Adrenal Gland Cancer, also known as Pheochromocytoma, involves the presence of a tumour in the adrenal gland. This tumour affects the glands by causing them to make an excess of particular hormones. Other ways the tumour can affect the animal is to cause an increase in blood pressure, heart rate, and even the breathing rate. These symptoms come and go due to the fact that the hormones are made in different amounts at different times. The tumour is known to metastasize quickly to other regions in the dog thanks to the fact that the endocrine gland is affected, which works to spread hormones throughout the body. Usually pheochromocytomas will move to organs that are found near them.
Most professionals agree that there doesn’t seem to be a known cause for Adrenal Gland Cancer and it is labeled as idiopathic (meaning it has an unknown cause).
Because no one really knows what causes Adrenal Gland Cancer, there is no way to prevent it.
Symptoms are often intermittent. It’s also important to note that sometimes no symptoms are present at all. Some of the common symptoms may include the following:
- lack of appetite;
- depression or little interest in usual activities;
- increased urination;
- rapid breathing;
- increased thirst;
- weight loss; and
- bloated abdomen.
Dogs at Risk
This type of disease is often found in older and middle-aged dogs. As well, large-to-giant breeds and females seem to be at higher risk. In particular, German Shepherds, Dachshunds, Labrador Retrievers, some breeds in the Terrier Group, and Poodles are known to be predisposed to the condition.
Testing and Diagnosis
The first step in diagnosing the animal is to conduct a complete medical history of the dog’s health, behaviour, and the details of the onset of the symptoms. Sometimes a rapid heart rate will be discovered during the exam. The veterinarian will look to determine if there is a mass in the dog’s belly region or if there is an increase in fluid. In some cases, nothing will show up in the physical examination. The next step is to conduct blood work to look at the biochemical profile and the blood count. A urinalysis will also be necessary. These results will give an idea of how well the dog’s internal organs are functioning and if an infection is present. Blood pressure will also be taken and if it is high, it will point towards hypertension. Another test the veterinarian may order is a blood test meant to look at how well the adrenal gland is functioning.
When testing the dog’s heart rate, if it is found to be abnormally high or has an abnormal rhythm, an electrocardiogram (ECG) may be the next step.
Ultrasounds and x-rays are used to look at the dog’s chest and abdominal regions. Often abnormalities will show up on the ultrasound image or on the x-ray.
In some instances further tests may still be needed such as a magnetic resonance image (MRI) or even a computed tomography (CT). These tests are much more sensitive and will be able to give a complete picture of the internal organs.
For a final confirmation the veterinarian will take a biopsy of the adrenal gland and send it off for laboratory analysis.
Treatment and Prognosis
For most dogs the best method of treatment is surgery. If the dog was found to have a high heart rate or high blood pressure, medications will be prescribed before surgery so the dog’s levels return to normal. Sometimes the animal will need to be on the medications for several weeks before it is well enough to undergo surgery.
The surgery involves removing the affected adrenal gland. This is a delicate operation, as the adrenal gland is located near some large blood vessels. During surgery it may be determined that other organs are also being affected. If this is the case those organs will need to also be removed either entirely or in part.
Once surgery is complete you can expect the dog to remain in the intensive care unit of the hospital until it is stable. It is common to run into problems after and during the surgery, so careful monitoring is needed. The veterinarian will be monitor the dog’s blood pressure, wound site, heart rhythm, and breathing. Recovery can be hard for some dogs and they may not make it through.
After the tumour has been successfully removed and the dog has spent time recovering, it can return home. The dog may need a while to get back to its old level of activity. If the dog has no other medical problems, it can often live three years or more after the surgery is performed.