Thank you for sharing that. That's my concern about too tight a focus with radiation. Current imaging can't see isolated cancer cells, so if your radiation therapy is so focused that it hits only the cancer they can see, what about the cancer they can't?

It must be a very difficult decision. I'm guessing (as a layperson) that they take things into account like Gleason score, speed of growth, PSA, number of sites, etc before deciding on recommending photon vs proton and tight vs loose focus for radiation. There's probably no "right" answer, just a complex balancing act between risks and side-effects. I'm so sorry that it didn't work out for you.

There's also a tendency to over-apply new technology -- it's a very human response. The Gartner Group has a "Hype cycle" curve showing how new things (like generative AI) initially get overused, then there's a backlash, then they settle in somewhere in the middle where they're genuinely useful (but not the answer to everything). I'm sure that applies to new medical breakthroughs as well, though at least they tend to be tempered by formal studies and peer review.