Guideline-Based Physical Activity and Survival Among US Men With Nonmetastatic Prostate Cancer

Abstract

The survival impact of adhering to current physical activity guidelines after prostate cancer diagnosis is unknown. We therefore emulated a target trial of guideline-based physical activity interventions and 10-year survival among US men with nonmetastatic prostate cancer. We used observational data on 2,299 men in the Health Professionals Follow-up Study who were diagnosed with nonmetastatic prostate cancer from 1998 to 2010 and were free of conditions that might have precluded participation at baseline (first postdiagnostic questionnaire). We estimated their survival under several guideline-based physical activity interventions starting at baseline and ending at the development of conditions limiting physical ability. We adjusted for baseline and time-varying risk factors for death using the parametric g-formula. Compared with the observed 15.4% mortality risk, the estimated 10-year risks of mortality were 13.0% (95% confidence interval (CI): 10.9, 15.4) and 11.1% (95% CI: 8.7, 14.1) for ≥1.25 hours/week and ≥2.5 hours/week of vigorous activity, respectively, and 13.9% (95% CI: 12.0, 16.0) and 12.6% (95% CI: 10.6, 14.7) for ≥2.5 hours/week and ≥5 hours/week of moderate activity, respectively. We estimated that these men would have experienced clinically meaningful reductions in mortality had they followed current physical activity recommendations until the development of conditions limiting physical ability. These findings may help guide clinical recommendations for prostate cancer patients and the design of future randomized trials.

Keywords: causal inference; cohort studies; lifestyle; parametric g-formula; physical activity; prostate cancer; survival.

Figure 1.

Selection of participants for a study of physical activity and survival among men with nonmetastatic prostate cancer, Health Professionals Follow-up Study, 2000–2014. Baseline refers to the return date of the first questionnaire after prostate cancer diagnosis. ALS, amyotrophic lateral sclerosis; CHF, congestive heart failure; MI, myocardial infarction.

Figure 2.

Estimated survival curves under hypothetical physical activity strategies among men with nonmetastatic prostate cancer, Health Professionals Follow-up Study, 2000–2014. All strategies excused men from following the recommended physical activity levels after development of functional impairment, metastasis, myocardial infarction, stroke, congestive heart failure, or amyotrophic lateral sclerosis. A) ≥1.25 hours/week of vigorous activity or ≥2.5 hours/week of moderate activity; B) ≥2.5 hours/week of vigorous activity or ≥5 hours/week of moderate activity.