Well, I totally understand your aversion to the saturation bombing concept of salvage radiation; lots of innocent bystanders but a lot of bad guys too…
When I had my PET PSMA something showed up at the edge of the femur; my radiologist said it was a natural biologic process - inflammation or bone cyst. When I asked him how did he know it was NOT prostate cancer metastasis, he said that for bones to show metastasis, other soft tissue areas much closer to the prostate bed would have to show up on the scan as well - even brighter in fact; I did not have any of that and evidently, neither did you. Also, my post surgical PSA never got higher than .18, which he also said ruled out bone metastasis….what was your pre surgical PSA and Gleason score? That might give you an indication of how aggressive your cancer was (absent a Decipher score).
But what gives me pause is your PSA bounce after SBRT. If those lesions were not PCa, why the bounce? And if not PCa, what are they??
If everything else is normal, you have active prostate cancer somewhere in your body (as jeffmarc pointed out) - and even salvage radiation, which usually targets the prostate bed and pelvic lymph nodes, may not even get it if it has already migrated somewhere else.
Not trying to raise alarm, but PCa can travel pretty far from its original home; I saw a case where it traveled to the clavicle and that person was basically put on ADT for life. However, he was still alive 14 yrs later.