Vet Insights: Everything You Need to Know About Brain Tumors in Dogs

Brain tumors are surprisingly common in dogs, with their symptoms varying based on the tumor's size and location in the brain.

Common signs of a canine brain tumor include walking in circles, head tilting, sudden behavioral changes, abnormal posture, seizures, and loss of balance. Other neurological symptoms, such as difficulty walking or confusion, may also occur. If you notice any of these indicators in your dog, consult a veterinarian promptly to ensure the best possible care.

Brain tumors can develop in dogs at any age, but certain breeds, such as Boxers and Golden Retrievers, are particularly prone to these conditions due to genetic factors. Diagnosis often requires advanced imaging techniques like computed tomography (CT) or magnetic resonance imaging (MRI), which provide detailed views of the brain.

Treatment options for canine meningiomas depend on the tumor’s type and progression. Common approaches include surgical removal, radiation therapy, and chemotherapy, with the latter two often used to shrink brain tumors. Consulting a veterinary specialist is crucial to determining the most effective treatment plan for your dog.

In this article, you'll learn about brain tumors in dogs, including their clinical signs, diagnostic methods, treatment options, and other essential insights.

What are Brain Tumors in Dogs?

Brain tumors are abnormal masses of cells that develop within healthy brain tissue or nearby structures, such as the protective membranes covering the brain. These tumors are typically classified into two categories: benign (non-cancerous) and malignant (cancerous).

In dogs, this condition is further divided into two categories: primary brain tumors, which develop within the brain itself, and secondary tumors, which result from cancer spreading to the brain from other parts of the body.

Moreover, forebrain tumors in dogs often lead to seizures, abnormal posture and movement, sudden vision loss, and notable changes in awareness and behavior. These tumors may also affect the respiratory and cardiovascular systems, leading to further complications. Obtaining a definitive diagnosis is essential for determining the most appropriate course of action as a dog owner.

What are Primary Brain Tumors in Dogs?

In this discussion, we will provide a brief overview of primary brain tumors in dogs. In addition to exploring the risk factors, we will address the common physical and neurological signs associated with this condition. It is important to note, however, that not all brain tumors treated in dogs are primary brain tumors.

Primary brain tumors in dogs include meningiomas, pituitary tumors, gliomas, and choroid plexus papillomas. Each of these tumor types will be examined in greater detail in the sections that follow.

A Quick Look at Canine Meningiomas

Did you know that meningioma is the most common primary brain tumor in dogs? It is important to note, however, that meningiomas are not strictly brain tumors. These tumors develop in the protective membranes covering the brain and spinal cord, with only 14% involving the spinal cord.

Although meningiomas do not originate in the brain, malignant forms can infiltrate brain tissue. These tumors primarily affect adult dogs over the age of 7. Additionally, certain breeds, particularly long-nosed dogs such as Collies, are more predisposed to this type of brain cancer.

Meningiomas in dogs are classified into three types based on histological grading:

• Benign (Grade I): These tumors do not spread to other areas of the body.
  
• Atypical (Grade II): Intermediate-grade tumors with a higher likelihood of recurrence.
  
• Anaplastic or Malignant (Grade III): These aggressive tumors can spread to other organs and tissues.
  

Despite this classification, meningiomas in dogs are always considered malignant (cancerous) and are typically treated through surgical removal.

What are the clinical signs of meningiomas in dogs?

Clinical signs of meningiomas in dogs can vary depending on the tumor's location and progression. Common symptoms include:

• Seizures
  
• Walking in circles
  
• Vision problems, including blindness
  
• Drunken gait (ataxia)
  
• Difficulty walking
  
• Dragging toes
  
• Altered sense of smell: When the meningioma is localized in the frontal lobe, where the olfactory cortex is located, this may result in changes in appetite and behavior.
  

