Glad and sad to welcome you to our forum!
Read all the info on this forum and website before you make a decision. The ANA recommends that you get evaluation and treatment from doctors who have significant experience with this disorder. This recommendation is accurate, in my experience. The only thing I would have done differently, in my case, is to have followed this advice. I had treatment locally, and I like my doctors. However, as side effects/symptoms crop up, I've had difficulty finding anyone to help, who has good experience with ANs. In the case of radiation treatment, you can wind up getting your AN zapped by people who are right on target, but who have little experience dealing with the aftermath.
Your tumor is comparatively small, and these grow slowly. So take a deep breath, try to relax, and make a good, informed treatment decision.