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.