The primary treatment for meningiomas in dogs is surgical removal. Studies involving 101 dogs with surgically treated meningiomas revealed a mean survival time of 386 days. Among these cases, 94% of the dogs survived the surgical procedure. Of the surviving dogs, approximately 50% passed away within the first year, 25% lived an additional 1–2 years, and 15% survived for 2–3 years.

A Brief Overview of Pituitary Tumors

The pituitary gland, located at the base of the brain just below the hypothalamus, is a small but essential organ responsible for producing hormones critical to the body’s overall function.

Tumors that develop in this gland can significantly affect a dog’s quality of life by disrupting hormone production. As they grow, these tumors may also compress nearby nerves and structures, leading to a range of clinical signs.

Corticotroph adenoma is the most common type of pituitary tumor in dogs. While this type of tumor is considered benign because it does not spread to other tissues, its effects on hormone regulation and local structures can still result in severe health complications.

What are the clinical signs of canine pituitary tumors?

Clinical signs of pituitary tumors in dogs often depend on the tumor's size and its impact on surrounding structures, such as the brain and optic nerves. Common symptoms include:

• Difficulty walking: Tumor pressure on nearby brain regions may cause an unsteady gait, weakness, or difficulty coordinating movements.
  
• Worsening or onset of diabetes mellitus: Hormonal disruptions caused by the tumor can lead to new cases of diabetes or aggravate pre-existing diabetes.
  
• Vision loss: Compression of the optic nerves by the growing tumor can result in partial or complete blindness. Affected dogs may bump into objects, hesitate to move, or appear disoriented in new environments.
  

These symptoms tend to develop gradually, underscoring the importance of early detection and consultation with a veterinary specialist for effective management.

Canine pituitary tumors and Cushing's syndrome

A tumor in the pituitary gland can result in Cushing's syndrome, which may be either pituitary-dependent or adrenal-dependent.

Pituitary-dependent Cushing’s syndrome occurs when a pituitary tumor causes the excessive production and release of cortisol into the bloodstream, commonly known as the stress hormone. This condition, also referred to as hypercorticism, arises from the overproduction of adrenocorticotropic hormone (ACTH) by the pituitary gland.

ACTH regulates the adrenal glands, which are responsible for synthesizing cortisol. As a result, the increased levels of ACTH lead to excessive cortisol production, causing the symptoms associated with Cushing’s syndrome.

Clinical signs of Cushing's syndrome in dogs may include:

• Increased appetite
  
• Increased thirst (polydipsia)
  
• Increased urination (polyuria)
  
• Distended abdomen (commonly referred to as a saggy belly)
  
• Hair loss (alopecia)
  
• Dry skin
  

These symptoms often develop gradually and may be accompanied by noticeable changes in behavior, such as restlessness or lethargy, and shifts in energy levels. Fortunately, brain tumors that cause Cushing's syndrome are rare, affecting less than 1% of the canine population.

Treatment for pituitary tumors in dogs primarily involves radiation therapy, especially when the tumor is diagnosed early. Additional treatment options may include surgery and medical management to address clinical signs and improve the dog’s quality of life.

Dogs that undergo radiation therapy for pituitary tumors may survive for up to 5 years. For dogs with pituitary-dependent Cushing’s syndrome, the survival time is typically up to 2 years, regardless of whether they receive treatment.

Gliomas in Dogs: Key Facts at a Glance

Gliomas are brain tumors that develop in the central nervous system from glial cells, which provide support and protection for neurons. In dogs, there are two main types of gliomas:

• Astrocytomas: These tumors are relatively common in both dogs and humans, similar to meningiomas. They arise from astrocytic cells and are often malignant (high-grade). However, low-grade astrocytomas grow more slowly and are less aggressive.
  
• Oligodendrogliomas: These tumors originate from oligodendrocytes, the cells responsible for forming the protective myelin sheath around nerve fibers.
  

They usually occur in older dogs, but can also be seen in younger ones. The average age of onset of astrocytoma in dogs is 9 years.

What are the clinical signs of dog gliomas?

