We must be brothers. I too am 68 with Gleason 9 (local), Radical Prostatectomy, and 35 radiation treatments. I started Eligard just before radiation. I did Eligard for 18 months. My new onocologist recommends 6 months of Eligard rather than the historical 18 -24 months of Eligard. This protocol is possible with the release new PSMA scans.
So after the 6 months you monitor your PSA and testoserone every 2 months. Should you see your PSA increasing, then your onocologist runs a PSMA scan which shows any prostate cancer in your body and its location. The doctor can then target the cancer with radiation or surgery. The big advantage with this approach is that the hormone treatment is limited to 6 months. This limits the amount of nasty side effects of hormone treatments. The longer you do hormone treatment the less likely your testosterone will rebound. Good luck my brother and may your cure be in sight.