Effects of exercise on disablement process model outcomes in prostate cancer patients undergoing androgen deprivation therapy.

Abstract

Androgen-deprivation therapy (ADT) results in adverse physiologic, metabolic, and functional side effects that may accelerate functional limitations in patients with prostate cancer (PC). Although exercise improves muscular strength and functional performance, the extent to which exercise yields similar improvements in other disablement process outcomes in men on ADT has yet to be systematically evaluated. To explore whether exercise results in comparable improvements in physiologic and structural body system impairment, functional limitation (relating to basic physical or mental actions), and physical disability domain outcomes identifed in the Disablement Process Model (DPM) in PC patients who are receiving ADT. Data from studies of exercise interventions in men on ADT were extracted on impairment, functional limitation, and physical disability domain outcomes. The average of weighted, bias-corrected effect sizes were calculated for each outcome and compared across domains. A total of 9 studies (6 randomized controlled trials, 3 uncontrolled trials) conducted with 684 PC patients met the inclusion criteria. Exercise yielded heterogeneous effect-size improvements in physical impairments, ranging from large improvements in muscular strength (d = .74; 95% CI, .14-1.47) and endurance (d = 2.64; 95% CI, 1.08-2.84), to small improvements in body composition measures (d = .12; 95% CI, -.52-.68). Whereas exercise resulted in meaningful effect-size improvements in functional limitation domain outcomes (d = .39; 95% CI, -.42-1.01), fndings from the 4 studies that assessed a physical disability, domain outcomes revealed only small improvements (d = .10; 95% CI, -.44-.43) in these outcomes. Collectively, exercise consistently results in meaningful improvements in physical impairments and functional limitations in basic physical tasks. However, to date, few studies have evaluated the effects of exercise on physical disability domain outcomes, and the results suggest that the effects of exercise on physical disability measures are of a smaller magnitude relative to those observed for impairment and functional limitation domain outcomes.