I was at a meeting recently and have been asking exactly this question. There is no research data on its use in this preventive way; while the theory seems to support giving it to everyone with H & N cancer, randomised clinical trials would be needed to see if it really works. These are early days yet, and there can be troublesome side effects (if you bother to read the small print). Interestingly, when forced to say if they might use it for themselves if they had H&N SCC, several oncologists say they would! It is the first of several new drugs on the way and not all is clear, so the scientific community has to move cautiously as there are cost implications.