Brain Tumors in Dogs Prognosis

Brain tumors in dogs occur due to abnormal cell growth. Canine brain tumors may be primary, meaning they originated in the brain itself, or secondary, meaning they have spread to the brain from another part of the body. Brain tumors are relatively common in dogs. Here's what you should know.

Causes and Symptoms of Canine Brain Tumors

Vets don't know what causes brain tumors in dogs. Dog brain tumors may occur due to environmental, genetic or other factors. Your dog's risk of developing a brain tumor increases after he reaches five years of age.

Certain breeds are more prone to developing brain tumors than others. Dolichocephalic breeds, such as border collies, which have long, narrow snouts, are more prone to brain tumors that begin in the membranes surrounding the brain. Brachycephalic breeds—those with short, pushed-in snouts—are more susceptible to pituitary tumors.

If your dog has a brain tumor, his most obvious symptom will likely be seizures. Other symptoms could vary, depending on where the tumor is located. If your dog has a tumor in his forebrain, he could seem disoriented, confusion, and less aware of his surroundings. He may seem depressed and lethargic; he could also experience an increase in thirst.

If your dog has a cerebral tumor, he could exhibit any of the following symptoms:

  • Lack of motor control leading to a wobbly, swaying gait
  • Tilting of the head
  • Lowered appetite
  • Vomiting

If your dog has a tumor in the brain stem, he could develop some or all of these symptoms:

  • Loss of equilibrium
  • Paralysis of facial muscles
  • Trouble swallowing
  • Difficult eye movement
  • Weakness affecting only one side of the body

In addition to these physical symptoms, your dog could also display changes in behavior and mental function. Your dog could begin to forget the things he has learned, and may seem unable to think clearly or learn new things. Your dog could become depressed, irritable or aggressive, no matter how happy or mild-mannered he was before. Your dog may become over-sensitive to being touched; he may perform compulsive movements; he may begin pushing against hard surfaces with his head, as a reaction to the pressure that the tumor's growth is causing on the inside of his head.

Diagnosing and Treating Dog Brain Tumors

Your vet will need a complete medical history and a physical exam to diagnose a brain tumor. Ultrasounds, X-rays and MRIs can determine if your dog's tumor is secondary or primary. A tissue biopsy can confirm that the tumor is cancerous. 

A combination of surgery, chemotherapy and radiation treatment are used to treat brain tumors in dogs. Surgery can remove part or all of the tumor. Radiation and chemotherapy can slow or stop the growth of cancerous cells. Your vet may prescribe other medications to treat your dog's brain tumor symptoms.

Prognosis for Dogs with Brain Tumors

The prognosis for dogs with brain tumors is often poor. Without treatment, most dogs survive for about six months after diagnosis. Treatment can help your dog survive for as long as 16 months after diagnosis.