The Effect of Exercise on Pain in People with Cancer: A Systematic Review with Meta-analysis

IntroductionCancer-related pain is common and undertreated. Exercise is known to have a pain-relieving effect in non-cancer pain.ObjectivesThis systematic review aimed to evaluate (1) the effect of exercise on cancer-related pain in all cancers, and (2) whether the effect of exercise differed according to exercise mode, degree of supervision, intervention duration and timing (during or after cancer treatment), pain types, measurement tool and cancer type.MethodsElectronic searches were undertaken in six databases to identify exercise studies evaluating pain in people with cancer, published prior to 11 January 2023. All stages of screening and data extraction were conducted independently by two authors. The Cochrane risk of bias tool for randomised trials (RoB 2) was used and overall strength of evidence was assessed using the GRADE approach. Meta-analyses were performed overall and by study design, exercise intervention and pain characteristics.ResultsIn total, 71 studies reported in 74 papers were eligible for inclusion. The overall meta-analysis included 5877 participants and showed reductions in pain favouring exercise (standardised mean difference - 0.45; 95% confidence interval - 0.62, - 0.28). For most (> 82%) of the subgroup analyses, the direction of effect favoured exercise compared with usual care, with effect sizes ranging from small to large (median effect size - 0.35; range - 0.03 to - 1.17). The overall strength of evidence for the effect of exercise on cancer-related pain was very low.ConclusionThe findings provide support that exercise participation does not worsen cancer-related pain and that it may be beneficial. Better pain categorisation and inclusion of more diverse cancer populations in future research would improve understanding of the extent of benefit and to whom.PROSPERO registration numberCRD42021266826.