It appears well established now that, in general for APC, intermittent ADT (IADT), or "taking breaks" from ADT drugs is "not inferior" to continuous androgen deprivation (CADT).
And protocols for the timing of starting and stopping such ADT breaks are being refined.
However, from what I have found, in none of the studies did they monitor and stratify men for their testosterone recovery during the time off of ADT. This is surprising since the whole reason for doing IADT is to allow some period of testosterone recovery to normal, or at least physiologically beneficial levels.
If the whole idea of intermittent ADT is to have some period of recovered testosterone, which does have significant benefits for the body as well as QOL, then that should be considered. Some men recover T production within a few months, but many not until a year or perhaps never. So to even-the-playing-field for those who do not recover T production while on break, it is reasonable to consider physiologic (normal levels) of testosterone replacement (TRT) during this time, as long as normal monitoring of PSA and scans continue.
Earlier this year, I was researching this topic to argue for intermittent testosterone replacement for myself for my severe sarcopenia (loss of muscle mass that resulted in a collapsed vertebra and spinal nerve compression, and severe hypogonadal symptoms ranging far beyond fatigue, hot flushes and loss of libido. I encountered three different experienced urologic oncologists who raised this same point, suggesting testosterone replacement should be considered not different from normal testicular recovery of T production.
You would have to argue this with many MOs who may not take this into consideration. My sarcopenia (body muscle wasting) and hypogonadal symptoms have improved wonderfully from just a few months of testosterone replacement this year.