In what situation, if any, should a proton boost be used to boost gross disease in head and neck cases?

Good question. It reminds me of when IMRT was newer, and our practice at UCLA was to give 5 weeks of 3D conformal radiation to whole pelvis, reserving IMRT for the prostate boost portion.@Dr. First Last and I looked at the outcomes, and they didn't seem much different, toxicity-wise, than those who got 3D conformal alone for the whole course. To me, this meant that to meaningfully reduce toxicity, the whole course probably should have been done with IMRT (unpublished data).

If there is a challen...