Hi!
I had LDR Brachy mid 2023 and since then have had fluctuating PSA which up to now has been attributed to the 'PSA Bounce' phenomenon which occurs in more than 30% of patients who undergo radiotherapeutic treatment. I've posted about it quite a lot in the threads you can see on my profile and there's a couple of other guys on here post Brachy who seem to be also be experiencing bounce at the moment.
Bounce isn't limited to LDR BT though, it can happen after any radiation treatment and with or without HT. Lots of info out there if you google 'PSA Bounce after radiation treatment for prostate cancer'.
I'm struggling a bit with your timeline re when you had the radiation but whilst bounce usually occurs within 36 months of having treatment, it can go beyond that occasionally. I'm also unsure how HT might alter that timeframe but as said, having HT itself doesn't mean you can't experience bounce.
At this stage, having had the biopsy hopefully confirm the PSMA PET was a false positive, and no other tracer uptake seen anywhere else, I'd hope that the increase is a temporary benign bounce and it will fall again, or your natural PSA level is still settling after coming off HT.
So, easier said than done but I'd try and be relaxed about it - can't do much more than have the PSMA PET and a biopsy comeback clear and if the explanation for the PSMA false positive is that there's still radiation at work in the prostate then a bounce explanation is very feasible.
If you still haven't seen the surgeon, worth talking to him about possible bounce although I think an onco would be more knowledgeable about it, especially in combination with HT.