The clinical signs of gliomas in dogs can vary depending on the tumor's location and progression. Common symptoms include:

• Seizures: Often one of the earliest and most noticeable signs of gliomas in dogs.
  
• Mentation changes: Reduced responsiveness to normal stimuli, such as decreased reactions to familiar sounds or commands.
  
• Vestibular disturbances: Disruptions in the vestibular system, which controls balance and spatial orientation. Affected dogs may exhibit head tilts, uncoordinated movements, or difficulty standing.
  
• Vision loss: Sudden or gradual loss of sight, leading to disorientation or clumsy behavior.
  

Because the symptoms depend on the specific brain regions affected by the tumor, they may initially appear subtle but can worsen as the disease progresses. Prompt veterinary evaluation is crucial for accurate diagnosis and timely intervention.

Oligodendrogliomas, on the other hand, develop from oligodendrocytes and are associated with a better prognosis compared to other gliomas. Breeds most predisposed to this type of tumor include the Boston Terrier, French Bulldog, and Boxer. These tumors are most commonly located in the frontal lobe of the brain.

Overall, gliomas are most commonly diagnosed in short-nosed breeds, including Boxer, Boston Terrier, English Bulldog, and French Bulldog.

Treatment typically involves surgical removal of the tumor, often followed by chemotherapy and/or radiotherapy to control remaining tumor cells. The survival time for dogs with gliomas varies depending on the tumor type and treatment:

• Astrocytoma: Survival time ranges from 3–8 months in treated dogs, although some studies report a mean survival time of 743 days.
• Oligodendrogliomas: Mean survival time is approximately 205 days.
  
• Undefined glioma: Mean survival time is approximately 144 days.
  

Choroid Plexus Tumors Demystified

Choroid plexus tumors originate in the ventricles of the brain, where cerebrospinal fluid (CSF) is produced. These rare tumors account for approximately 10% of all primary brain tumors in dogs, with Golden Retrievers showing a higher predisposition.

Choroid plexus tumors can be classified as either benign (papillomas) or malignant (carcinomas), depending on their behavior and growth characteristics.

Choroid plexus tumors in dogs may present with the following clinical signs:

• Head tilt
  
• Ataxia (incoordination)
  
• Horizontal nystagmus (rapid, uncontrolled horizontal eye movements)
  

If the tumor is operable, surgery is typically the preferred treatment method, followed by radiotherapy, with or without chemotherapy, to address remaining tumor cells.

Data on the mean survival time for dogs with choroid plexus tumors is limited due to the rarity of these cases. However, individual reports provide insight:

• One dog survived 25 months after surgery.
  
• Another dog lived 14 months following surgery and radiation therapy.
  
• A third dog treated only symptomatically survived for 15 months.
  

These examples highlight the variability in outcomes based on treatment approaches and individual factors. Further studies are needed to establish comprehensive survival data.

What are Secondary Canine Brain Tumors?

Secondary brain tumors originate elsewhere in the body and metastasize to the brain. This process occurs when tumor cells from a primary tumor break off and travel through the bloodstream or lymphatic system, ultimately establishing themselves in the brain.

Malignant cancers that can spread to the brain in dogs include:

• Melanoma
  
• Mammary carcinoma
  
• Hemangiosarcoma
  

What Causes Brain Tumors in Dogs?

In general, the exact causes of cancer are unknown, and brain tumors in dogs are no exception. However, several factors may increase the risk of developing brain tumors:

• Age: Brain tumors are more common in adult dogs over 7 years of age, though they can occasionally occur in younger pets.
  
• Breed: Certain breeds, such as Golden Retrievers, Boxers, English and French Bulldogs, and Boston Terriers, are more prone to developing brain tumors.
  
• Environmental toxins: Exposure to pesticides, herbicides, or other chemicals may elevate the risk of brain tumors.
  
• Radiation exposure: Prolonged exposure to radiation, similar to its effects in humans, can increase the risk in dogs.
  
• Weakened immune system: Dogs with compromised immune systems may be more vulnerable to tumor development.
  
