Do you have a dog that has been having seizures? Brain tumors in dogs can cause seizures, the most common clinical symptom. However, other symptoms such as a change in mentation and behavior, head tilt, circling, and ataxia may also occur. If your dog is experiencing any of these symptoms, it is important to take them to your veterinarian for an evaluation. Early diagnosis and treatment of brain tumors in dogs are essential for the best possible outcome. If you are concerned about brain tumors in dogs, please continue reading.
What are the different types of brain tumors in dogs?
There are two main types of brain tumors in dogs: primary and secondary. Primary brain tumors originate in the brain, whereas secondary brain tumors originate from a distant source of cancer metastasizing to the brain. Brain tumors can also be classified based on cell type and location within the brain.
The average age for all dogs with brain tumors was 9.5 years, according to a study. Both meningiomas and gliomas are associated with increasing age and body weight.
The most common types of brain tumors in dogs include:
Meningioma - Meningioma is the most common type of brain tumor found in dogs, accounting for 45-50% of all primary tumors, according to multiple studies. They often occur in larger dogs that weigh more than 15 kilograms (33 pounds), and these dogs are usually geriatric, or 12 to 14 years old. Golden retrievers, collies, and schnauzers are predisposed to meningiomas.
Glial tumors - Glial tumors in dogs are the second most common type of primary brain tumor, although they occur less often than meningiomas. In one study, they made up 20% of all primary brain tumors in dogs. Brachycephalic breeds such as boxers, Boston terriers, English bulldogs, and French bulldogs are predisposed to glial tumors.
Lymphoma - Lymphoma is the most common type of tumor that starts in the cells of the lymph system and invades the central nervous system.
Pituitary tumors - Some authors consider pituitary tumors to be primary neoplasms, while others view them as secondary intracranial neoplasms. In one study, pituitary tumors made up 25% of all secondary brain tumors in dogs.
Metastatic tumors - About 15% of all dogs with cancer have metastatic lesions. The most common type of metastatic tumor in dogs is hemangiosarcoma, which is a cancer that can spread to the brain. Most metastatic tumors are located in the cerebrum, and symptoms include changes in mental state or behavior. At the time of diagnosis, these tumors are often also located in other parts of the body.
What are the symptoms of brain tumors in dogs?
With primary brain tumors in dogs, seizures or changes in mentation are often the only clinical signs in dogs. With frontal and olfactory lobes tumors, seizures, and changes in mentation are common. When cerebral cortical tumors are present, pacing and wide circling are common. Tumors of the brainstem or cerebellum may cause vestibular dysfunction, resulting in head tilt, circling, lack of balance, wide-based stance, altered gait, and ataxia.
The most commonly reported clinical sign in dogs with secondary brain tumors is a change in mentation. Depression, lethargy, and decreased mentation are also common when there is elevated pressure in the CSF. Additionally, secondary brain tumors in dogs can often lead to excessive thirst, urination, and hunger (polyphagia).
How are brain tumors in dogs diagnosed?
If your dog is showing any clinical signs that may be associated with brain tumors, your veterinarian will likely perform a complete physical examination and take a detailed history.
Additional diagnostics that may be performed include:
Complete blood count (CBC) - This test measures the number of different types of cells in the blood and can help to rule out other possible causes of your dog's symptoms.
Biochemical profile - This test measures the levels of enzymes and other substances in the blood and can help to rule out other possible causes of your dog's symptoms.
CT scan or MRI - A brain CT scan or brain MRI may be recommended to get a more detailed view of the brain and to help determine the type of brain tumor present.
CSF analysis - This test involves collecting a sample of the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord and can be helpful in diagnosing meningeal disease or lymphoma.
Biopsy - Definitive diagnosis often requires a biopsy of the brain tumor. This can be done surgically or with needle aspiration.
How are brain tumors in dogs treated?
Treatment for brain tumors in dogs depends on the type of brain tumor present, as well as the location and size of the tumor. Surgical removal is the treatment of choice for accessible brain tumors in dogs. The goals of treatment are to control seizures, relieve brain pressures, and shrink or remove the brain tumor.
Surgical treatment
Surgery can involve the removal of some tumors, reducing the size of others, and obtaining tissue samples for testing.
Chemotherapy
Chemotherapy can be given to dogs as a complement to surgery, or instead of surgery and radiation therapy. However, there is not much information available on using chemotherapy for brain tumors in dogs.
Radiation therapy
Radiation therapy can be effective for dogs, reducing the size of tumors and seizure frequency for a prolonged period of time. Additionally, it can help to ease other clinical symptoms.
Supportive therapy for brain tumors in dogs
Some forms of supportive therapy for dogs who have brain tumors include giving them anticonvulsants to help with seizures and also treating any cerebral edema. Some common medications used are phenobarbital and levetiracetam for managing seizures, while prednisone can be useful in reducing inflammation and cerebral edema.
What is the prognosis for brain tumors in dogs?
The prognosis for dogs with brain tumors is unfortunately not good. Without treatment, the average survival time is only 70 days. Different types of brain tumors in dogs have varying mean survival times so it is best to discuss with your veterinarian or neurologist for further information and what is applicable to your dog.
Brain tumors in dogs are a serious condition that can lead to a wide variety of symptoms, with seizures being the most common. If your dog is displaying any signs such as seizures and/or change in mentation or behavior, it is important to take them to the veterinarian for an evaluation. Diagnostic tests such as a CT scan or MRI may be recommended in order to determine the type and location of the brain tumor. Treatment options include surgery, radiation therapy, and chemotherapy, though there is not much information available on using chemotherapy for brain tumors in dogs.
If you have any further questions or concerns, please do not hesitate to reach out to your veterinarian.