Thanks for posting this. I'm still in remission since my SRT, maybe always will be, though the nomograms tell me it will probably be back. But my plan is if it comes back, to postpone any ADT for as long as possible--until identifiable mets or at least a PSA well into double digits. I'm not convinced that starting earlier will prolong my life. But I am certain that starting earlier will degrade my quality of life. I'm not questioning anyone else's choice. But I'm guessing at worst I'd be sacrificing some months of life in exchange for a few years of better quality life. But that's just how I plan to play the cards if they are dealt--not to say that I'm playing them right.
I completely agree with your approach, about when/if you should need ADT. This has been my game plan, and my oncologist's game plan from the time my SRT failed fast. A big difference of course, mine has failed, and due to all my other post surgical and post radiation issues, I have already been dealing with a severely diminished QOL situation for over 4 years now. My oncologist doesn't see the point of hitting ADT, until he sees firm evidence that the timing is right, as you said, evidence of identifiable mets. That's why we do the PET scan yearly, and other scans as needed.
And before I forget, I hope you never have to be in the situation to have to need ADT, the nomograms may or may not be an accurate predictor for what lies ahead for you. Meanwhile, enjoy what you can out of life, minus the ADT unless truly needed.