The fact that your PSA isn’t rising is a good thing, Regular prostate cancer is apparently not growing and spreading.

The problem is that after a long time, the prostate cancer can change and become neuroendocrine prostate cancer. That cancer doesn’t produce PSA, which could be why your PSA isn’t rising. Neuroendocrine prostate cancer does not produce PSMA so it can’t be found on the scan. You need to do an FDG PET scan to find it since it consumes glucose which regular prostate cancer does not do.

It could just be that your cancer isn’t active anymore, Or is growing so slowly that it can’t be seen in the scan.

I had a prostatectomy in 2010 and salvage radiation in 2014. After all these years, I worry about having it change to neuroendocrine.

Lots of options to talk to your doctor about.