Radiotherapy before or during androgen-deprivation therapy does not blunt the exercise-induced body composition protective effects in prostate cancer patients: A secondary analysis of two randomized controlled trials.

ABSTRACT

BACKGROUND: Androgen deprivation therapy (ADT) contributes to lean mass loss and adiposity increases in prostate cancer patients. Radiotherapy during ADT might act synergistically and further worsen body composition. Previous investigations have shown that resistance training is an effective method of preserving body composition during ADT, however, most have not accounted for direct or indirect effects of other therapies, such as radiotherapy. Therefore, the purpose of this study was to examine training adaptations of the tissue composition in patients receiving radiation therapy (RT) prior or during ADT. METHODS: Analyses were performed by combining data from two previous trials for a total of 131 prostate cancer patients who underwent a combination of resistance and aerobic exercise training (N = 70, age 68.9 ± 6.6y, RT-before 13%, RT-during 14%) or usual care (N = 61, age 67.5 ± 7.9y, RT-before 16%, RT-during 20%) for 3 months upon ADT onset. Whole-body lean mass (LM), fat percentage and appendicular LM were determined by dual energy x-ray absorptiometry, and lower-leg muscle area and density by peripheral computed tomography at baseline (onset of ADT) and at 3 months post-intervention. Covariates included RT prior and during the intervention, demographic characteristics, physical symptoms, and chronic conditions. RESULTS: Radiotherapy before or during the intervention did not affect body composition. Only the usual care group experienced a significant decrease in whole-body LM (-994 ± 150 g, P < 0.001) and appendicular LM (-126 ± 19 g, P < 0.001), and an increase in whole-body fat percentage (1% ± 0.1%, P < 0.001). There was no change in lower-leg muscle area or density in either group. CONCLUSION: We suggest that radiation prior to and during ADT does not interfere with the beneficial effects of exercise training on body composition in men with prostate cancer.