@beluga
Hello @beluga: Not sure who you were replying to or someone else. Here is information given to me about photon and proton radiation treatments. This comes from my R/Os at UHPTI and Mayo Jacksonville. The same secondary damage to organs and tissues happens with both photon and proton radiation treatments. Proton is considered possible lower secondary damage and secondary cancers due to highly controlled beam.

Proton radiation does not proceed past programmed spot where photon does. The R/Os I mentioned say the success rate of both are same but it is the fact that proton can be stopped prior to exiting the body where photon cannot.

Many have Space/Oar (I did) and or balloon to move colon away from prostate to lesson secondary damage to colon. However since most, like me, margins need to be treated so the chance of a certain amount of radiation can affect surrounding organs, and tissues.

It is why UFHPTI gives an information packed and spends hours with you going over not only the treatments but side affects and what is common and what causes it.