Anastrozole is endocrine therapy, to prevent hormones from feeding your cancer.
If I were concerned about the radiation, I would talk to my radiation oncologist about this, but I can tell you radiation has come a long way in a short time. They can truly pinpoint a small area now, the risk of lung or bone damage is much less than years past. Also being on the right works in your favor.
Will you come back and tell me what you decide after seeing the doctor?