Brain Tumor in Dogs: Everything You Need To Know

By Petal Smart / August 25, 2018

Perhaps the most horrifying news that any pet owner can receive is that their beloved four-legged companion has a brain tumor. As individuals with a plethora of information at the tips of our fingers, we know all too well just how destructive brain tumors can be. Knowing that our furry companion is going through such pain and discomfort can be incredibly hard and leave pet parents not knowing how to proceed.

We wish more than anything that we had a magical solution to eliminate your dog’s pain and reverse the heart-wrenching diagnosis. In time, with future advancements in science, we hope that this can one day be a reality. Until then, we hope to be able to inform you, our readers, about everything you need to know about brain tumors in dogs. We truly believe that the more you know, the better equipped you will be to handle any situation that comes your way.

Let’s start with the basics.

brain tumor in dogs

What is a Brain Tumor in Dogs

The term tumor refers to any type of abnormal cell growth. Therefore, a brain tumor is an intracranial tumor that originates from the abnormal growth of cells and irregular cellular division within the brain. Brain tumors in dogs are typically found within the brain itself (gray matter). However, it is also possible for the tumors to develop within the skull, the cranial nerves, the meninges (the envelopes that surround the brain), or the pineal and pituitary gland.

Canine brain tumors are diagnosed more often in older dogs. Additionally, studies have found that certain breeds are at a higher risk of developing brain tumors. With that being said, it is entirely possible for a dog of any age and any breed to develop a brain tumor.

There are two types of brain tumors, primary and secondary, and treatment may vary depending on which tumor type is found and how far along the tumor has progressed.

Types of Brain Tumors

Primary Brain Tumors

A primary tumor is one in which the cancer originated in the brain’s cells and its membranes. Extensive research has found that certain types of primary brain tumors affect specific breeds of dogs more than others. This is another example of how knowledge is power. Being aware of the specific ailments that your canine might be prone to is an important first step in catching the disease early on. The sooner any disease is discovered, the better the prognosis for recovery.

The most common primary brain tumors include:

  • Meningiomas
  • Gliomas
  • Choroid plexus papilloma
  • Pituitary adenoma
  • Adenocarcinoma

Secondary Brain Tumors

Secondary brain tumors differ from primary brain tumors because they originate from cancer cells in another area of the body. These cancer cells then spread to the brain through a process referred to as metastasis. Additionally, a secondary brain tumor may develop from adjacent non-nervous tissue that extends into the brain tissue. For example, cancer of the nasal cavity, which extends to the brain.

The most common secondary brain tumors are:

  • Hemangiosarcoma
  • Mammary carcinoma
  • Melanoma

Because secondary brain tumors are the result of metastasis or spread throughout the body, by the time they are diagnosed, the cancer is usually advanced. Therefore, unfortunately, the prognosis for secondary brain tumors is usually not very positive.

Symptoms of a Brain Tumor

As with all diseases, the sooner your vet gives you a brain tumor diagnosis, the greater the chances of effective treatment and recovery. Unfortunately, many early clinical signs of brain tumors appear as what is known as non-specific signs. Non-specific signs are those which could be signs of a multitude of ailments and are not specific to brain tumors alone. Therefore, it can be challenging for pet owners to pinpoint exactly what is going on. However, brain tumors can grow rapidly and aggressively, leaving little time to wait it out and see if the signs go away.

If you notice any of the following changes in your canine, no matter how small, it is imperative that you see a veterinarian for a check-up. An early diagnosis can ultimately be the difference between life and death for a canine with a brain tumor.

Warning Signs of a Brain Tumor

The following is a list of warning signs that are typically associated with a brain tumor in dogs:

  • Seizures (seizures are the most common early clinical sign of a brain tumor in dogs)
  • Depression
  • Head tilting
  • Loss of balance/ “drunken” walk or gait
  • Decreased vision or loss of vision
  • Difficulty swallowing
  • Voice change (being more vocal or hoarseness)
  • Overall weakness and lethargy
  • Strange behaviors (mood changes and increased aggression)
  • Gain or loss of appetite
  • Vomiting
  • Weight loss

Dogs can be quite stoic and are notorious for hiding pain and acting like everything is normal. Knowing your dog’s typical day-to-day behavior is imperative when it comes to recognizing when something isn’t right.

symptoms of brain tumor in dogs

Symptoms of a Brain Tumor in Late Stages

The following are signs of brain tumors in the later stages. Again, if you notice any of these signs, it is paramount that you seek veterinary medical intervention immediately.

