Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Brain tumors are most common in middle-aged and older dogs. The most frequent sign is new seizures in a dog over about 5 years old. Other signs include behavior changes, circling, head pressing, loss of balance, and vision problems. MRI is the key test. Treatment options range from palliative care with medications that reduce swelling and control seizures, to radiation therapy and surgery, which can extend good-quality life, often for a year or more in some cases.
Signs
- Seizures starting in a middle-aged or older dog
- Behavior or personality changes, confusion, or loss of house training
- Circling, usually in one direction
- Pressing the head against walls or furniture
- Loss of balance, head tilt, or wobbliness
- Vision loss, bumping into things
- Sleeping more, or seeming dull
- Neck pain in some dogs
Emergency signs
Go to an emergency vet for a seizure lasting more than 5 minutes, several seizures in a day, a dog that doesn’t recover between seizures, or sudden severe dullness or inability to stand.
Common types
- Meningioma: the most common. Arises from the brain’s covering and is often more treatable. More common in long-nosed breeds.
- Glioma: arises from brain tissue. More common in flat-faced breeds such as Boxers, Boston Terriers, and French Bulldogs.
- Pituitary tumors and tumors spreading from elsewhere.
Diagnosis
- Neurological exam
- Bloodwork and chest X-rays to look for other disease or spread
- MRI (or CT), the main way to find and characterize a brain tumor
- Spinal fluid analysis in some cases
- A biopsy, sometimes taken during surgery, for a definite diagnosis
Treatment options
- Palliative care: steroids to reduce brain swelling, and anti-seizure medications such as phenobarbital or levetiracetam. This can improve comfort, often for weeks to a few months.
- Radiation therapy, including targeted (stereotactic) radiation. Often extends survival meaningfully.
- Surgery, especially for accessible meningiomas, sometimes followed by radiation.
- Chemotherapy, which has a limited role for most brain tumors.
A veterinary neurologist or oncologist can discuss the expected outlook for your dog’s tumor type and location.
Home care
- Give medications on schedule, and don’t stop steroids or seizure drugs suddenly.
- Keep a seizure diary: date, time, length, and what it looked like. Video can help your vet.
- Keep your dog safe: block stairs and pools, and pad sharp corners.
- During a seizure: move objects away, keep your hands away from the mouth, and time it.
- Watch for steroid side effects: increased thirst, hunger, urination, and panting are common.
- Talk with your vet about quality of life as things change.
What to avoid
- Human seizure or pain medications.
- Combining steroids with NSAIDs, which risks stomach ulcers.
- Unproven supplements or “cures” in place of treatment. Ask your vet before giving any supplement, as some interact with seizure drugs.
Frequently asked questions
How long can a dog live with a brain tumor?
With palliative care alone, often weeks to a few months. With radiation or surgery, many dogs live a year or more, depending on tumor type.
Are brain tumors painful for dogs?
They can cause headaches and discomfort. Steroids and pain relief help. Your vet can help you watch for signs of pain.
Do all new seizures in older dogs mean a brain tumor?
No. Other causes include low blood sugar, liver disease, and toxins, which is why a full workup is important.
Sources
- Merck Veterinary Manual: Tumors of the nervous system
- Song RB, et al. Postmortem evaluation of 435 cases of intracranial neoplasia in dogs and relationship of neoplasm with breed, age, and body weight. J Vet Intern Med. 2013
- Merck Veterinary Manual: Seizure disorders in dogs
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.