I was told by a doctor that the amount of Gys given during treatment was not really thoroughly scientifically tested or proven. They told me that 70gy or ~35 sessions with ~2gy/session was about the maximum limit the human head and neck area could take without serious complications. The fact that it is so hard to do any sort of clinical trial with dose deescalation, has made it impossible to test what the optimum level of radiation is. HPV+ scc's relatively high survival rate has made it possible for some clinical trials to be investigated on dose deescalation for the HPV+ subset of cancer patients. I was in one of those clinical trials.