We often regard dogs as man’s best friend because dogs have shared intimate relationships and companionship with us.

It is heartbreaking when you lose your lifelong friends (dogs) to deadly conditions such as cancer, often referred to as a tumor.

Cancer is a leading cause of death amongst both humans and animals globally. Resulting in multiple deaths because of its tissue invasiveness, lack of effective therapies and difficulties in management.

What is a brain tumor in dogs?

Tumor usually originates from changes or mutations that occur in normal body cells. The brain is composed of neurons, meninges (brain covering), blood vessels, and germ cells.

Brain tumors in dogs is classified into primary and secondary. The Primary brain tumor arises from cells resident within the brain.

In contrast, a secondary brain tumor develops because of the movement of tumor cells from other body organs into the brain (metastases). A secondary brain tumor can extend tumors present in the liver, spleen, kidney, lungs and other vital body organs.

In dogs, a brain tumor can develop at any age, although more common in older dogs. Apart from resulting in death of affected dogs, brain tumors can affect normal blood circulation within the brain, resulting in bleeding. In addition, tumors can increase pressure within the skull and cause the accumulation of fluid in the brain.

Tumors are more common in dogs compared to other domestic animals. Brain cancer mainly occurs in dogs above five years of age. Also, the most common sites for cancer in dogs are the brain, skin and circulatory system (blood).

Dogs suffering from brain tumors can exhibit many changes in physical and neurological behavior. The clinical signs of brain cancer depend on the tumor location and the specific structures affected in the brain.

The observed symptoms include body weakness, circling, difficulty with vision, seizures, convulsions, bloody discharge from the nose, reduce appetite, decreased awareness, sneezing, muscle weakness, lack of body coordination, increased sensitivity to neck pain and tilting of the head.

Some classes of primary brain tumors: meningioma, pituitary adenoma, glioma, and adenocarcinoma.

However, meningioma is the most popular primary brain cancer in dogs. This tumor develops from the outer brain covering rather than the cells in the brain.

The most frequently observed secondary tumors of dogs include metastases from the mammary gland, prostate gland, local extension of nasal adenocarcinoma and lung adenocarcinoma.

What is the life expectancy of a dog with a brain tumor?

The life expectancy and survival rate of dogs with brain tumors depend mainly on the type of brain tissue affected, location of the tumor, the health status of the affected animal, availability of surgical intervention, the rate of growth of the tumor, and the method of managing the brain condition.

Foretelling the median survival time of dogs with a brain tumor is challenging.

The average life expectancy is 1-6 months for dogs managed with glucocorticoids, about 12-20 months for conditions contained with surgery and radiation, and 8- 14 months for dogs treated with radiation only.

What breeds of dogs are prone to a brain tumor?

Certain breeds of dogs, such as Boxer, Golden Retriever, Old English sheepdog, Terrier, and Doberman, are more predisposed to brain tumors.

They are primarily brachycephalic breeds (small head and nose). Studies have revealed that Golden Retrievers have the highest prevalence of brain cancer, mostly meningioma (benign tumor of the membranes covering the brain).

Causes of a brain tumor in dogs

Causes of brain tumors can be traumatic, chemical, nutritional, hereditary and immunologic.

Genes responsible for specific tumor types can be transferred from parents to their offspring. Excessive consumption of grains can predispose dogs to a tumor by suppressing their immune system.

Also, some cereals are high in acrylamide, which is a carcinogenic compound (cancer-causing agent).

What makes your dog prone to a brain tumor

Two critical predisposing factors to brain cancer in dogs are old age and genetics.

Old age is a vital contributor to the development of cancer both in animals and humans. Older dogs have suppressed immune responses to diseases. Hence, they become more susceptible to cancer.

The genetic make-up of dogs is an essential factor in tumor development. It is very possible for harmful cancerous genes to be transferred from one generation to another during pregnancy.