  • A continuation of persistent early-stage signs
  • Reclusive or solitary behavior
  • Pacing
  • Walking in circles
  • Confusion
  • Vomiting
  • Pressing against a hard surface
  • Worsening weakness leading to an inability to stand
  • Worsening seizures
  • Paralysis
  • Coma

Symptoms of CriticalStage Brain Cancer

Dogs with brain cancer in the critical stages will commonly have the following signs:

  • Difficulty breathing
  • Continued worsening seizures (seizures will be increased in duration and frequency)
  • Uncontrollable diarrhea
  • Uncontrollable vomiting
  • Sudden collapse
  • Excessive bleeding (internal or external or both)
  • Crying and whining out of pain*

*Just to reiterate, dogs rarely show that they are in pain. Therefore, if your dog is crying out in pain, their discomfort has typically reached an extremely high level.  

What Causes Brain Tumors?

Even with extensive research on the topic, the specific cause(s) of brain tumors in dogs and cats are still relatively unknown. With that said, experts do have several hypotheses as to potential causes. These include:

  • Environmental toxins
  • Dietary factors
  • Chemical toxins
  • Hereditary predisposition
  • Weakened immune system

Studies have discovered links between environmental toxicity and many cancers found in humans. It is pretty safe to assume that if something can cause cancer in people like you and me, it may have similar detrimental results in our four-legged friends. Things like preservatives in our foods, and fertilizers in the soil are all being tied to various illnesses, including cancer.

Furthermore, many experts believe that over-vaccination can also lead to the development of canine cancer. This is a topic that has many concerned, confused, and frustrated. We encourage you, our readers, to do your homework before agreeing to a slew of yearly dog vaccinations. If your dog doesn’t spend time at kennels, they likely don’t need certain shots. If you live in certain parts of the country, you may be able to avoid other vaccines. Nevertheless, be aware of the conditions to which your dog is likely to be exposed, or prone to, and ensure adequate protection. Know what your dog is receiving and be aware of the potential adverse effects. Cancer is only one of the dozens of potential conditions that your dog may face from over-vaccination.

chemicals can cause brain tumor in dogs

Breeds at a Higher Risk for Brain Cancer

Certain breeds are at a higher risk of developing brain tumors. These breeds include:

  • Golden Retriever
  • Boxer
  • Doberman Pinscher
  • Scottish Terrier
  • Old English Sheepdog
  • Collie
  • Boston Terriers

Experts have even found that certain breeds of dogs are at a higher risk of developing certain types of brain tumors. For instance, brachycephalic breeds (those with short noses and flat faces, such as Boxers, English Bulldogs, and Boston Terriers) are at a higher risk of developing gliomas, or tumors of the interstitial tissue of the central nervous system). Conversely, dolichocephalic breeds of dogs (characterized by long heads and noses, such as Collies and Golden Retrievers) are at a higher risk of developing meningiomas, or tumors that develop in the membranes covering the brain.

This is why is it so important to understand the risks to which your dog may be genetically predisposed. By staying informed and being aware, you may prolong your dog’s lifespan.

With that said, although certain breeds may be predisposed, any breed can potentially develop a brain tumor. Typically, brain tumors are diagnosed in dogs over the age of five years, but they can be diagnosed at any age.

Diagnosing a Brain Tumor in Dogs

A brain tumor will often be suspected if your dog does not have a history of neurological issues or other brain condition, and has a sudden onset of the aforementioned symptoms.

In order to make an accurate diagnosis, your veterinarian will perform an array of tests, usually beginning with blood work. The blood tests, including a complete blood count, will alert the vet of any abnormalities and symptoms of infection.

Your veterinarian may also have chest and abdominal x-rays performed. The x-rays and blood work will show whether or not the cancer or other tumors are also located elsewhere in the body.

Next, your vet may perform an imaging MRI (magnetic resonance imaging ) or CT scan (computerized tomography). Because soft tissue brain tumors are not easily detected on an x-ray of the skull, an MRI or CT scan is almost always necessary to make an accurate diagnosis.

An MRI or a CT scan may enable the vet to determine the type of brain tumor present. However, a sample of the tumor obtained by surgery (a surgical biopsy) will be necessary to make a definitive diagnosis. The biopsy will also inform the vet of the malignancy of the brain tumour.

diagnosing brain tumor in dogs

Treating Brain Cancer in Dogs

Treatment for the brain tumor is determined by whether it is a primary or secondary tumor and its location. Typically, surgical removal, radiation therapy, and chemotherapy are the most common methods of treatment for both dogs and cats.

Your veterinarian would determine how best to treat the tumor. One option is total removal of the mass. If total removal is possible, your vet will likely perform surgery as soon as possible. After the surgery is complete, your vet may recommend additional radiation treatments to prevent any regrowth of the tumor.

However, in some cases, it’s considered an inoperable brain tumor. Tumors can develop in locations that are inoperable. In these cases, radiation therapy and chemotherapy can be used to shrink the tumor.

Typically, radiation therapy is the preferred means of treatment over chemotherapy. Chemotherapy drugs have blood-brain barrier limitations that greatly limit their effectiveness.