• Hormonal imbalances: Imbalances in hormones could potentially contribute to tumor growth, though more research is needed.
  
• Diet: Poor nutrition or an improper diet might play a role in increasing risk factors.
  
• Chronic brain inflammation: Long-term inflammation of the brain, caused by infection or injury, may contribute to tumor development.
  

What are the Clinical Signs of Dog Brain Tumors?

Although clinical signs of brain tumors vary by type, the following symptoms may indicate that your dog is affected:

Neurological Signs:

• Vacant episodes (e.g., vacant stares)
  
• Walking in circles
  
• Head tilt
  
• Changes in behavior
  
• Incoordination or wobbliness
  
• Seizures
  

Non-Specific Signs:

• Loss of appetite
  
• Weight loss
  
• Lethargy
  
• Depression
  

If your dog displays any of these signs, it is essential to consult a veterinarian immediately for proper diagnosis and treatment.

How Do Vets Diagnose Brain Tumors in Dogs?

Diagnosing brain tumors in dogs is a complex process that typically requires a combination of diagnostic methods. These may include advanced imaging techniques, thorough clinical evaluations, blood tests, and other specialized procedures.

Abdominal ultrasound and similar diagnostic tests are commonly used to detect signs of metastasis. These procedures help determine if the cancer has spread to other organs, providing critical information for disease staging and guiding treatment decisions.

If your dog is exhibiting signs suggestive of a brain tumor, it is crucial to consult a veterinarian promptly for an accurate diagnosis.

Clinical evaluation and your dog’s medical history

During the initial evaluation, your veterinarian will ask about your dog's medical history, including any past illnesses, the onset of clinical signs, and any noticeable changes in behavior or health. They will then conduct a thorough physical examination, which includes a neurological assessment.

If a brain tumor is suspected, your veterinarian may recommend consulting a neurologist or oncologist for further testing and treatment. The neurological examination assesses your dog's coordination, balance, reflexes, and cranial nerve function. This information helps pinpoint the specific area of the brain that may be affected.

Blood tests

If your veterinarian suspects a brain tumor in your dog, they may recommend blood tests as an essential part of the diagnostic process. These typically include a complete blood count (CBC), which measures levels of red and white blood cells and platelets, and a blood chemistry panel, which evaluates the function of vital organs such as the liver, kidneys, and pancreas.

These tests not only help detect any underlying health issues but also rule out other potential causes of your dog's clinical signs. Additionally, the results can confirm whether your dog is healthy enough to proceed with further diagnostic procedures or treatments.

Imaging techniques

Imaging techniques include computed tomography (CT), magnetic resonance imaging (MRI), and X-rays. We will discuss each of these in detail to provide a clearer understanding.

• CT scans involve placing the dog under general anesthesia while the scanner captures multiple X-ray images from different angles. These images are then processed by a computer to generate cross-sectional views of the brain. Although CT scans provide detailed images, they are not as detailed as those produced by MRI. However, CT scans are still valuable diagnostic tools, particularly when MRI is unavailable.
  
• MRI is considered the most effective method for diagnosing brain tumors in dogs. This technique produces highly detailed images of brain structures, enabling veterinarians to accurately identify the presence, location, and size of a tumor. Similar to CT scans, MRI requires the dog to be under general anesthesia. The procedure uses radio waves and strong magnetic fields to generate precise and detailed images.
  
• X-rays are primarily used to determine whether cancer has metastasized to the lungs, a common site for secondary tumors. They are valuable for assessing the chest cavity and detecting abnormalities in the lungs but are ineffective for examining the brain. The dense structure of the skull prevents X-ray beams from penetrating to visualize the brain's internal structures. For detailed brain imaging, advanced techniques like CT scans or MRIs are required.
  

Electroencephalography (EEG)

An electroencephalogram or EEG records the brain's electrical activity by measuring its signals. While it is used less frequently than imaging techniques, it can provide valuable additional information in certain cases. EEGs are particularly useful for detecting abnormal brain activity, such as seizures, which can be associated with brain tumors.

