Nonfunctional adrenal tumors typically do not require treatment. The goals of treating functional tumors of one or both adrenal glands are to destroy or remove the affected glands if possible, and remove or destroy any sites where malignant tissue has spread. Other goals are to relieve the discomfort suffered by the dog and to restore and prolong its quality of life.
The preferred treatment for dogs with functional adrenal gland tumors is to remove them surgically. X-rays and ultrasound examinations can show the precise location of the adrenal mass and can also reveal generalized enlargement of the adrenals or masses in other areas. Without surgery, there is no way to determine unequivocally whether an adrenal gland tumor is or is not malignant. Because the adrenal glands in dogs are so tiny, surgical removal of an adrenal mass requires removal of the entire affected gland. If surgery is hoped cure the dog’s hyperadrenocorticism, appropriate margins of healthy tissue surrounding the affected adrenal gland must also be removed.
Dogs with adrenal tumors will need to be stabilized medically in a veterinary hospital before they can be taken safely to surgery. Pre-surgical management will include administration of medication to inhibit the production and secretion of adrenal corticosteroids while the surgical procedure is taking place. Most dogs will need intravenous fluid support to keep them well-hydrated during and after the surgery. Other medical therapy may be necessary to reduce hypertension (high blood pressure), if it is present in the particular patient.
Medical management and supportive care are extremely important for dogs with adrenal gland tumors, whether or not surgical removal is attempted or entirely effective. If both adrenal glands are removed, or if only one is removed but the contralateral gland has atrophied to the point of being nonfunctional, the dog will have to be on oral corticosteroid replacement therapy for the rest of its life. Long-term steroid treatment can be as costly as, or even more expensive than, the cost of the surgery.
A dog with a functional adenoma or adenocarcinoma that has not spread to other parts of its body, and that recovers well following successful surgical removal of the affected glands, usually has a fairly good prognosis, as long as its owner follows the veterinarian’s steroid replacement therapy instructions to a tee. The average survival time for dogs in that circumstance is somewhere between 16 to 36 months following diagnosis and surgery. Unfortunately, malignant masses that have metastasized or become locally invasive carry a guarded to poor prognosis.
Surgical removal of the tiny adrenal glands is called an “adrenalectomy.” This is not a simple procedure, but it is done successfully with some frequency in veterinary medicine. Relatively non-invasive laparoscopic adrenalectomies are occasionally and increasingly being performed.