Effects of exercise-conditioned serum on cancer cell behaviour in vitro: a systematic review and meta-analysis

Physical activity reduces cancer risk but the underlying mechanisms remain unclear. We meta-analysed the effects of acute exercise and exercise training on serum-stimulated cancer cell behaviours in vitro. Systematic searches of PubMed, Scopus and SPORTDiscus up to February 2021 revealed 8 studies reporting 61 effect sizes eligible for meta-analysis. Standardised mean differences (SMDs) between exercise-conditioned serum and resting serum were pooled using random-effects models. Acute exercise-conditioned serum significantly reduced cancer cell growth (SMD -1.31, 95% CI -1.77 to -0.86, p