Cerebrospinal fluid analysis

In certain cases, cerebrospinal fluid (CSF) analysis can aid in diagnosing brain tumors in dogs. CSF is a clear, protective fluid that surrounds the brain and spinal cord, acting as a cushion against trauma.

To conduct this test, your veterinarian will collect a CSF sample, which is then analyzed for the presence of abnormal cells, elevated protein levels, or other indicators that may suggest a brain tumor. This procedure provides valuable diagnostic information, particularly when used in conjunction with other tests.

Biopsy and histopathological analysis

A biopsy involves collecting a portion of the tumor or, in some cases, the entire tumor for laboratory histopathological analysis. This procedure is typically carried out by a veterinary neurosurgeon, who performs a craniotomy (a surgical opening of the skull) to access the tumor.

Depending on the tumor's size and location, the surgeon may remove a sample or the entire mass. Histopathological analysis is vital for determining the tumor’s exact type and whether it is benign or malignant, providing essential information for creating an effective treatment plan.

How Do Vets Treat Brain Tumors in Dogs?

Treatment options for brain tumors in dogs can be categorized as supportive and/or specific.

Supportive therapies focus on managing symptoms and improving quality of life. These may include antiepileptic drugs to control seizures and steroid medications to help reduce brain swelling and potentially slow tumor growth.

Specific treatments target the tumor itself and include surgical excision, radiotherapy, and chemotherapy. For tumors that are inoperable due to their location or size, radiotherapy and/or chemotherapy are typically the most recommended approaches.

Surgery

Surgery aims to remove the brain tumor and is typically feasible when the tumor is located on the brain's surface rather than deep within its structures. Tumors situated deep inside the brain are often inaccessible, as reaching them would risk damaging healthy tissue and causing significant complications.

This method is most commonly used successfully in dogs with meningioma. However, while surgery can provide relief, there is an increased likelihood of cancer recurrence with this type of tumor.

Radiotherapy or radiation therapy

Radiation therapy is an effective treatment option for inoperable tumors located deep within the brain. It can target and destroy the tumor mass without the need for invasive surgery. However, some brain tumors may regrow (recur) after treatment. Additionally, radiation therapy can cause side effects, including ear infections, mouth ulcers, or nausea. These side effects are usually manageable with appropriate medication.

In certain cases, a combination of treatments, such as surgery followed by radiation therapy, may be recommended by your veterinarian to achieve the best possible outcome.

Chemotherapy

Chemotherapy alone is generally not highly effective in treating brain tumors in dogs due to the protective function of the blood-brain barrier (BBB). The BBB acts as a filter, preventing many harmful substances, including most chemotherapy drugs, from entering the brain in significant quantities.
However, targeted chemotherapy presents a more effective option for certain tumors, such as gliomas. This method involves inserting a small catheter directly into the tumor and delivering chemotherapy drugs slowly over several hours, enabling the medication to bypass the BBB and reach the tumor directly.

Can Brain Tumors in Dogs Be Treated Naturally?

It is important to note that natural treatments cannot cure cancer. However, they may support your dog's immune system, aiding in their ability to combat brain tumors and recover more effectively.

Zumalka’s PIPTOPET is a premium natural product designed to support your dog’s overall health and may assist in managing brain tumors and alleviating related symptoms. Its key ingredient, birch polypore (Fomitopsis betulina), is an ancient medicinal mushroom celebrated for its numerous health benefits over centuries.

Studies conducted on dogs, mice, and monkeys have highlighted its antiviral, antibacterial, antitumoral, anti-inflammatory, immune-supporting, and antioxidant properties, making it a beneficial addition to your dog’s wellness plan.

