@dmedlen
Did your buddy have photon radiation? Must admit that is an extreme case. I’ve heard from many people that have had SBRT and IMRT and There’s a wide range of results from no problems at all to a small percentage that have this extreme issue like you describe.

As for proton 15 years ago, that’s really not significant when you look at the history of it.

If you watch the 2023 PCRI Video and see Dr. Carl Rossi talking about radiation you find some interesting things. For one he’s been doing Proton radiation treatments since 1994 when they built a building for the machine in San Diego. The first patient was the person that invented it, He lived to over 100. He has done Proton radiation on over 13,000 prostate cancer patients.
That video link is Starting at 3:38:45