I had a 2.9cm AN radiated (GK) last September at age 31. I had about 5 consultations with a variety of specialists prior to making what at the time was an incredibly tough decision. Like everybody, I heard a range of opinions depending on who I asked. ENT's who assisted with surgery and had no radiation background flat out said I could not have radiation. Well known surgeons (including one at House) said I could do both, but recommended surgery due to my young age and cited a lack of 30-40 year radiation outcome data as a reason. However, surgeons noted that malignancy was probably very unlikely long term and even if it occurred, I'd likely survive. Radiation specialists (Dr. Chang @ Stanford and Dr. Lunsford @ UPMC) said lifetime likelihood of malignancy was 1 in 1,000 to 1 in 10,000 or even 1 in 20,000. Chang and Lunsford said long-long term data don't exist in part because malignancy is so incredibly rare studying it is not scientifically feasible.
Bottom line- there's no free lunch. I still feel great and at peace about my decision- mostly because I did so much research, including talking to both surgeons and radiation docs, and took as much time as I needed to decide. I strongly recommend sending your stuff to pro-surgery and pro-radiation docs and asking them your burning questions. Otherwise you just get one side of the story.
Adam