I went on Pituitary Deprivation Therapy 2 weeks after my RP when my first blood test for PSA came back at .2.
First Firmagon for 3 months, then Lupron for a year, then Eligard for a bit more than a year. In total, my testosterone was no higher than 2.2 ng/dL and my PSA < 0.03 for more than 3 years.
3 months after the RP and starting hormonal therapy I got ~80 Gy over 2 months at 5 sessions a week.
Now it is almost 4 years since the RP. My testosterone has screamed back up to a whopping 204 ng/dL and my PSA is back up to 0.08. Looks like that stuff didn't work and I will most likely go back on intermittent Eligard for the duration.
Best of luck to you.