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 People with Metastatic Breast Cancer (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 to 0.5), moderate (0.5 to 0.8) and large (>0.8) describe the size of the effect. Risk of bias (ROB) 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. Systematic Review Registration Number: PROSPERO CRD42022304528. Contribution of the 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.