Regarding the choice of proton therapy:

I was surprised when I first asked my Radiation Oncologist (RO) about proton therapy for my "at least high risk" prostate cancer. This guy was a senior oncologist at an NCI designated cancer center in a big city. You can't listen to a sportscast in that city without being inundated with ads promoting the fantastic proton treatment for prostate cancer that this center offers. The RO explained that the prostate cancer department in that center does not believe protons are in any way superior to photons. They think the ads are misleading.

Recently I heard an interview of Dr. Brian Davis, radiation oncologist at Mayo Clinic Rochester, recorded at the 2025 SouthWest Prostate Cancer Symposium. The Mayo Clinic there is putting in a second proton facility, so they must like what it can do. He started out his talk saying they had a large donation that helped them build the facility, to say they don't have to worry about treating everything in sight to justify a huge investment.

Are protons better than photons, for prostate cancer in particular? It's a "wash", he says. Protons are clearly superior for some types of cancer.
https://grandroundsinurology.com/proton-therapy-for-prostate-cancer/