PatsyJo,
Welcome to the neighborhood. Sorry you had to find us but I am glad you are gathering as much information as you can in preparation of perhaps the battle of your (and your husband's) life. I am a little curious how you picked the place you are going. In case you don't know, UT Southwestern is in the final stages of their certification process to become a National Comprehensive Cancer Network member. They are also part of the University of Texas system like MD Anderson.
I am not sure why the team would recommend radiation without chemo but as Gary suggests, I would use every weapon in the arsenal to beat the beast the first time around. In my case, I had some molars pulled when I was young and I did not spend the money for bridework earlier and because of the angle of the other molars, they strongly suggested removing all of my remaining molars to prevent issues at areas that I could not effectively brush or floss. Without the radiation, I probably could have made it many more years but the fear is that once infection sets in (after radiation), it could be life-threatening. Ironically, the insurance company refused to pay for the extractions done while I was getting a mediport and PEG tube placed. After almost two years of battling with them, they have finally paid but then they refused any implants. Their words were to the effect the only reconstruction covered would be breast prostheses since the law required it. I couldn't find any use for that...or at least didn't see how it would help me eat better

so I opted out.
What your husband is going through right now is pretty much the course that I took. It is a devastating diagnosis and the more you learn about the treatment, the more scared you become. Many have traveled the road ahead of him and any of us will help both of you in any way possible!
I had just completed my Hep C treatment when a lump popped up in my neck and after 7 months of doctor rounds, I found out it was cancer that had already spread to two lymph nodes. The first thoughts that came to my mind was related to the rough Hep C treatment and what a waste that had been. I had a little anxiety that the Hep C would return as it is a virus and the body was going through massive stress during radiation and chemo. However, 18 months post-treatment I have had almost monthly blood work and the virus appears to have been kept in check. My liver enzymes elevated a couple of times and one even slipped below normal which mystified the medical team.
If there is anything I can do or if you have any questions please let me know. I am wishing you nothing but the best as your plan evolves.
Ed