Abstract
Physical activity is recommended for the management of cancer-related fatigue (CRF), yet the evidence is primarily based on interventions delivered during cancer treatment, with no eligibility criterion for fatigue. There is a need to examine the quantity and quality of the existing literature on physical activity for clinically-relevant CRF that continues after cancer treatment (post-cancer fatigue). The objective of this systematic review was to summarize and evaluate the effect of physical activity on post-cancer fatigue in adults, using randomized trials where fatigue was an eligibility criterion. Studies were included if they: included adult participants with a cancer diagnosis who had completed initial cancer treatments (e.g., surgery, chemotherapy and/or radiation therapy); explicitly stated that fatigue was a participant eligibility/inclusion criterion, regardless of how this was described or assessed; involved a physical activity intervention; measured fatigue as a primary or secondary outcome. A previous systematic search was updated and electronic databases (Ovid MEDLINE(R), Ovid MEDLINE(R) and In-Process & Other Non-Indexed Citations, Embase, PsycINFO, Cochrane Database of Systematic Reviews, and CINAHL) were last searched on October 13, 2020. The risk of bias was assessed using the Cochrane Collaboration’s tool for randomized trials. A random-effects meta-analysis for the severity of fatigue across different scales at the end of the intervention was conducted. A total of 1035 participants were randomized across 19 studies. We estimate that less than 10% of the randomized trials of physical activity for CRF include people with post-cancer fatigue. The effect of physical activity on post-cancer fatigue was modest and variable (Hedge’s g -0.40; p = 0.010; 95% prediction intervals -1.41 to 0.62). Most studies had an unknown or high risk of bias, there was substantial heterogeneity between trials and evidence for the effect of physical activity on post-cancer fatigue was graded as low certainty. Including people with clinically relevant fatigue is a priority for future research in cancer survivorship. Additional transparently reported randomized clinical trials are needed to better understand the benefits of physical activity for post-cancer fatigue.