Proton Beam Radiation - Is it worth it?

The cost of Proton Beam radiation is twice as much as regular radiation (IMRT). And yet there has never been a study that definatively  compares the two procedures. 

This is typical of procedures for prostate cancer. There has never been a study comparing conventional interventions. 

Meanwhile the cost of treatments is continually on the rise.

Will the Medicare system be able to afford cancer treatments that are now in many

cases in excess of 6 figures. 

Cancer treatments are becoming more and more expensive. If success rates and reduced side effects are the result then the cost can be justified. We wonder if this the case.

What do you think?

Picture - PAF hikers at Sugarloaf State Park - Sonoma County, CA