When administering adjuvant RT to the prostate bed with concurrent ADT, do you start concurrently or prefer to administer the ADT first?

In the absence of evidence I turn to first principles. If the ADT were short-term and aimed towards improving local control, then I would start the ADT a good few months ahead of the radiation to maximize the synergy. However, if it was a high-risk case with ADT planned for a few years and the radiation was more of a "garnish", then I don't believe the timing is so important. If it was more convenient to give radiation and start ADT at around the same time then that would be fine as well.

In general when giving post-op RT with ADT, our usual practice is to follow the paradigm of 2 mo neoadjuvant, and 2+ mo concurrent which is what we do for the intact setting (following RTOG 8610, 9202). It probably does take some time to generate a full therapeutic effect of ADT including castrate levels of testosterone and potential immunity augmenting effects. However, it could be debated whether this need to wait is clinically important (RTOG 9413 tested the timing of ADT in the intact settin...