The effects of physical activity on overall survival among advanced cancer patients: a systematic review and meta-analysis

Background The survival rates of advanced cancer patients remain low despite clinical therapy advancements. However, physical activity showed promising effects in improving cancer outcomes. This review aimed to systematically evaluate and synthesize the effects on overall mortality of post-diagnosis physical activity in advanced cancer patients. Methods A systematic search of six English databases (PubMed, EMBASE, CINAHL, PsycINFO, The Cochrane Central Register of Controlled Trials, and SPORTDiscus) was conducted from their inception up to 3 February 2021. The association of physical activity with survival was evaluated by combining study-specific hazard ratios with random-effects meta-analysis models. Results Eleven studies were identified. Compared with the reference group, higher-level physical activity was not significantly associated with a lower risk of earlier mortality in advanced cancer patients (InHR = - 0.18, 95% CI, - 0.36 to 0.01). When separated by study type, a higher level of physical activity in non-randomised trials was significantly associated with reduced mortality risk (InHR = - 0.25, 95% CI: - 0.44, - 0.06). However, in randomised trials, engaging in exercise was not significantly associated with a lower mortality risk compared with the control group (InHR = 0.08, 95%CI: - 0.17, 0.32). Conclusions Discrepancies were uncovered in the effect of physical activity on overall survival in randomised and non-randomised trials. In non-randomised trials, a higher level of physical activity was significantly associated with a lower risk of mortality, whereas no significant effect on survival was observed during exercise interventions compared to the control in randomised trials. Considering the wider benefits of physical activity, exercise can still be recommended to improve outcomes for advanced cancer patients. Nevertheless, it might be too late for advanced cancer patients to start exercising for survival improvements, based on findings from randomised controlled trials.