Grading the Evidence for Physical Activity and any Outcome in Cancer Survivors: an Umbrella Review of 740 Meta-analytic associations.

Background: To contribute to the refinement of future physical activity (PA) guidelines, which have remained mostly generic until now, we performed an umbrella review of meta-analyses for PA in cancer survivors.

Methods: Medline and Scopus databases were searched in January 2024 for systematic reviews and meta-analyses on the association/effect of any type of PA in every cancer type and for any studied outcome. Statistically significant meta-analyses were categorized into four evidence groups (strong, highly suggestive, suggestive, weak) using pre-established grading criteria.

Results: A total of 102 publications reporting 740 meta-analytic associations were identified, including breast (n=427), prostate (n=104), hematological (n=58), colorectal (n=79) and lung (n=54) cancer survivors. Overall, 401 (54%) associations were nominally statistically significant, of which 16 were categorised as strong, 10 as highly suggestive, and 93 as suggestive evidence. In breast cancer, there was strong or highly suggestive evidence that post-diagnosis PA is associated with lower all-cause mortality, recurrence, cancer-related fatigue, depression, and higher mental health, body strength, aerobic capacity, and weight loss. In prostate cancer, strong evidence was identified for the positive association of PA with cardiovascular fitness, quality of life and fatigue amelioration. In colorectal cancer, strong and highly suggestive evidence supported the association of PA with lower all-cause mortality. In lung cancer, strong evidence supported the association of preoperative combination of breathing exercise and PA with reduced length of hospital stay.

Conclusion: This grading of the entirety of the available evidence can facilitate robust introduction of targeted exercise prescription in oncology care as standard practice.