Testosterone recovery after androgen deprivation therapy

Purpose: Finite courses of androgen deprivation therapy (ADT) are often utilized in men undergoing treatment for prostate cancer. Previous evidence suggests that timing of testosterone (T) recovery can be variable after ADT. Recently, an oral gonadotropin releasing-hormone (GnRH) antagonist, relugolix, has demonstrated more rapid T recovery than injectable GnRH agonists such as leuprolide. In this study, we sought to evaluate patient characteristics associated with T recovery in patients undergoing ADT of defined duration. Materials and Methods: The Northwestern Enterprise Data Warehouse was queried for men with prostate cancer who completed a course of ADT and subsequently had a testosterone lab performed. Testosterone recovery was evaluated for levels that reached above castrate (T > 50 ng/dl), partial recovery (T > 150 ng/dl), and full recovery (T ≥ 300 ng/dl). Results: 388 men who received finite courses of ADT were identified (348 receiving leuprolide, 36 receiving relugolix, and 4 receiving degarelix). In multivariable Cox regression analysis, men who were prescribed GnRH antagonists (HR = 3.74, CI = 2.53–5.53, P ≤ 0.001) and who were younger (HR for 1 year increase in age = 0.96, CI = 0.95–0.98, P < 0.001) were more likely to achieve partial recovery. In a subgroup analysis, men who received extended ADT courses (>12 months) with a GnRH agonist had lower rates of partial T recovery (HR = 0.58, CI = 0.41–0.81, P = 0.001). Conclusion: T recovery after ADT is variable with roughly one sixth of men remaining castrate. GnRH antagonist use and younger age are associated with higher rates of T recovery after ADT. Longer ADT courses were associated with worse T recovery rates.