I had a prostatectomy in February 2022 followed by salvage radiotherapy six months later. My PSA became undetectable (<0.01) shortly afterwards and remained that way until December last year. I was a bit shocked to get a PSA reading of 0.02. Three months later it was 0.01 and last week it returned to undetectable. All of the tests were done at the same hospital. I saw my Oncologist shortly after the first positive reading in December. He suggested it might be BCR but too early to tell or it might be a small remnant of my prostate has woken up after the radiation and is producing PSA. Now with my recent undetectable reading those two theories appear to have been eliminated. I was just wondering if anyone has experienced an unexplained PSA blip or got any other theories. There is another factor that may or may not be relevant. Back in October last year I started to be weaned off an immune suppressant drug (Mycophenolate) which I was taking for an autoimmune disease. I took my last dose of the drug (which depletes the body’s B cells) back in December and so far, (happy days) my autoimmune disease has stayed in remission. Could it be that this boost to my immune system has also killed the PCa cells?