I have advocated keeping all the teeth you are able to.  Eating problems are made worse by having no teeth.  Joanna has given good advice; seek dental advice from someone very familiar with radiation and don't let them take teeth without very good reason!  
I still have every one of my teeth including wisdom teeth (of course you know why    

  )
I think it is good they are looking at a possible tonsillectomy as well.  My tonsil cancer was not visable during the usual visual exam, even though it had spread to 3 nodes.  
I pray for your speedy recovery!