Note that Nubeqa (Darolutimide) has recently been FDA-approved for metastatic castrate sensitive prostate cancer: https://youtu.be/qFK23Na9RfY?si=nMaMKVJx1hcyny7L
So, that’s now a possible option for you to use with ADT.

As for the technical definition of biochemical recurrence (BCR) following initial radiation - a PSA rise of 2.0 ng/mL above nadir (called the Phoenix Criteria) - was established in 2005 (20 years ago!) when modern imaging techniques (like PSMA-PET scans) that can detect recurrence at lower PSA levels were not available. It’s now known that BCR can occur following initial radiation well before that “2 points over nadir” threshold is reached.

The Phoenix Criteria served Ira purpose well - to differentiate true cancer recurrence from PSA fluctuations in order to prevent overtreatment, but is now likely outdated, with today’s earlier and more effective diagnostic techniques.

(I had initial treatment of 28 sessions of proton radiation during April-May 2021. PSA now varies between 0.350-0.550; my most recent PSA was 0.473. My medical oncologist and I have agreed that should I have three successive PSA increases, that she’ll schedule a PSMA PET scan. So far, three successive increases has not happened.)

Note also that the lower the PSA, the less sensitive PET scans are at detecting prostate cancers. (See attached graphic.)