Recreational Physical Activity in Relation to Prostate Cancer–specific Mortality Among Men with Nonmetastatic Prostate Cancer

Abstract

BackgroundLarge prospective cohort studies need to confirm the associations between recreational physical activity (PA), including the most common type—walking, and prostate cancer–specific mortality (PCSM) among prostate cancer patients. ObjectiveTo investigate the associations of recreational PA, reported before and after diagnosis, with PCSM, overall and by tumor risk category. Design, setting, and participantsIn a prospective cohort study conducted in the USA, men diagnosed with nonmetastatic prostate cancer between 1992/1993 and June 2011 were followed for mortality until 2012. Patients were included in pre- (n=7328) and/or postdiagnosis (n=5319) analyses. Outcome measurements and statistical analysisCox proportional hazards models were used to assess PCSM with recreational PA. Results and limitationsA total of 454 and 261 prostate cancer deaths occurred during pre- and postdiagnosis follow-up, respectively. Prior to diagnosis, engaging in ≥17.5 metabolic equivalent hours per week (MET-h/wk) of recreational PA, compared with 3.5–<8.75 MET-h/wk, was associated with a significant 37% lower risk of PCSM (hazard ratio: 0.63, 95% confidence interval: 0.43–0.91, p trend=0.03) only among men with lower-risk tumors (Gleason score 2–7 and T1–T2; p interaction=0.02). A similar result was seen for walking but not for other recreational PA. After diagnosis, the same comparison (≥17.5 vs 3.5–<8.75 MET-h/wk) was associated with a significant 31% lower risk of overall PCSM (hazard ratio: 0.69, 95% confidence interval: 0.49–0.95, p trend=0.006), which did not differ by tumor risk category. Postdiagnosis walking had a suggestive inverse association with PCSM (p trend=0.07). These results were observational and may not be generalized to patients with metastatic prostate cancer. Residual confounding due to a higher screening rate among men with lower-risk tumors cannot be ruled out. ConclusionsThe findings provide additional evidence for prostate cancer survivors to adhere to PA recommendations, and support clinical trials of exercise among prostate cancer survivors with progression or mortality as outcomes. Patient summaryIn a large follow-up study of men diagnosed with nonmetastatic prostate cancer, those who exercise more after diagnosis had a lower risk of dying from prostate cancer.