Here is my take, If you have to get rads, I would get the chemo. Chemo sucks but it has shown to help. Curing first time is most important. I am un aware of any serious long term down sides to chemo, so you are trading, short term pain and suffering for less chance of reoccurance.
HPV or non
HPV this is still a deadly disease. Now if you don't need rads, that's a different situation. Rads always have long term QOL issues.
Remember, it is always YOUR choice, Doc's just administer the treatment. If you don't agree with them, go somewhere else!