As you may imagine, treatment options for the brain tumor doesn’t come without its share of side effects. Your veterinarian may prescribe drugs such as anti-seizure medications and other medications to relieve pain and intracranial pressure, and reduce nausea during and after treatment.

After Treatment

During and after treatment, it is imperative for dogs with brain tumors to have regular health evaluations by their veterinarian. Additional CT scans or MRIs may be necessary to confirm whether the treatment and recovery plan is going as expected, or if there are any signs of regrowth.

Additionally, as we previously mentioned, seizures in dogs may be directly associated with brain tumors. Pet parents will need to closely monitor their dog after treatment and make sure there is not increased seizure activity.

Furthermore, brain tumors can lead to weakened swallowing reflexes. This may arise from an accumulation of cerebrospinal fluid within the skull cavity. The weakened swallowing reflexes can lead to the development of aspiration pneumonia (in which food and water that should be swallowed and continue down the esophagus to the stomach, may instead go down the trachea to the lungs). It is very important to be on high alert for any changes in your dog’s health, as the immune system is usually in a fragile state post-treatment.  

Prognosis for Dogs with Brain Tumors

The prognosis for dogs with brain tumors is guarded to fair. Ultimately, the prognosis depends greatly on how quickly the cancer was diagnosed, or how far along it has progressed, and the means of treatment. Therefore, the median survival time can vary.  

Approximate survival time is as follows:

  • 24 months with supportive care alone
  • 612 months with surgery alone
  • 724 months with radiation therapy alone
  • 6 months to 3 years with surgery combined with radiation therapy
  • 711 months with chemotherapy alone

Again, all dogs are different and may react differently to treatment.

preventing brain tumor in dogs

Preventing Brain Tumors

Of course, as a pet parent, you are likely wondering how to prevent your pup from experiencing this horrific condition. Unfortunately, because the definite cause of brain tumors remains unknown, there are no specific means of prevention. However, many studies are continuing to link toxins to various forms of cancers. Toxins are found almost everywhere and there’s no real way to completely eliminate them. However, by limiting vaccinations to only those that are necessary, providing your dog with a speciesappropriate, nutritionally balanced diet, and avoiding environmental toxins such as pesticides, you can help to prevent the development of a slew of ailments, including cancer.

Your pets mean the world to you. Trust us, as dog owners and dog lovers, we completely understand the enormous amount of love you have for your fur children. There is no right thing to say that can reverse the diagnosis of a brain tumor. However, there is hope and you can do all that you can to keep the disease at bay and maintain their quality of life.

Knowledge is power. It is so important to know as much as possible about your dog’s specific breed. If your dog is at a higher risk of developing a brain tumor, it is imperative to be aware of the early symptoms so that you are able to act in a timely and appropriate manner.

Finally, understand your dog’s “normal.” All dogs are different. Some are born couch potatoes, while others are constantly full of energy. Some are picky eaters, while others will devour anything in sight. By knowing your dog’s normal behavior you’ll be able to quickly identify when something is off. If and when this occurs, act straight away. Don’t delay or hope that Fido will soon return to “normal.” A timely diagnosis for any disease, particularly a brain tumor, can truly make a world of difference for your beloved furry companion.



About the author

Petal Smart

Dr. Petal Smart is a veterinarian who, after a brief stint in clinical practice, has been a medical, veterinary, and science editor for the past four years. She has edited hundreds of research studies that have been published in various academic journals, and more recently, she has been editing blog articles on pet health. She holds a DVM (Hons) from the University of the West Indies - St. Augustine. Her pets in the past have included dogs, fish, birds, and a turtle. At times, she also likes to think of herself as a horse whisperer. You can connect with her on LinkedIn.

  • Linda says:

    My dog is on phenobarbital 30mg every 24 hrs. She’s having weakness in her legs and her eyes are darting back and foth. Would it be safe to give her CBD oil? Shes 30lbs 15 yrs
    How much should she have and how often? THANKS!!

  • Linda says:

    My dog is on phenobarbital 30mg every 24 hrs. She’s having weakness in her legs and her eyes are darting back and foth. Would it be safe to give her CBD oil? Shes 30lbs 15 yrs
    How much should she have and how often? THANKS!!

  • Anne Tufts says:

    What does CBD stand for? At what age can your dog start receiving CBD? How often do they receive it? There are certain vaccines that my dog received regularly (i.e. rabies). Which vaccines should they not receive? Are topical treatments for fleas & ticks safe?

  • Karen Houck says:

    This is an incredible website! I learned exactly what I wanted to know, and it was in a readable, easy to understand format. I will refer this site to all of my fur baby loving friends. Thank you!

  • Diana says:

    I saw all the signs, my vet didn’t listen to me and I changed vets, she didn’t listen either. Finding a vet that listens and cares is key. ????

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