I underwent nerve sparing robotic surgical removal of my prostate at Duke U Hospital in 2007 and some PSA showed up about 15 dos later, 0.1. My biopsy showed a Gleason 6 by Duke's account and a Gleason 7 by UNC's. My tumor was in a bad spot, right up on my urethra. Post surgical report showed clear lymph nodes but an irritated prostate bed, probably due to prolonged infection re the surgeon. PSA rose very slowly but steadily until it showed a somewhat abrupt jump to .34 in 2012. I was living in Phoenix at the time so I had a consult with the radiation oncologist at Mayo AZ. Memory fails me as to how many treatments I had, 35 sounds right, at 68 Gy I believe. They just did the prostate bed due to by Gleason score, PSA history, and a clear some scan. No near term side effects other than some mild skin irritation. I was lucky in that the surgeon I had at Duke was highly competent and I never had any serious urinary retention issues. Radiation didn't cause any either. Post radiation my PSA augured down to 0.1 and stayed there until this January.

>My msg got truncated 🙁 will add later

This last January I suddenly developed a late radiation side effect, hemorrhagic cystitis, and it lasted about 2 months at various intensities. As part of the workup for it I was given a sensitive PSA which came back at 0.03. So, I'm now being followed every 6 months since Mayo doesn't do sensitive PSA's and doesn't consider it a recurrence until it hits around 0.2 or rises steeply. Per the radiation oncologist I had a higher likelihood of incurring side effects than the usual patient since I have a connective tissue disorder.

Here is something about combining salvage radiation with ADT but I'm not sure if that's what you're intending to do. Maybe you are looking at radiation, outcome evaluation, ADT if needed.
https://prostatecancerinfolink.net/2015/06/03/combining-adt-and-salvage-radiation-therapy-mproves-outcomes/
There are some major breakthroughs in imaging having an impact on the diagnosis and treatment of recurrent prostate cancer. Just something to have on your radar.
http://www.mayoclinic.org/medical-professionals/clinical-updates/general-medical/novel-treatments-for-recurrent-prostate-cancer
So I take it that your bone scan was clear as well as any other images?

There are some sites out there where many patients in your position share experiences, such as https://prostatecancerinfolink.net. I hesitate to recommend
one since I haven't gone through ADT. I do have hypogonadism, low testosterone but not zero, probably as a consequence of autoimmunity, or just aging. It does impact multiple domains, no question.

So what have your doctors advised as immediate next steps?