Hello rbman - The concept of intermittent ADT seems to be gaining some popularity and your situation (local recurrence?) seems to be a good situation to try a pause and monitor.
https://www.nejm.org/doi/full/10.1056/nejmoa1212299https://jamanetwork.com/journals/jamaoncology/fullarticle/2436836My wife had a oligometastatic local recurrence of BCa and had it zapped. I keep asking her if the doctor would consider dropping HT and oral chemo drugs at some point after 4 years which is always rejected. I think the issue tends to be that women do not have such a precise tracking tool as PSA for recurrence and it could get out of hand quickly before any blood tests or scans would find anything conclusive.
Heck, there is possibility of PCa returning for every treated patient at any time so the fact that you had an recurrence certainly does not yield less probability than anyone else. I think your idea is good one and should be explored. Not to rehash my old story but my Dad had a recurrence after brachy in his mid-late 80's, went on 2 years of ADT, dropped PSA to undetectable, and passed at 96 from heart failure. He died with PSA of at least 9 due to an accidental test as he/they stopped testing shortly after ADT.