Canine brain tumors aren't uncommon, especially in older dogs. The sizes, types and degrees of cancer vary widely, which affect how they're diagnosed and treated. As veterinary specialists learn more about the subtleties of brain cancer, they're able to use this information to help improve the quality of life for dogs afflicted with this disease.
-
Types
-
Meningiomas are the most common types of brain tumors found in dogs. They grow on the membranes of the brain lining rather in the cells of the brain, but they're categorized as brain tumors because they can grow into the cranial cavity and compress brain matter. These types of tumors are more common in long-nosed breeds, such as the golden retriever. Gliomas are tumors that grow in brain cells. They're more common in short-nosed dog breeds such as the boxer, the bulldog and the Boston terrier.
Symptoms
-
Since brain tumors sometimes compress nerves, many symptoms will affect the nervous system. You may observe a change in your dog's gait or sense of balance. Your dog may walk in circles or lean to one side. He may undergo personality changes, such as becoming aggressive, or he may have seizures. You may also notice facial paralysis and, in some cases, blindness.
Diagnosis
-
Since brain tumors occur in brain tissue, they're not usually detectable on radiographs, or X-rays, of a dog's skull. When symptoms of a brain tumor are present, an MRI or CT scan can help identify the location and size of it. These tests can also help determine whether or not the tumor is operable. Sometimes a mass discovered on or in the brain isn't a tumor, but something else, such as an abscess, so it's important to have a biopsy performed to determine whether or not it's cancerous.
Surgical Treatment
-
Depending on the type and location of the tumor, it may be surgically removed. Surgery may be chosen if there's a good chance the tumor can be removed completely, which isn't common. It's also performed to reduce pressure in the cranial cavity, and hopefully relieve some of the symptoms caused by the tumor. According to the North Carolina State University College of Veterinary Medicine, tumors that are situated on the surface of the brain, near the front of the cranium, have the best chance of being successfully removed.
Radiation
-
Radiation is another method of treating canine brain tumors. Ionizing waves of energy, such as X-rays or gamma rays, are directed toward the tumor to kill the cancer cells. Dogs are given a general anesthetic prior to each session. Radiation is given in small doses, which help minimize side effects. The hair in the area being treated may become lighter, or the tissues in the region may become irritated.
Chemotherapy
-
Many chemotherapy drugs can't cross the blood-brain barrier, and thus are ineffective against brain cancer. However, there are a few drugs, including temozolomide, that will cross this barrier and effectively treat brain cancer, particularly gliomas, which are buried in brain tissue and more difficult to remove. Some dogs experience few to no side effects, while other dogs may experience vomiting and diarrhea.
Prognosis
-
It's difficult to predict how a dog with a brain tumor will tolerate treatment. Depending on the size of the tumor and the severity of the symptoms, the prognosis for a good quality of life can range from a month to a year or more. In general, dogs who receive radiation for brain tumors generally live about a year from the time radiation therapy started. Early and thorough medical treatment can help give your dog the best chance of survival.
-