The effect of physical activity on health-related outcomes in children and adolescents with cancer: a systematic review and meta-analysis

Background: Although treatment-related adverse effects in children and adolescents with cancer are likely multifactorial, insufficient physical activity (PA) is a major contributor. However, evidence on the association between PA and adverse effects in these population remains limited. We aimed to estimate the effects of PA on health-related outcomes (HrO). Methods: We searched nine databases from inception to August 5, 2025, for randomized controlled trials evaluating the effects of PA on HrO in children and adolescents with cancer. Data extraction followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. Independent reviewers extracted study data, and a random-effects model was used to pool results. Two reviewers independently extracted data, assessed the risk of bias, and evaluated the quality of evidence. The primary outcomes included quality of life (QoL), exercise capacity, and cognitive function indicators, while secondary outcomes encompassed social function and body composition indicators, as well as PA intervention acceptability and safety. Results: The search identified 3,037 studies, only 24 met the eligibility criteria, including nine articles on children, five on adolescents, and ten on both groups. For primary outcomes, PA significantly improved fatigue (SMD = 0.66), muscle strength (SMD = 1.77), trunk muscle strength (SMD = 4.20), PA behaviour (SMD = 1.04), PA levels (SMD = 0.97), six-minute walk test (SMD = 0.62), cognitive function (SMD = 0.32), and executive function (SMD = 0.47); however, PA had no significant effect on QoL, the QoL scale, upper and lower body muscle strength, balance, flexibility, athletic performance, peak oxygen uptake, and depressive symptoms. Regarding secondary outcomes, PA significantly improved social function (SMD = 0.23) but had no significant effect on bone density, BMI, fat percentage, NK cells, or inflammatory factors. Additionally, moderator analysis showed that PA conditions and participant traits significantly affected the outcomes. Conclusions: In children and adolescents with cancer, PA can improve HrO, ultimately helping to reduce the disease burden. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251018626, identifier CRD420251018626.