The effect of exercise on cancer-related fatigue in cancer survivors: a systematic review and meta-analysis

Objective: The objective of the study was to conduct systematic review and meta-analysis to establish the effect of exercise interventions on cancer-related fatigue (CRF) in cancer survivors, compared to non-exercise intervention controls. Methods: Trials published between January 1st 2000 and August 17th 2016 were included through PubMed database : search and search of references. Eligible trials compared the effect of an exercise intervention on CRF compared to non-exercise intervention controls, with CRF as primary outcome and measured by validated self-report questionnaire, in cancer survivors not receiving palliative care. We evaluated risk of bias of individual trials following Cochrane Quality criteria. We performed a random-effects meta-analysis in the low risk of bias trials with intervention type, exercise intensity, adherence, and cancer type as moderators, and also performed meta-regression analyses and a sensitivity analysis including the high risk of bias trials. Results: Out of 274 trials, 11 met the inclusion criteria, of which six had low risk of bias. Exercise improved CRF with large effect size (Cohen's d 0.605, 95% CI 0.235-0.975) with no significant difference between types of cancer. Aerobic exercise (Delta= 1.009, CI 0.222-1.797) showed a significantly greater effect than a combination of aerobic and resistance exercises (Delta= 0.341, CI 0.129-0.552). Moderator and meta-regression analyses showed high adherence yielding best improvements. Conclusion: Exercise has a large effect on CRF in cancer survivors. Aerobic interventions with high adherence have the best result.