Moderate-intensity exercise reduces fatigue and improves mobility in cancer survivors: a systematic review and meta-regression.

Question: Is there a dose-response effect of exercise on inflammation, fatigue and activity in cancer survivors?
Design: Systematic review with meta-regression analysis of randomised trials.
Participants: Adults diagnosed with cancer, regardless of specific diagnosis or treatment.
Intervention: Exercise interventions including aerobic and/or resistance as a key component.
Outcome Measures: The primary outcome measures were markers of inflammation (including C-reactive protein and interleukins) and various measures of fatigue. The secondary outcomes were: measures of activity, as defined by the World Health Organization's International Classification of Functioning, Disability and Health, including activities of daily living and measures of functional mobility (eg, 6-minute walk test, timed sit-to-stand and stair-climb tests). Risk of bias was evaluated using the PEDro scale, and overall quality of evidence was assessed using the Grades of Research, Assessment, Development and Evaluation (GRADE) approach.
Results: Forty-two trials involving 3816 participants were included. There was very low-quality to moderate-quality evidence that exercise results in significant reductions in fatigue (SMD 0.32, 95% CI 0.13 to 0.52) and increased walking endurance (SMD 0.77, 95% CI 0.26 to 1.28). A significant negative association was found between aerobic exercise intensity and fatigue reduction. A peak effect was found for moderate-intensity aerobic exercise for improving walking endurance. No dose-response relationship was found between exercise and markers of inflammation or exercise duration and outcomes. Rates of adherence were typically high and few adverse events were reported.
Conclusions: Exercise is safe, reduces fatigue and increases endurance in cancer survivors. The results support the recommendation of prescribing moderate-intensity aerobic exercise to reduce fatigue and improve activity in people with cancer.
Review Registration: PROSPERO CRD42015019164.
(Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.)