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 (Δ=1.009, CI 0.222-1.797) showed a significantly greater effect than a combination of aerobic and resistance exercises (Δ=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.