This plot shows the time after stopping Lupron ADT for the testosterone to recover to the original level for 50% of men, plotted versus Duration of ADT treatment (4 or 24 months). The longer the duration of ADT, the longer it takes to recover the original testosterone level, which makes sense. For ADT of 4 months, 50% of men will fully recover their testosterone in 5 months. For ADT of 4 months, 50% of men will fully recover their testosterone in 24 months. Roughly speaking, on average, the T-recovery time equals the duration of ADT.
Testosterone Recovery after stopping ... - Prostate Cancer N...
Testosterone Recovery after stopping ADT -2
Wonder if the effectiveness against the PCa continues for the same duration.
That's a complicated question.
Initially, after stopping ADT, the testosterone levels will initially remain below the saturation level of 250 ng/dL for some period of time. These low values of testosterone / DHT will continue to beneficially "starve" PCa cells even after stopping ADT. But, at above 250 ng/dL, the androgen receptors become saturated and will no longer be killed by larger levels of testosterone. So, any increase in testosterone beyond 250 will not be able to effectively kill PCa cells. At that point, there is no residual left-over beneficial effect of ADT.
See the papers by A. Morgentaler at Harvard about the saturation effect of testosterone.
That's why one should consider waiting to start testosterone replacement therapy (TRT) until after you get above 250 ng/dL, (because the beneficial effects of ADT will have worn off by then). After that point, you could use TRT to reach 700-1000 ng/dL, for good health and quality of life.
As always, the decision when to start TRT after stopping ADT is a trade off between killing more cancer cells and quality of life. The issue is diminishing returns...how many percentage points in survival metrics do you want to gain after stopping ADT, versus dealing with the bad side effects of low testosterone?
Men should check their total and free testosterone often during this transition period.
Bob