Rising or persistent PSA following RP:
W/o evidence of definitive lesions or locations by PSMA Pet scan, the prostate bed and pelvic lymph nodes are the suspected location for residual PCa.
Radiation Treatment, either IMRT or proton, to the entire prostate region together with (and more recently possibly w/o) a short or long course of ADT is the researched treatment (see SPPORT trial).
In 2023, I and 2 friends each had Salvage Radiation w/ 4 - 6 mos ADT for BCR or persistent PSA following RP from 3 different ROs at Johns Hopkins Baltimore and Sibley Memorial Wash DC Hospitals.
All 3 of us have had undetectable PSA since treatment.
And, of course, we are grateful for the current results and hopeful that they continue.
Note: Layman summary.
Best wishes.