By Dr. Becker
Adrenal gland cancer, also known as an adrenal medullary tumor or a pheochromocytoma, describes a malignant tumor of the adrenal gland that causes over-secretion of certain hormones, including cortisol, aldosterone, and epinephrine. These hormones interact with many other hormones and play a crucial role in the function of many organs in the body. Because this type of tumor affects an endocrine gland whose purpose is to produce hormones, pheochromocytomas often spread to nearby organs and can quickly metastasize to other locations in the body.
Fortunately, the disease is rare in both dogs and cats, representing 1 to 2 percent of all dog tumors and just .2 percent of all cat tumors. When it does occur, adrenal gland cancer is most common in older pets. The causes of adrenal gland cancer are not well understood, and this particular type of cancer is typically classified as idiopathic, meaning there isn’t a known direct cause.
Symptoms and Diagnosis of Adrenal Gland Cancer
Adrenal gland cancer can cause intermittent increases in heart rate, blood pressure, and breathing rate that coincide with surges in hormone production. Other symptoms that also tend to come and go, can include increased thirst and urination, panting, lack of appetite, weight loss, vomiting, diarrhea, bloated abdomen, pacing, shaking, weakness, lethargy, depression, seizures, and collapse.
If any of these symptoms occur in your pet, you’ll want to make an appointment with your veterinarian, who will take a thorough history of your pet’s behavior, health, and the onset of symptoms.
Your vet will check for a rapid heart rate and high blood pressure, and will palpate your pet’s abdomen to see if a mass or excessive fluid can be felt.
A complete blood count, biochemical profile, and urinalysis will be performed to check your pet’s organ function and determine if there’s any infection present. Your vet should also order a special blood test to measure your pet’s adrenal gland function.
Other tests that may be ordered include an electrocardiogram (ECG) or an ultrasound of your pet’s abdomen and chest, and potentially a computerized tomography scan (CT scan) or magnetic resonance imaging (MRI) to evaluate the adrenal glands more closely.
Treatment of Adrenal Gland Cancer
Pets with pheochromocytomas typically have more than one medical problem, and treatment should be approached according to which condition is most critical.
Traditional treatment of adrenal gland tumors involves surgical removal of the gland, or when surgery isn’t an option – for example, in the case of pets with inoperable tumors or those that are very ill or old – administration of drugs to treat the symptoms caused by the tumor.
When medical management is recommended, one of the drugs commonly suggested is Lysodren to manage symptoms. Unfortunately, Lysodren can also cause severe and life-threatening side effects, including extreme lethargy, loss of appetite, vomiting and diarrhea, collapse, and shock. Another drug called ketoconazole is also frequently used to manage symptoms, but it can cause liver side effects.
Adrenal gland surgery is very difficult, with many potential complications both during and after the procedure. Major complications arising from removal of adrenal gland tumors include severe spikes in blood pressure and pulmonary embolism. Other serious complications can include pancreatitis, hemorrhage, and electrolyte imbalances. After surgery, many pets receive steroid therapy until the remaining adrenal gland is capable of functioning normally. Some pets require supplementation for the rest of their lives.
Because the prognosis for this type of cancer is so grim, many pet owners opt for holistic therapy in place of surgery and drugs. Often an integrative approach -- involving significantly lower drug doses, combined with nutraceuticals to balance blood pressure and electrolytes, along with holistic cancer protocols – provides patients with an improved quality of life with no side effects.
The specific treatment protocol your pet receives will be based on her concurrent medical issues. Partnering with a holistic practitioner is important in finding the right protocol for your pet.