four specified outcomes. RESULTS: 64 trials (n=5156) were included. COMB was the most effective modality for improving fatigue and lean mass, and RE was the most effective for improving physical function and muscle strength. The smallest effective doses of COMB associated with significant changes in fatigue (standardised mean differences (SMD) 0.23 (95% CI 0.18 to 0.28)) and lean mass (SMD 0.30 (95% CI 0.22 to 0.38)) were 18 and 11 metabolic equivalents per week (METs.min/week), respectively. For RE, about 7-8 METs.min/week produced significant improvements in physical function (SMD 0.23 (95% CI 0.15 to 0.30)) and strength (SMD 0.24 (95% CI 0.20 to 0.29)). Fatigue benefits (SMD 0.58 (95% CI 0.46 to 0.69)) plateaued at ~1428 METs.min/week for COMB, whereas no plateau was observed for lean mass or strength across the evaluated dose range, with effects increasing throughout the available dose range. CONCLUSIONS: COMB and RE were the most effective interventions across outcomes in women with breast cancer. Benefits for the outcomes assessed in this systematic review with DR-NMA were achieved with exercise doses as low as 10-40 min/week. PROSPERO REGISTRATION NUMBER: CRD42023491118.