A brain tumor can be the most difficult type of tumor to diagnose in a dog. Most veterinarian facilities do not have access to magnetic resonance imaging machines that enable the visualization of a brain tumor. The skull of the dog blocks X-ray images making it difficult to see the brain and any tumor inside the cranial area.
According to VetInfo.com, the symptoms of a brain tumor vary for the location of the tumor. If the tumor is located in the forebrain region, the symptoms include seizures, loss of learned behaviors or memory, disorientation, confusion, depression, excessive thirst and loss of awareness. The symptoms for a tumor located in the brainstem include weakness on one side of the body, loss of balance, facial paralysis and difficulty swallowing. Tumors located cerebellum may cause head tremors or localized seizures, wobbly walking, head tilting, vomiting and a loss of appetite. All tumors may be associated with a sudden shift of personality or behaviors including irritation, sensitivity to touch, pressing of the head into objects and aggression.
Diagnosis of a brain tumor in a dog is typically based on the elimination of other conditions through evaluation of symptoms and blood work. A veterinarian may check the dog for other signs of cancer in the body, but this does not necessarily mean that the dog has a brain tumor. Only through the use of an MRI can a positive diagnosis of a brain tumor be ascertained. Many dogs with such tumors go undiagnosed due to the lack of sophisticated diagnostic and imaging equipment. If a mass is seen during a MRI or CT scan, a biopsy will be required to determine if the mass is cancer and not an infection pocket.
If a brain tumor has been located in the dog, treatment depends upon the size of the tumor, the location and the potential malignancy of the cancer. The most common treatments include removal of the tumor through surgery, if possible, followed by radiation and chemotherapy. Most dogs are never treated for the tumor though and are given medications to ease symptoms rather than stop the tumor due to the inability to fully diagnose the brain tumor.
The prognosis of dogs with brain tumors varies widely. The general guidelines provide by the North Carolina State University College of Veterinary Medicine state that the worse the symptoms appear, the worse the prognosis. In addition, the larger the tumor, the worse the prognosis and the more terminal the condition is considered. Tumors of the forebrain are less serious than tumors of the cerebellum and the brainstem and therefore carry a better prognosis. Radiation can prolong and improve a dog's quality of life but not necessarily halt or destroy the cancer.
According to CanineCancer.com, the exact causes of brain tumors in dogs is unclear. Boxers and Boston terriers are more prone to the condition. Other causes of brain tumors include radiation exposure, head trauma and pesticides and other toxic chemicals. A healthy diet and exercise help prevent cancer in dogs.