Hello, this type of surgery is preformed far more frequently than the pituitary gland surgery so the results are much higher. This type of surgery should yield good results as long as the tumor has not spread to the lungs. The problem with this type of tumor is that they do have a tendency to spread to the lungs and once this has happened there is little hope for a recovery and I would not recommend surgery at all as I think it would be a waste of precious time you could spend with your baby. I would suggest having an x-ray done prior to deciding whether surgery is an option or not. I would x-ray the chest to make sure that the cancer has not spread to the lungs. If it has I would not do surgery but opt for chemical treatments to try and prolong the life of your baby. If there is no spread to the lungs then I would go ahead with the surgery. I am sending a few links to you about the disease and the most common forms of treatments for you to look at. If you need anything else be sure to let me know.
http://dogs.lovetoknow.com/wiki/Cushings_Disease_in_Dogs
http://www.kateconnick.com/library/cushingsdisease.html
Veterinary Assistant
10 years breeding, 6 years in Veterinary medicine, Lifetime of Dog ownership