Selective loss of levator ani and leg muscle volumes in men undergoing androgen deprivation therapy.

Abstract

Androgen deprivation therapy (ADT) for prostate cancer (PCa) leads to a selective loss of leg muscle function during walking. Rodent models of ADT demonstrate that levator ani is exquisitely androgen sensitive. To determine whether the high androgen responsiveness of the levator ani muscle documented in rodents is evolutionarily conserved, and ADT is associated with a selective loss in leg muscle volumes. Prospective longitudinal case-control study. Tertiary referral hospital. 34 men newly commencing ADT and 29 age-matched PCa controls. Muscle volumes (litres) of levator ani, and of primary muscles involved in walking (iliopsoas, quadriceps, gluteus maximus, gluteus medius, calf). Compared to controls over 12 months, men receiving ADT had a mean reduction in total testosterone from 14.1 to 0.4nmol/L and demonstrated greater decreases in levator ani (MAD -0.005litres [-0.007, -0.002], p=0.002, -16% of initial median value), gluteus maximus (MAD -0.032litres [-0.063, -0.002], p=0.017, -5%), iliopsoas (MAD -0.005litres [-0.001, 0.000], p=0.013, -5%) and quadriceps (MAD -0.050litres [-0.088, -0.012], p = 0.031, -3%). No significant differences were observed in gluteus medius and calf muscles. Androgen responsiveness of levator ani appears to be evolutionarily conserved in humans. ADT selectively decreases volume of muscles that support body weight. Interventional strategies to reduce ADT-related sarcopenia and sexual dysfunction should assess whether targeting these muscle groups, including the pelvic floor improves clinical outcomes.