Individuals affected by childhood cancer may experience long-term cognitive impairments. Although exercise has been recommended for other cancer-related symptoms, the effect of physical activity on cognitive functioning in those affected by childhood cancer remains unknown. This systematic review aimed to estimate the effects of physical activity interventions compared to no intervention or usual care on cognitive function in people affected by childhood cancer.
Seven electronic databases were searched for randomised (RCTs) and quasi-randomised controlled trials, and non-randomised studies of interventions (NRSIs). There were no language or date restrictions. Eligible studies included individuals diagnosed with cancer at age 0-19 who received or are receiving cancer treatment. The intervention could be any frequency, intensity, volume, duration, or type of exercise or physical activity and delivered in any setting (e.g., gym). Control participants either had no treatment or usual care. The primary outcome of interest was performance on any standardised and objective academic or neuropsychological test of cognitive function. Outcomes related to cognitive function were categorised into 6 domains: complex attention, executive function, learning and memory, language, perceptual-motor function, and social cognition. Two independent reviewers screened for eligible studies, data extraction, assessment of risk of bias and certainty of evidence. Risk of bias was assessed using the Cochrane Risk of Bias Tool 2 for randomised and quasi-randomised controlled trials. Certainty of evidence was assessed for each outcome using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. A meta-analysis pooled all trials using a random-effects model to estimate the standardised mean difference (Hedges’ g) between the intervention and control conditions at the end of the intervention period. A composite score was calculated for each study to determine the overall intervention effect on general cognitive performance, which was used in the meta-analysis of the primary outcome.
Twenty-two studies were included in the review (n = 1,277). The median age at recruitment was 12 years (IQR 11-14), and the median time since treatment completion was 2.5 years (IQR -1.1-3.0). Interventions included aerobic, strengthening, and/or coordination-based exercises, with a median period of 12 weeks (IQR 10.24). Sessions lasted a median duration of 45 minutes (IQR 40-60) across a median of 3 days/week (IQR 2.5-5.0). Adverse events were reported in two studies, of which nine events were noted (minor wrist cut, muscle strain, nausea, vomiting, drop in systolic blood pressure, dizziness, and nosebleed).
Five randomised controlled trials (n = 245) were included in the meta-analysis of the primary outcome. No RCT in the primary outcome meta-analysis was considered high risk of bias. There was moderate certainty evidence that physical activity resulted in small-to-moderate improvements in objective tests of cognitive function compared with control (SMD 0.40, 95% CI 0.07 to 0.73).
Physical activity and exercise interventions improve cognitive function in people who had childhood cancer. Future research should explore the optimal frequency, intensity, volume, duration, and type of physical intervention across different patient characteristics (e.g., type of cancer) for improving cognitive function.
Bernal JDK, Recchia F, Yu DJ, et al. Physical activity and exercise for cancer-related cognitive impairment among individuals affected by childhood cancer: a systematic review and meta-analysis. Lancet Child Adolesc Health. 2023;7(1):47-58. doi:10.1016/S2352-4642(22)00286-3