Resistance exercise reduces body fat and insulin during androgen-deprivation therapy for prostate cancer

Purpose/Objectives: To determine whether exercise could reduce biomarkers of cancer progression in prostate cancer survivors (PCSs) on androgen-deprivation therapy (ADT). Design: Randomized, controlled trial. Setting: Oregon Health and Science University School of Nursing. Sample: 51 PCSs randomized to one year of resistance and impact training or a stretching control group. Methods: The authors investigated changes in body composition and cancer-related biomarkers, and the influence of age and fat loss on changes in biomarkers. Main Research Variables: Body composition (total fat, trunk fat, and lean mass), insulin, insulin-like growth factor-1, and sex hormone-binding globulin. Findings: In the 36 PCSs with baseline and 12-month data, total fat (p = 0.02) and trunk fat (p = 0.06) mass decreased in the training group compared to gains in controls. Loss of total and trunk fat each mediated the relationship between groups and one-year change in insulin (p < 0.05). Age moderated the insulin response to exercise where insulin reductions were smaller with increasing age (p = 0.03). Conclusions: Resistance and impact exercise may reduce body fat among PCSs undergoing ADT, in turn exerting an insulin-lowering effect. Implications for Nursing: Nurses should counsel PCSs to exercise to reduce the risk of obesity and associated conditions, including cancer progression.