Brain Tumors in Dogs

Seizure Emergencies

Most single seizures are not emergencies. These are:

• A seizure lasting more than five minutes
• Repeated seizures without full recovery in between
• Three or more seizures within 24 hours

Any of these needs emergency veterinary care immediately. Prolonged seizure activity causes dangerous overheating and brain injury.

During a seizure: keep your hands away from the mouth, move furniture away, dim lights and reduce noise, and note the time it started. Dogs cannot swallow their tongues.

What Brain Tumors in Dogs Are

A brain tumor is any mass growing within the skull. It causes harm in two ways: by pressing on and displacing brain tissue, and by causing swelling in the surrounding brain. Much of what makes a dog with a brain tumor unwell is the swelling rather than the tumor itself, which is why steroids help so quickly.

Primary brain tumors begin in the brain or its coverings. Secondary tumors have spread there from elsewhere, most often from hemangiosarcoma, mammary carcinoma, lymphoma, or melanoma, or have extended into the skull from a nasal tumor. Establishing which is important, because treatment follows the original cancer.

Most affected dogs are older, typically over five and commonly around nine or ten.

The Main Types

Meningioma is the most common, accounting for roughly half of canine brain tumors. It arises from the membranes covering the brain and grows on the surface, compressing brain tissue rather than invading it. It is often benign or low-grade and typically grows slowly.

Because it sits on the surface, it is the type most amenable to surgery, and it responds well to radiation. This is the diagnosis with the best outlook, and dogs treated for meningioma frequently live a year or two and sometimes considerably longer.

Long-nosed breeds;Golden Retrievers, Labrador Retrievers, German Shepherds, and Collies, are affected more often.

Glioma arises from the supporting cells within brain tissue itself. It grows into the brain rather than alongside it, which makes surgical removal far more difficult. Gliomas range from low to high grade, with the aggressive forms carrying a considerably poorer outlook.

Short-nosed breeds are strongly overrepresented: Boxers, Boston Terriers, French Bulldogs, and English Bulldogs.

Choroid plexus tumors arise from tissue producing the fluid that surrounds the brain. They frequently cause fluid buildup and increased pressure within the skull.

Pituitary tumors arise from the gland at the base of the brain. Many are small and hormonally active, causing Cushing's disease rather than neurological signs. Larger ones press on surrounding brain and cause behavioral and neurological changes.

Lymphoma can involve the brain and is treated as lymphoma rather than as a surgical brain tumor.

Signs to Look For

Seizures are the most common presenting sign, and a first seizure in a dog over about five or six years old is significant. Younger dogs who begin seizing usually have epilepsy; older dogs with new-onset seizures are more likely to have a structural cause, which is why age matters so much in how a first seizure is investigated.

Other signs depend on where in the brain the tumor sits:

• Behavior change: A dog who seems different, withdrawn, unusually irritable, disoriented, or less engaged with the family
• Circling, usually consistently in one direction
• Pressing the head against walls or furniture
• Loss of house training or apparent forgetting of familiar routines
• Vision loss, sometimes affecting one side, with dogs bumping into things on that side
• Wobbliness, incoordination, or weakness, often worse on one side
• Head tilt, falling, or rolling
• Tremors
• Facial changes: A drooping lip, an eyelid that does not close, or an altered facial expression
• Difficulty eating or swallowing
• Neck pain or reluctance to move the head
• Pacing or restlessness, often worse at night

Behavior change is the sign most often attributed to old age. A dog who has become withdrawn, confused, or unusually irritable is frequently assumed to be experiencing normal aging or canine cognitive dysfunction. That assumption is sometimes right. But a relatively sudden change, or one accompanied by any of the physical signs above, warrants a neurological examination rather than acceptance.

How Brain Tumors Are Diagnosed

Neurological examination is the essential first step and costs nothing beyond the appointment. A veterinarian assesses reflexes, cranial nerves, posture, and gait, and can usually localize the problem to a region of the brain. This examination determines whether further investigation is warranted.

