Wanda

At least in my case, the decision to do chemo & radiation was because the alternative surgery would have such a negative effect on my quality of life. The cancer came back anyway and my medical team was unfortunately 100% correct on surgery damaging my neck, shoulder, and ability to swallow. As my ENT put it: "we tried to spare you the ordeal of surgery"
Your point however about chemo & radiation being deemed essential to deter recurrence seems valid enough to me, since when the pathology report post surgery came back, they said that without even more radiation and different chemo, my cancer would more probably than not come back a third time.