Ask what the Proton treatment plan is. Most salvage radiation is to the prostate bed and that can be treated with the initial radiation but falls outside what is removed with RP. Salvage treatment if distal recurrence will be the same as with RP: Systematic treatment with ADT, Chemo, etc. If confined to the prostate than whole gland Cyro or HIFU is usually used. Salvage RP is very unusual due to scar tissue left by the radiation. At your age most patients are strongly encouraged and chose RP over radiation. If it looks like it might not be contained in the prostate EPE, etc. than you might have salvage radiation within a year or 2 of RP. That would be a reason to choose radiation over RP. Likely to have more side effects from ADT than radiation but if short 4-6 months at your age should recover fully. If you go for ADT get the pill (Orgovyx) vs. a Lupron shot. Once you are jabbed, you are stuck in more ways than one.