Bloodwork and blood pressure rule out causes that mimic brain disease — liver dysfunction, low blood sugar, electrolyte abnormalities, and infection among them. Some of these are treatable and none requires an MRI to find.

Chest X-rays and abdominal imaging look for a primary tumor elsewhere, since secondary spread to the brain is common.

MRI is the definitive test. It shows the tumor's location, size, type characteristics, and the degree of surrounding swelling. It requires general anesthesia and is available at specialty centers and veterinary teaching hospitals. CT is more widely available and can identify larger masses, but it is substantially less informative for brain tissue.

Cerebrospinal fluid analysis is sometimes performed alongside MRI to help distinguish tumor from inflammation or infection.

Biopsy is performed at a small number of centers and gives a definitive tissue diagnosis, though most treatment decisions are made on MRI appearance.

Thinking About Whether to Do the MRI

This is where many families get stuck, and it deserves a direct discussion.

The MRI typically costs between roughly $2,000 and $4,000 including anesthesia, and it does not itself treat anything. It is reasonable to ask whether it is worth it.

The case for doing it: without an MRI, you do not know whether your dog has a benign meningioma that radiation could control for years, an aggressive glioma, an inflammatory condition that would respond to different treatment entirely, or a tumor that spread from elsewhere. These lead to genuinely different decisions. Families who skip the scan and treat with steroids alone sometimes discover months later that a treatable tumor went untreated.

The case against: if you have already decided, for reasons of age, cost, other health conditions, or your own judgment about what your dog would tolerate, that you would not pursue radiation or surgery regardless of the result, then the scan may not change what you do. Steroids and anti-seizure medication can be started without it.

A reasonable middle path exists and is worth knowing about: start steroids and anti-seizure medication, see how your dog responds over a week or two, and use that response to inform whether to proceed with imaging. A dog who improves markedly and stays comfortable buys time to decide.

Ask your veterinarian directly: if the MRI showed a meningioma, what would we do, and what would that cost? That answer usually clarifies the decision faster than anything else.

Treatment

Steroids

Prednisone reduces swelling around the tumor and often produces marked improvement within days; sometimes within hours. Seizures may reduce, alertness returns, and dogs become more like themselves.

This is symptomatic treatment. It does not slow the tumor, and the benefit typically lasts weeks to a few months before signs return. But it is inexpensive, available immediately through your regular veterinarian, and genuinely improves how a dog feels.

Expect increased thirst, urination, appetite, and panting. These are dose-related and often lessen as the dose is reduced.

Anti-seizure medication

Where seizures are occurring, medication such as levetiracetam, phenobarbital, or zonisamide is used to control them. This is important regardless of what else is done, since uncontrolled seizures cause their own harm.

Seizure control is not always complete, and dose adjustments are common in the first weeks.

Radiation

Radiation is the mainstay of treatment for most canine brain tumors, because it reaches tumors surgery cannot and does not require opening the skull.

Modern precise techniques deliver treatment in a small number of sessions, often one to five, rather than the longer courses used previously. Each session requires brief anesthesia.

Results are meaningful. For meningioma, reported median survival after radiation commonly falls in the range of one to two years, and some dogs do considerably better. Gliomas respond less well but still benefit.

The main risks are delayed effects on normal brain tissue, which can appear months later, and temporary worsening from swelling during treatment, managed with steroids.

Surgery

Surgical removal is possible for tumors that sit on the surface of the brain, which in practice means most operable tumors are meningiomas.

It is performed at specialty centers and teaching hospitals by veterinary neurosurgeons. Complete removal is often not achievable because tumor edges blend into surrounding tissue, so surgery is frequently combined with radiation afterward; a combination associated with the longest reported survival for meningioma.

Tumors deep within the brain, and most gliomas, are generally not surgical candidates.

