Your question: "I have been reading that a PSA of < 0.2 (Nadir point) within 6-12 months means a good long term outcome. So my question is: what PSA to expect in 3 months after ending Radiation in order to predict a better outcome?"
1. This was my experience 3 months and 6 months after ending radiation: 0.36 and 0.22 PSA levels, respectively.
2. I asked my radiation oncologist if PSA 0.22 was my nadir already? She said no, the nadir will be the lowest reading before PSA starts to rise.

I was already two weeks off Orgovyx when I had my PSA test 6 months after radiation (SBRT), so it could have been artificially low, with Orgovyx not yet fully flushed out of my system. On my next PSA test, which will be 9 months already after radiation, if the reading is below 0.22 then the lower value can be my nadir. If gthe January 2026 value will be higher, then my nadir will be 0.22 the last value before PSA rise.

My oncologist said it will not be a surprise if my PSA will rise because I would have been four months off Orgovyx by then, and my testosterone would also have been higher. However, if testosterone had not risen high enough to match the increase in PSA, then it is something to be looked into. I am prepared for the possibility that my PSA will be going up in the next little while then start going down again.

I was comparing notes with another in our brotherhood here