The primary medications for ADT suppress testosterone production from the testes. Historically the goal has been to drive the serum testosterone levels down to below 50 ng/dL, which was considered “castrate levels” that could stop or slow the growth of prostate cancer (PCa) cells. That level is well below the serum level of 280 ng/dL, which is considered normal for men around the average age of those starting ADT. However, in the last decade or so it has been shown that an even lower level of T, of <20 ng/dL, proved better cancer control.
A new paper by Klotz and Tat looked a variety of studies done with one particular ADT agent, triptorelin, which is similar to Lupron, Eligard, and Zoladex, but used more commonly outside North America. The overall sample was 592 men with PCa and the study showed that the overall survival was better in the men, who achieved an even lower T serum level of <10 ng/dL. Simple conclusion—the lower the T, the better the control of systemic PCa.
But some PCa patients go on ADT short term to increase the effectiveness of radiotherapy. Many of them feel better when their T levels are back in the normal range, and they are off androgen suppressing medications. That raised the question of how well T serum levels recovery after stopping ADT and does it matter for the patients’ health, if not full recovery is achieved.
A second new paper looked at the reverse question to the Klotz and Tat study. The authors of this second paper had data from 1553 men, who had their T levels measured within 12 months of discontinuing ADT. In that first year, 75% of the men did not achieve normal T levels.
It was already known that most men do not fully recover T levels after extended ADT, but what is new here is that the authors also showed that those men, who showed poor T recovery, were also more likely to start to develop type 2 diabetes.
Whether one is going on ADT or coming off it, these two studies suggest that patients should request that the physicians, who manage their PCa, request not just regular PSA tests, but samples to track their T levels.
References:
Klotz, L., & Tat, T. (2023). Testosterone nadir and clinical outcomes in patients with advanced prostate cancer: Post hoc analysis of triptorelin pamoate Phase III studies. BJUI Compass.
Preston, M. A., Hong, A., Dufour, R., Marden, J. R., Kirson, N. Y., Gatoulis, S. C., ... & Morgans, A. K. (2024). Implications of Delayed Testosterone Recovery in Patients with Prostate Cancer. European Urology Open Science, 60, 32-35.