Efficacy of exercise interventions in modulating cancer-related fatigue among adult cancer survivors: a meta-analysis.

BACKGROUND The purpose of this meta-analysis was to explore the efficacy of exercise as a nonpharmacologic intervention to reduce cancer-related fatigue (CRF) among adult cancer survivors. We also investigated how different components of the exercise prescription (Ex R(x)), methodologic considerations, and subject characteristics modulate CRF. METHODS A systematic search for randomized controlled trials was conducted using words related to cancer, exercise, and fatigue. RESULTS In total, 44 studies with 48 interventions qualified, including 3,254 participants of varying cancer types, stages of diagnosis, treatments, and exercise interventions. Cancer survivors in exercise interventions reduced their CRF levels to a greater extent than usual care controls, d(+) = 0.31 (95% CI = 0.22-0.40), an effect that appeared to generalize across several types of cancer. CRF levels improved in direct proportion to the intensity of resistance exercise (β = 0.60, P = 0.01), a pattern that was stronger in higher quality studies (β = 0.23, P < 0.05). CRF levels also reduced to a greater extent when interventions were theoretically driven (β = 0.48, P < 0.001) or cancer survivors were older (β = 0.24, P = 0.04). CONCLUSIONS Exercise reduced CRF especially in programs that involved moderate-intensity, resistance exercise among older cancer survivors and that were guided by theory. IMPACT Our results indicate exercise interventions for adult cancer survivors should be multi-dimensional and individualized according to health outcome and cancer type.