Effects of exercise interventions on cancer-related fatigue and quality of life in patients with metastatic breast cancer: a systematic review and meta-analysis

Objective To systematically evaluate the effects of exercise interventions on cancer-related fatigue (CRF) and quality of life (QoL) in patients with metastatic breast cancer (MBC), and to further examine their effects on specific fatigue dimensions and QoL-related functional domains, as well as the potential influence of intervention duration on the primary outcomes. Methods We systematically searched seven electronic databases, including CNKI, Wanfang Data, PubMed, Scopus, CINAHL, the Cochrane Library, and Web of Science, covering the period from 2000 to September 2026. Eligible studies were randomized controlled trials (RCTs) that investigated exercise interventions for cancer-related fatigue and quality of life in patients with MBC. Statistical pooling was performed with Review Manager 5.4, and Stata was used for sensitivity analysis and assessment of publication bias. Results Eleven RCTs were included, with 656 participants contributing to the CRF analysis. Exercise interventions significantly reduced CRF in patients with MBC [SMD = 0.44, 95% CI (0.15, 0.74), p = 0.003; I² = 60%]. Eight studies involving 517 participants reported overall QoL, and the pooled analysis showed a significant improvement with exercise [SMD = 0.29, 95% CI (0.12, 0.47), p = 0.001; I² = 0%]. For CRF-related secondary outcomes, significant reductions were observed in emotional fatigue [SMD = −0.47, 95% CI (−0.68, −0.26), p < 0.00001], fatigue interference [SMD = −0.87, 95% CI (−1.35, −0.40), p = 0.0003], and physical fatigue [SMD = −0.84, 95% CI (−1.05, −0.63), p < 0.00001]. For QoL-related secondary outcomes, exercise significantly improved physical functioning [SMD = 0.67, 95% CI (0.38, 0.97), p < 0.00001] and emotional functioning [SMD = 0.27, 95% CI (0.10, 0.45), p = 0.002]. Conclusion Exercise interventions significantly improve cancer-related fatigue and quality of life in patients with metastatic breast cancer and may serve as an effective supportive-care strategy. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420261472843 , identifier CRD420261472843.