First time around, right after RARP I got 2 & 1/2 years of leuprolide chemo. 3 months after surgery I got 40 radiation treatments to prostate bed and surround. Side effects from those were not fun. 8 years later, I just finished another 30 hits of salvage radiation to my pelvic lymph nodes and spot treatment of 3 metastatic pelvic lymph nodes. I am also 16 months into another round of leuprolide + enzalutamide chemo. Uro and MO said they wanted me to stay on that chemical regimen until it failed, RO said 24 months then done. The whole point of getting more radiation was to try and kill the cancer and to get off the chems again, which I will do next Jan. Another vacation from chemo if nothing else and I am prepared to play radiation whack-a-mole with any more mets that show up to further kick the can down the road.
My take on this is that there is physiologic and psychological value in "de-bulking" the primary tumor. That is where the cancer started and where it is most developed. If nothing else that slows its progress and gives the satisfaction of knowing that most - if not all - of it has been removed and discarded. The leuprolide and radiation further slow it down if they don't kill it off outright.
While the side effects have not been pleasant, they have not been intolerable and there is a lot to be said in favor of being alive to complain about
them.