Paul and others are better educated and experienced to go into the details of Proton Therapy. I know for a fact the facilities and equipment are very expensive and there are still very few of them built. My understanding is it has the ability to better focus and treat the cancerous tissues more precisely and able to do less damage to non cancerous tissue.

I mention it as your brother is so young and the more that can be done to reduce long term side effects is more important the younger the patient.

Talk to the RO about Proton and get their opinion if it might offer better outcomes for him. There are so many variables it is virtually to make any sort of generalized suggestion except for the doctors who have the full data and expertise.

Don