Effect of Post-diagnosis Physical Activity on Breast Cancer Recurrence: a Systematic Review and Meta-analysis

Breast cancer (BC) recurrence dramatically decreases 5-year survival, which causes a fear of BC recurrence among a majority of BC survivors. Evidence is currently inconsistent on whether post-diagnosis recreational physical activity (rPA) can prevent BC recurrence due to the small number of included studies, as well as methodological heterogeneity among the studies. This systematic review aimed to clarify the association between post-diagnosis rPA and the risk of BC recurrence, by conducting a meta-analysis while controlling for the categories of rPA across the existing studies.

Prospective cohort studies were searched, and five studies were eligible for the meta-analysis. Of 10,094 patients with BC, 1561 had recurrence during the follow-up period ranging from 12 to 156 months. The meta-analysis revealed that patients whose post-diagnosis rPA was ≥ 7.5 metabolic equivalents (MET-h/week) had a lower BC risk than patients whose rPA was 0-3 MET-h/week (hazard ratio [HR], 0.65; 95% CI, 0.58-0.73, p < 0.00001, I² = 0%). The review indicated that a post-diagnosis rPA of ≥ 7.5 MET-h/week could reduce the risk of BC recurrence by 35%. Although it is necessary to investigate randomized controlled studies in the future, this result will strengthen strategies for the care and/or treatment of patients after BC and can motivate BC survivors to participate in rPA programs after BC diagnosis.