The effect of physical activity on fatigue among survivors of colorectal cancer: a systematic review and meta-analysis

PURPOSE: Favorable health outcomes among cancer survivors are increasingly being attributed to lifestyle factors like physical activity, which is now promoted in clinical guidelines. However, the available evidence indicates that physical activity may also reduce fatigue in this patient group. In this systematic review, we aimed to examine whether physical activity could reduce fatigue among survivors of colorectal cancer. METHODS: The databases of Medline, CINAHL, and PsycINFO were systematically searched, using combinations of MeSH and free-text terms for colorectal cancer, physical activity, and fatigue. Randomized controlled trials and cohort studies with longitudinal data collection were included. We performed a random-effect meta-analysis. RESULTS: Seven studies were included, five were randomized controlled trials, and two were cohort studies. A meta-analysis of the randomized controlled trials, which comprised 630 survivors in total, failed to show that physical activity had a significant effect on fatigue (standardized mean difference = 0.21 (− 0.07 to 0.49)); however, reduced levels of fatigue were observed in all studies. The results for the cohort studies were inconclusive: one showed that increasing levels of physical activity were significantly associated with decreasing levels of fatigue; the other showed that decreasing levels of fatigue were not associated with increasing levels of physical activity. CONCLUSIONS: Based on the data reviewed, we cannot draw definitive conclusions about the effects of physical activity on fatigue. None of the included studies were performed among fatigued survivors of colorectal cancer. More research is needed in this population, ensuring that the trials are appropriately powered to find differences in fatigue.