David

Your impression is exactly the one I had from my research when this popped up on the forum. I did raise it with my RO with the caveats that I knew it was only proven with brain & pediatric cancer but seemed promising for head & neck also. I was stunned by his answer - even though he cautioned that he did not want to sound cynical nor be critical of the new IMPT centers. He had already referred several of his patients who were all rejected by more than one IMPT center since they had already had IMRT & Cyberknife. He said it was understandable that since IMPT is still seeking empirical validation for non brain cancer and non pediatric patients, that except for those two categories, patients who had radiation twice were not being accepted because it was more likely than not to have failures which would not necessarily be the fault of IMPT yet statistically they would.
He emphasized what has been the story on this forum and several patients experience, re-radiation after the "maximum' is risky. He does it a lot, in part because of referrals from other hospitals, doctors and even other CCC. If he had an IMPT machine, he'd try it but he can understand since they are so scarce why they are being used on those whom they can help the most.
Charm