Resistance Exercise Counteracts the Impact of Androgen Deprivation Therapy on Muscle Characteristics in Cancer Patients

Context Androgen deprivation therapy (ADT) forms the cornerstone in prostate cancer (PCa) treatment. However, ADT also lowers skeletal muscle mass. Objective To identify the impact of ADT with and without resistance exercise training on muscle fiber characteristics in PCa patients. Methods Twenty-one PCa patients (72 +/- 6 years) starting ADT were included. Tissue samples from the vastus lateralis muscle were assessed at baseline and after 20 weeks of usual care (n = 11) or resistance exercise training (n = 10). Type I and II muscle fiber distribution, fiber size, and myonuclear and capillary contents were determined by immunohistochemistry. Results Significant decreases in type I (from 7401 +/- 1183 to 6489 +/- 1293 mu m(2), P < .05) and type II (from 6225 +/- 1503 to 5014 +/- 714 mu m(2), P < .05) muscle fiber size were observed in the usual care group. In addition, type I and type II individual capillary-to-fiber ratio (C/Fi) declined (-12% +/- 12% and -20% +/- 21%, respectively, P < .05). In contrast, significant increases in type I (from 6700 +/- 1464 to 7772 +/- 1319 mu m(2), P < .05) and type II (from 5248 +/- 892 to 6302 +/- 1385 mu m(2), P < .05) muscle fiber size were observed in the training group, accompanied by an increase in type I and type II muscle fiber myonuclear contents (+24% +/- 33% and +21% +/- 23%, respectively, P < .05) and type I C/Fi (+18% +/- 14%, P < .05). Conclusion The onset of ADT is followed by a decline in both type I and type II muscle fiber size and capillarization in PCa patients. Resistance exercise training offsets the negative impact of ADT and increases type I and II muscle fiber size and type I muscle fiber capillarization in these patients.