A Pooled Analysis Of Six Cohorts: Physical Activity And Survival In Breast, Colon, And Prostate Cancer

Achieving at least 7.5 metabolic equivalent task hours of moderate-to-vigorous physical activity (MVPA) per week is recommended for cancer survivors, but its impact on overall survival, particularly for those inactive before diagnosis, remains unclear. PURPOSE: To estimate associations of meeting MVPA guidelines pre- and post-diagnosis with cardiovascular disease (CVD) and cancer survival in breast (B), colon (C), and prostate (P) cancer survivors. METHODS: Data from six cohort studies were pooled. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models with delayed entry (time scale started at diagnosis date) and pooled via random-effects meta-analysis. Participants were categorized by adherence to MVPA guidelines: meeting/exceeding guidelines pre- and post-diagnosis, meeting/exceeding pre-diagnosis only, meeting/exceeding post-diagnosis only, and not meeting guidelines at either timepoint (referent). Estimates were made at least one year before/after diagnosis. RESULTS: The sample included 100,994 cancer survivors (mean age at diagnosis = 68 years, 73% women, 93% White/Non-Latino, 37% B, 14% C, 49% P), with 52,445 deaths during 11.4 years of follow-up. Pre-diagnosis MVPA was assessed 9.8 years prior, and post-diagnosis MVPA 3.0 years after diagnosis. Survivors meeting MVPA guidelines at both timepoints had lower CVD mortality risk [B: HR = 0.74, 0.58-0.94; C: HR = 0.58, 0.40-0.83; P: HR = 0.58, 0.45-0.75]. Meeting guidelines post-diagnosis only also reduced CVD mortality risk [B: HR = 0.73, 0.56-0.96; C: HR = 0.62, 0.42-0.92; P: HR = 0.62, 0.51-0.75]. Similar results were found for cancer mortality: meeting guidelines at both timepoints was associated with 24-34% reduced risk [B: HR = 0.76, 0.68-0.84; C: HR = 0.68, 0.54-0.86; P: HR = 0.66, 0.53-0.80]; post-diagnosis only with 28-30% reduced risk [B: HR = 0.72, 0.65-0.80; C: HR = 0.71, 0.58-0.86; P: HR = 0.70, 0.57-0.86]. Pre-diagnosis only adherence was not associated with survival outcomes. CONCLUSIONS: Meeting MVPA guidelines post-diagnosis, regardless of pre-diagnosis adherence, was related to lower CVD and cancer mortality in B, C, and P survivors. The potential for reverse causation warrants further investigation. Maintaining or increasing MVPA post-diagnosis may improve survival.