PIPTOPET is an outstanding natural product designed to support dogs with brain tumors and more. By boosting your pet’s immune system, it promotes natural healing and overall well-being. To maximize its benefits, consider incorporating the following remedies from our OPTIMAL KIT into your dog’s treatment plan:

• TONICPET #4: It delivers oxygen throughout your dog’s body, supporting their natural immune response and enhancing their overall quality of life.
  
• TONICPET #5: It supports healthy circulation, promoting the optimal functioning of your dog’s body systems, including the nervous system.
  
• TONICPET #7: It supports your pet in managing brain tumors more effectively by enhancing oxygen circulation to the brain.
  
• TONICPET #10: Cancer cells thrive in acidic environments. This product helps balance your dog’s pH levels, creating an environment that discourages brain tumor growth.
  

Combining PIPTOPET with these homeopathic remedies can improve your dog’s circulation and strengthen their natural defense mechanisms, helping them better manage brain tumors.

Frequently Asked Questions (FAQs)

How common are brain tumors in dogs?

Brain tumors are common in dogs, as they are in humans. Studies suggest an incidence rate of 14.5 cases per 100,000 dogs, while other research indicates that intracranial neoplasms are observed in 2–4.5% of canine cases presented to veterinarians. These findings highlight the importance of early detection and appropriate treatment for affected pets.

How long can my dog live with a brain tumor?

The survival time for dogs with brain tumors depends on the type, size, and location of the tumor. Without treatment, dogs may survive for several months after diagnosis. Surgical treatment, with or without radiation therapy, can extend survival to 15 months or longer.

Dogs diagnosed with pituitary adenomas often live several years with appropriate care, while those with secondary brain tumors typically survive about a month after diagnosis. Early diagnosis and advancements in veterinary care can significantly improve outcomes for many dogs.

What are the final stages of a brain tumor in dogs?

In the final stages of brain tumors, dogs may experience difficulty breathing, loss of appetite, incontinence, blindness, and severe lethargy. If you notice these signs, consult your veterinarian to evaluate your pet’s condition and discuss the best course of action.

In some cases, choosing humane euthanasia can be a compassionate way to prevent unnecessary suffering and ensure your dog’s comfort.

When to euthanize a dog with a brain tumor?

This heartbreaking decision is often necessary when a dog with a brain tumor experiences significant pain, their quality of life steadily declines, and the tumor is inoperable or unresponsive to treatment. Making this choice ensures that your pet is spared unnecessary suffering and remains cared for with love and compassion.

What are the first stage symptoms of a brain tumor?

Seizures are often the first noticeable clinical sign of a brain tumor in dogs. These seizures can be severe, causing excessive drooling, collapse, and loss of bladder or bowel control. Other early signs may include vision loss, profound lethargy, or walking in circles. If you observe any of these symptoms, consult a veterinarian promptly for evaluation and care.

Are dogs with brain tumors in pain?

Brain tumors can cause pain depending on their location and size, as inflammation and pressure on surrounding structures often result. This pressure may lead to signs of discomfort, such as head tilting or other behaviors indicative of pain. Recognizing these symptoms can be distressing, but consulting a veterinarian promptly ensures your dog receives the care and relief they need.

Do brain tumors in dogs come on suddenly?

Brain tumors in dogs may develop suddenly or gradually, but they are often progressive, with symptoms worsening rapidly in most cases. Despite this progression, dogs may still have good and bad days, with periods of improvement followed by a decline.

About the author

Dr. Iuliana Mihai, DVM, MSc, PhD

Iuliana Mihai, DVM, MSc, PhD, is a Bucharest-based veterinary expert specializing in internal medicine and oncology.

Her work has been published in reputable publications such as Veterinary Medicine Journal, Catster.com, Dogster.com, Hepper.com, Meowiz.com, Springnaturals.com, Petkeen.com, and Wilderharrier.com.

She is a malpractice and negligence veterinary consultant and a graduate of The University of Agronomic Sciences and Veterinary Medicine and The Romanian Academy.

Read the complete profile of Dr. Iuliana Mihai, DVM, MSc, PhD (Veterinarian) here.