The effects of a prescribed exercise programme in people with metastatic breast cancer: a systematic review

Objective To synthesise available evidence on the effects of a prescribed exercise programme in PwMBC. Data sources Medline, Embase, CINAHL, Web of Science and Scopus were searched up to January 2024. Study selection Randomised controlled trials (RCTs) recruiting PwMBC to an exercise intervention were included. The primary outcome was Quality of Life (QOL). Secondary outcomes included physical performance, muscle health, cancer-related fatigue (CRF) and physical activity (PA). Study appraisal and synthesis methods Meta-analysis was not possible due to the low number of included studies. We calculated the effect size (ES), with 95% confidence intervals (95% CIs) of individual studies, adjusting for small sample size. Cohen's criteria for small (0.2-0.5), moderate (0.5-0.8) and large (>0.8) describe the size of the effect. Risk of bias was assessed using the Cochrane ROB version 1 tool. Results Three RCTs (n=149 PwMBC) were included. Results showed no significant between-group effects in the primary outcome, QOL. Whilst effects in favour of prescribed exercise were observed in CRF (ES 1.3, 95% CI 0.06 to 2.35) and PA (ES 0.83, 95% CI 0.14 to 1.42) in two separate studies, as the lower bound of the 95% CI did not reach Cohen's threshold, there is considerable uncertainty regarding the treatment effect. Conclusions There is currently insufficient evidence to support the use of prescribed exercise to improve QOL, physical performance, muscle health, CRF and PA in PwMBC. Further high-quality trials are required to investigate the effectiveness of exercise interventions in PwMBC. Review registration Prospective registration in the PROSPERO register of Systematic Reviews (CRD42022304528). Contribution of Paper •Despite guidelines and recommendations on the positive role of exercise, the evidence for prescribed exercise programmes for PwMBC is limited. •This systematic review of three trials found insufficient evidence to support the use of prescribed exercise to improve QOL, physical performance, muscle health, CRF and PA in PwMBC. •Further high-quality, adequately powered trials are required to investigate the effectiveness of exercise interventions on QOL, CRF, PA, physical performance and muscle health in PwMBC.