@stew80
These are good questions to asked your R/Os and urologist.

I can pass on to your my experience. When you say 5 rounds it means high dose radiation and thus lessor rounds of radiation. When you say 28 it would indicate low dose extended treatment radiation.

Now what are difference in success? My R/Os said they are about equal. Then why not all just do the 5? My R/Os, and my PCP answered my question when I asked the same one you did. All stated that their research was showing more side affects and degree of side affects from the high dose radiation.

Some posters will have minimual side affects and others will have substantial. I had the low dose 30 rounds and had miminal side affects. I had my radiation done at UFHPTI which does proton radiation. The difference between proton and photo is that proton enters body at a lower dose, releases it full dose at the determined spot, and stops. It does not exit the body like photon does.

Now both have the same success rates. The theory behind proton would be less damage to surrounding tissues and organs. It is why I chose UFHPTI versus only have photon if done a Mayo Jacksonville (building new cancer center that will have proton radiation and opens in 2026).

Stew, 5 rounds is SBRT - Cyberknife, MRIdian….high doses directly to the prostate.
25-39 rounds is usually EBRT - lower doses delivered over a longer period of time to a wider area, usually the prostate and the pelvic nodes.
There are very specific uses for each depending on the nature of your cancer.