Genetically acquired tumors are challenging to manage because such tumors are hereditary and can only be tackled by sophisticated techniques used in medicine, such as gene editing to knock out harmful genes from the body.

The environment is also an essential component of cancer. Dogs can become exposed to cancer-causing and toxic agents within the environment they live in.

Dog owners need to ensure there are no carcinogenic materials in their dog housing system to reduce the chances of tumor development.

Treatment for dogs with a brain tumor

The first step a dog owner should take when a dog is suspected of suffering from a brain tumor based on clinical signs is to visit a registered Veterinarian for efficient medical care. The management options include surgical therapy, chemotherapy and radiotherapy.

The choice of treatment depends on the patient’s clinical condition, cost of treatment, and the economic status of the dog owner.

Brain tumors in dogs treated with radiotherapy revealed a higher survival rate than chemotherapy and surgical removal of tumors. Dogs with localized brain tumors usually have a better prognosis. Brain surgery is an essential consideration for complete tumor removal, partial removal and biopsy collection.

Chemotherapy involves the use of drugs meant to disrupt the metabolism and survival of tumor cells.

Such drugs include alkylating agents (lomustine, carmustine, and temozolomide), antimetabolic drugs (Cytosine arabinoside) and ribonucleotide reductase inhibitors (hydroxyurea).

All these agents can reduce brain tumor size in dogs and improve clinical outcomes. Radiotherapy and chemotherapy can be combined to improve patient outcomes.

Brain tumors are often difficult to manage because of their location and the tissues they affect. A strong skull surrounds the brain, and a fascinating fact is that “brain tissues do not regenerate”.

Therefore, the surgical removal of any affected brain tissue can have detrimental effects on the affected dog because very vital and sensitive tissues could be affected.

Palliative drugs useful in the management of brain tumors include:


These can reduce swelling associated with a brain tumor. Asides from reducing brain swelling (oedema), they are effective at retarding the growth of certain brain tumors, e.g., lymphoma.

Using corticosteroids has side effects in affected dogs, which include increased water intake and hunger.

These drugs can cause dogs to sleep more frequently, but most patients adapt to the drug after some time.

Antiepileptic drugs

Their primary mechanism of action is to reduce involuntary body movement and muscle contraction, which are brain tumor complications. Examples include Bromide, phenobarbital, and levetiracetam.

What are the chances of my dog surviving a brain tumor?

Prognosis, which predicts the likely course and outcome of a medical condition based on medical knowledge and experience, informs about the chances of recovery and survival from the disease.

Expressing the prognostic information about brain cancer in dogs is often done using the survival period from discovery or detection until euthanasia, where the tumor cannot be eliminated.

Still, the patient can be preserved for additional time. The prognosis of brain tumor cases improves with early detection, and it varies with the specific nature and type of the tumor, treatment options and interventions employed.

The prognosis of brain tumors in dogs is discussed in this article with a bias for meningioma, the most common brain tumor. In cases of meningioma, most patients have a high quality of life; they live pain-free and are active until euthanasia.

Treatment options available for meningioma include steroid administration and medication for seizures.

The prognosis is very poor for this option as most dogs survive for only about three months; this period can be extended to about six months when hydroxyurea, a very well tolerated and relatively safe drug, is used instead. Surgical intervention alongside hydroxyurea therapy can extend the time before euthanasia to about a year, and if surgery is used with radiation therapy, the survival period can be extended to one and a half years.


This article has provided information about the mode of development of brain tumors in dogs, the life expectancy of dogs with a brain tumor, likely causes, and the support available to dogs living with brain tumors.

Dog owners are advised to pay critical attention to the predisposing causes of brain tumors and ensure adequate care for their pets by:

  • Presenting dogs for a routine medical checkup.
  • Investigating breed predisposition to cancer before the purchase of dogs.
  • Providing good and safe nutrition, which is free from carcinogenic substances.
  • Seeking advice from medical professionals on issues concerning proper housing and management.
  • Avoiding dog exposure to radiation and other environmental toxins.

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