Hi Laura,
My husband is just finishing up his 40 radiation treatments. Although he didn't have the mouth sores or pain associated with the radiation he did need the feeding tube by the 4th week. Believe me, to this day he wonders how anyone could do this treatment without one. As a caregiver, it makes life alot easier. As my husband lost interest in food at least I was able to give him the nourishment he needed through the tube. Also, juicing a ton of vegetables kept him regular. I would highly advise getting one just in case. The last thing you need are complications from dehydration or malnutrition.
Take care.
Wendy