Oral Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Background: Loss of muscle mass and gain in fat mass occurs in men undergoing androgen deprivation therapy (ADT) for prostate cancer. Whether body composition improves after cessation of ADT is not known.

Methods:  We conducted a prospective case-control study over 4 years (2 years on ADT, 2 years off ADT) involving 34 men newly commencing ADT and 29 age- and radiotherapy-matched prostate cancer controls. Serum sex steroid levels were measured and body composition was assessed using dual x-ray absorptiometry. To determine differences between groups over time, a clustered linear regression model was performed which accounted for baseline values.

Results: We report preliminary results for 10 men in the ADT group and 8 controls. All patients recovered total testosterone levels to a normal range (median 15.4 nmol/L) by two years post therapy. Compared with controls, the ADT group gained the majority of fat mass in the first 12 months of ADT, which then plateaued. At 4 years (2 years after ADT cessation), there was no recovery in gained fat mass with between group difference +4331g [2106,6556], p = 0.002. Lean mass decreased throughout duration of ADT but improved after cessation. At 4 years, lean mass in the ADT group compared with controls was not significantly different from baseline.

Conclusion: These preliminary findings indicate that, fat mass once gained, does not improve despite recovery of testosterone levels. Whether the recovery of lean mass mitigates some of the deleterious effects of persistent  adiposity requires further study. These results emphasise the importance of mitigating fat gain in the early period after commencement of ADT to minimise cardiovascular morbidity and mortality.