Mast cell tumor and my 9 year old American Bulldog -- advice please!!!?

Hi -- My 9 year old American Bulldog was just diagnosed with having a tumor with mast cells on her leg. It has been there for over a year and was diagnosed earlier as just a fatty tumor. Over the past year it has gotten bigger so the vet aspirated it and decided that she needs surgery to remove it immediately. It will then be tested to see how much the mast cells have spread, etc. The main question I have is about the surgery -- as she is an older dog and also a breed that has some risks ociated with it, I am afraid of the anesthesia despite the fact that my vet is confident that she will come out of it okay. She is not experiencing any other symptoms, and has no other problematic health conditions that would complicate things. Any advice on this or success with holistic remedies for mast cell tumors would be GREATLY appreciated -- thank you!!!