Chemotherapy

Chemotherapy has a limited role for most brain tumors, because many drugs do not cross into the brain effectively. Lomustine and hydroxyurea are sometimes used. For brain lymphoma, chemotherapy is the primary treatment and works differently.

Clinical trials

Brain tumors are an active area of veterinary research, and several teaching hospitals run trials involving newer approaches. Because standard options are limited for gliomas in particular, trials are worth asking about specifically, and some cover treatment costs.

Integrative and supportive care

Practical safety measures matter here more than in most cancers. A dog who may seize needs stairs blocked or supervised, no unsupervised access to water where drowning is possible, and soft surfaces where they rest. Vision loss or incoordination means keeping furniture in familiar positions and avoiding rearranging rooms.

Keep a seizure diary: Date, time, duration, and what the seizure looked like. This is genuinely useful clinical information and it helps your veterinarian adjust medication.

Be cautious with supplements. Several products marketed for canine cognitive support or calming have unclear interactions with anti-seizure medication, and some can lower the seizure threshold. Tell your veterinary team about everything your dog receives, and ask before adding anything new.

No supplement or diet has been shown to treat brain tumors in dogs. 

Comfort care alone

Choosing steroids and anti-seizure medication without pursuing imaging or radiation is a legitimate path, and for many dogs it provides a period of reasonable comfort.

Understand what to expect. Steroid benefit typically lasts weeks to a few months. As the tumor grows, signs return and progress, and seizures may become harder to control. Discuss with your veterinarian in advance what you would want to do if seizures become frequent or prolonged, so that decision is made calmly rather than during a crisis.

What treatment is actually like for your dog

Steroids and anti-seizure medication are tablets at home. The main day-to-day change is the steroid effects: Much more drinking, urinating, appetite, and panting. Provide constant water access and expect more frequent trips outside, possibly overnight.

Radiation involves a small number of visits, each requiring brief anesthesia. Dogs go home the same day. Some become temporarily worse during or shortly after treatment from swelling, which is expected and managed with steroids. Hair loss over the treated area and skin irritation may occur.

Brain surgery requires several days in hospital, often including intensive monitoring initially. Recovery varies with the tumor's location; some dogs are notably better within days, while others need weeks. Most dogs return home on medication that is gradually reduced.

Understanding Prognosis

These are medians across many dogs. Half lived less, half lived longer.

• Steroids alone: commonly two to four months
• Radiation for meningioma: commonly one to two years, with some dogs longer
• Surgery combined with radiation for meningioma: among the best reported outcomes, frequently well over a year
• Radiation for glioma: generally shorter, often under a year, varying considerably by grade
• Untreated: typically weeks to a few months

Tumor type matters most, followed by location and how well seizures can be controlled.

The honest summary is that meningioma is often a manageable disease that can be controlled for a good stretch of time, while high-grade gliomas are considerably harder. This is exactly why knowing which one your dog has changes the conversation.

What It Costs

Costs vary by region and are concentrated at specialty centers. Ask for a written estimate.

• Neurological examination: approximately $150 to $400
• Bloodwork and blood pressure: approximately $200 to $400
• MRI with anesthesia: approximately $2,000 to $4,000
• Cerebrospinal fluid analysis: approximately $300 to $600
• Stereotactic radiation: approximately $6,000 to $10,000
• Conventional radiation course: approximately $5,000 to $9,000
• Brain surgery: approximately $8,000 to $15,000
• Steroids and anti-seizure medication: relatively modest monthly cost

The affordable tier is real and worth naming. Steroids and anti-seizure medication, prescribed by your regular veterinarian, cost a small fraction of the figures above and genuinely improve how a dog feels. A family who cannot pursue imaging and radiation is not left with nothing.

Ask about clinical trials, which sometimes cover treatment.

Living With It Day-to-Day

Keep a seizure diary. Note date, time, duration, and description. Patterns matter for medication decisions.

