Many men go on ADT short term either to improve the effectiveness of radiotherapy (i.e., neoadjuvant ADT) or as part of intermittent ADT, where they cycle on and off it. The reason for cycling is to reduce the side-effects of androgen suppression and to allow testosterone levels to recover. But, as the title above suggests, a very common question is: "How long should that recovery take?"
Researchers in Japan have explored this topic in a sample of 125 patients who received 6 months of neoadjuvant ADT followed by low-dose rate brachytherapy. Patients either received 1) GnRH agonist (goserelin or leuprolide), or 2) GnRH antagonist (degarelix) for six months. The researchers defined “normal” levels of total testosterone as 3.0 ng/mL, in accordance with the 2018 American Urological Association guidelines.
Results: Twelve months after stopping ADT, approximately half of the men had their total testosterone levels back to normal. Twenty-four months after stopping ADT, about 80% of patients’ testosterone levels had returned to normal. The median amount of time required to normalize total testosterone was 15 months.
The researchers found three factors associated with slower recovery of total testosterone levels: use of GnRH agonists (instead of the antagonist), higher body mass index, and a history of hypertension. The researchers noted that baseline testosterone levels rarely decrease with age for Japanese males in the age range of the patients in their study, and there may be racial differences in the pattern of decline in testosterone with age. As such, it is not known whether there are significant racial differences in the rates of testosterone recovery after stopping ADT. This warrants repeating this study in other populations.
To read the study abstract, see: https://www.ncbi.nlm.nih.gov/pubmed/32096413
Kato, Y., Shigehara, K., Kawaguchi, S., Izumi, K., Kadono, Y., & Mizokami, A. (2020). Recovery of serum testosterone following neoadjuvant androgen deprivation therapy in Japanese prostate cancer patients treated with low-dose rate brachytherapy. The Aging Male. Advance Online Publication. doi: 10.1080/13685538.2020.1731450