Understandable your worry; doesn't make it easier.
We have been traumatized by our PSA (AKA prostate specific anxiety).
In my case , I trust that the salvage radiation did its job and the ADT assisted.
And while I was very glad to complete the ADT portion of the treatment, I was worried every 3 mos thereafter whether the ADT effect had ended and would my PSA rise again.
Well my PSA remains undetectable 2 years after completing ADT.
And I hope for a long remission, but believe that there is continued and additional treatment available if/when I recurr.
And enjoy my current good health. That's the best I can do and that's a great gift.
Best wishes