Safety, feasibility and effect of exercise following cancer: do findings differ according to survival prospects?

Aims: Cancer types with poorer prognosis are associated with later-stage at diagnosis, more invasive/intensive treatment and more severe side effects; factors which may influence exercise safety, feasibility and efficacy. The purpose of this work was to compare the results of two independent meta-analyses conducted to assess the safety, feasibility and effects of exercise following lung cancer (LC) and colorectal cancer (CRC), with these two common cancers being associated with 5-year survival rates of 18% and 70% respectively. Methods: Registered (PROSPERO) database searches were undertaken to identify eligible randomised, controlled, exercise trials. The PEDro scale was used to assess risk of bias. Adverse Events (AE) were assessed using the AE Common Terminology Criteria, feasibility was assessed by calculating exercise adherence rates, and meta-analyses were undertaken to evaluate AE risk between exercise and usual care (risk difference; RD), and effects on health outcomes (standardised mean difference; SMD). Results: 32 LC (n=2109) and 19 (n=1293) CRC trials were included. AE risk for both cancer types was low (LC: RD=-0.01 [91% CI=–0.02, 0.01], p=0.31; CRC: RD=0.00 [95% CI:–0.01, 0.01], p=0.92). Feasibility appeared slightly better for CRC vs LC: adherence rate: 86% (42-91%) vs 80% (44-100%), respectively. Significant beneficial effects (p<0.05) of exercise were observed for a range of health outcomes (SMD range: 0.21-0.66). However, poor safety reporting, unclear sample representativeness and a lack of effectiveness trials were identified as key limitations. Conclusion: These findings support exercise post-cancer as being safe, feasible and effective, irrespective of prognosis. Nonetheless, the limitations reinforce ESSA’s cancer and exercise position statement recommendations, which include the application of evidence, clinical experience and exercise principles in the individualised, targeted exercise prescription to cancer patients.