Adjust the home. Block or supervise stairs, keep furniture in consistent positions if vision or coordination is affected, provide soft bedding, and avoid unsupervised access to pools or bathtubs.

Give medication consistently. Anti-seizure medication works best at steady levels, and missed doses can trigger seizures.

Expect the steroid side effects and plan for them — accessible water, more outdoor trips, and tolerance for a hungrier dog.

Report to your veterinary team: increasing seizure frequency, any seizure over five minutes, worsening weakness or coordination, new behavior changes, loss of appetite, or a decline after a period of stability.

Questions Worth Asking Your Veterinarian or Oncologist

• What did the neurological examination localize, and what does that suggest?
• Have treatable mimics: Liver disease, blood pressure, infection, been ruled out?
• If we do an MRI and it shows a meningioma, what would we do, and what would it cost?
• Is my dog a candidate for stereotactic radiation, and where is the nearest center?
• Would surgery be an option, and would it be combined with radiation?
• What seizure medication do you recommend, and how will we adjust it?
• Are there clinical trials my dog might qualify for?
• What should I expect over the coming months, and what would signal a change?

Thinking About Quality of Life

Brain tumors raise a quality-of-life question that most cancers do not: the dog's personality and awareness can change. A dog who no longer recognizes routines, or seems confused and distressed, is experiencing something different from physical illness, and families often find it harder to assess.

Useful measures here are whether your dog still seems to enjoy things they enjoyed, whether they recognize and engage with the family, whether seizures are controlled, whether they can move safely, and whether they seem distressed or peaceful in ordinary moments.

Keeping written weekly notes matters particularly with this disease, because change is often gradual and memory adjusts to it. Looking back at what you wrote a month ago is frequently more informative than trying to recall it.

Ask your veterinary team what the later stages typically look like, and decide in advance how you would handle prolonged or clustered seizures. Families who have thought this through beforehand consistently describe it as one of the most valuable conversations they had.

Common Questions

My older dog just had a first seizure. Does that mean a brain tumor? Not necessarily, but it warrants investigation. A first seizure in a dog over about five or six is more likely to have a structural cause than in a young dog, where epilepsy is more common. Bloodwork and a neurological examination are the reasonable first steps, and several treatable conditions can cause seizures.

Was my dog in pain during the seizure? No. Dogs are not conscious during a generalized seizure and are not aware of it. It is frightening to watch, and the distress is yours rather than theirs. Afterwards they may be disoriented or tired for a period.

Is the MRI really necessary? It is the only way to know what you are dealing with, and the difference between a benign meningioma and an aggressive glioma changes everything. That said, if you have already decided you would not pursue radiation or surgery regardless, it may not change your plan. Ask your veterinarian what you would do with each possible result.

Can brain tumors in dogs be removed completely? Some surface tumors, particularly meningiomas, can be largely removed, though tumor edges often blend into surrounding tissue so complete removal is difficult. Surgery combined with radiation gives the best reported outcomes for meningioma. Deep tumors and most gliomas are not surgical candidates.

My dog improved so much on steroids. Does that mean it is working? It means the swelling around the tumor has reduced, which genuinely improves how your dog feels. It does not mean the tumor is shrinking. The benefit typically lasts weeks to a few months, which is worth knowing when planning.

Is my dog's behavior change just old age? It might be. But a relatively sudden change, or one alongside circling, head pressing, vision problems, or coordination difficulty, deserves a neurological examination rather than being attributed to aging.

What if we cannot afford imaging and radiation? Steroids and anti-seizure medication cost a small fraction of specialist treatment, are available through your regular veterinarian, and meaningfully improve comfort. That is a legitimate path, not a failure, and many dogs have a reasonable period on it.

This page is for education and does not replace advice from your own veterinarian, who knows your dog. A seizure lasting more than five minutes, or repeated seizures without recovery in between, is a medical emergency.