Brain Tumours in Dogs: An Overview
A diagnosis of a brain tumour in a dog is among the most challenging situations an owner can face. These conditions are serious, and the decisions surrounding diagnosis, treatment, and quality of life require careful thought and close collaboration with a veterinary team. Yet advances in veterinary neurology over the past two decades mean that more options exist today than ever before, and some dogs do remarkably well with appropriate management.
Brain tumours can be primary, originating from cells within the brain itself, or secondary, arising from metastatic spread of a tumour elsewhere in the body. Both types produce signs by disrupting normal brain function through direct invasion, compression of surrounding tissue, or increased intracranial pressure.
Types of Brain Tumours in Dogs
Primary Brain Tumours
The most common primary brain tumours in dogs are meningiomas and gliomas. Meningiomas arise from the meninges, the protective membranes surrounding the brain, and are more commonly seen in dolichocephalic breeds such as Golden Retrievers and Boxers. They tend to be slow-growing and relatively well-demarcated, which can make surgical resection more feasible. Gliomas, which arise from the supportive glial cells of the brain, are more often seen in brachycephalic breeds including Bulldogs, Pugs, and Boston Terriers. They are typically more invasive and carry a less favourable prognosis.
Secondary Brain Tumours
Metastatic tumours reach the brain via the bloodstream from primary sites elsewhere in the body, most commonly from haemangiosarcoma, mammary carcinoma, or pulmonary tumours. These are generally associated with a poorer prognosis due to the multi-systemic nature of the disease.
Which Breeds Are Most Affected?
Whilst brain tumours can occur in any breed, certain dogs appear to be predisposed. Boxers, Boston Terriers, Bulldogs, Golden Retrievers, and Dobermanns are among those most frequently diagnosed. Brain tumours are predominantly a condition of middle-aged to older dogs, with the majority of cases occurring in animals over five years of age.
Recognising the Symptoms
The clinical signs of a brain tumour depend on the location within the brain rather than the tumour type itself. Signs may develop gradually over weeks or months, or appear to emerge suddenly when a compensatory mechanism fails.
Common signs include:
- Seizures, which are among the most frequently reported presenting signs, particularly in older dogs with no prior seizure history
- Behavioural changes such as increased aggression, withdrawal, loss of learned behaviours, or unusual vocalisation
- Circling or pacing in one direction
- Head pressing against walls or furniture
- Loss of vision or abnormal eye movements
- Co-ordination problems, stumbling, or falling to one side
- Reduced responsiveness or apparent confusion
- Altered sleep-wake cycles
The onset of new neurological signs in a dog over the age of five, particularly seizures, should always prompt investigation for an intracranial cause.
Diagnosis
Advanced imaging is essential for diagnosing brain tumours. MRI is the gold standard and provides detailed information about the location, size, and characteristics of a lesion. CT scanning is more widely available and can be sufficient in some situations, particularly for surgical planning. Both modalities are performed under general anaesthesia.
Blood tests are used to assess overall health and identify any concurrent disease. Cerebrospinal fluid analysis may provide additional information about the nature of an intracranial lesion, though it carries a small risk of complications in patients with elevated intracranial pressure. A definitive tissue diagnosis requires a biopsy, which may be performed at the time of surgery or, in some cases, via stereotactic guided biopsy techniques at specialist centres.
Treatment Options
Surgery
Surgical removal of the tumour is possible in certain cases, particularly with well-defined meningiomas accessible via craniotomy. Survival times following surgical removal of meningiomas in dogs are reported in the region of seven to twelve months on average, with some individuals surviving considerably longer. Surgery carries significant anaesthetic and operative risk and requires a specialist veterinary neurosurgeon.
Radiation Therapy
Radiotherapy is an effective treatment for a range of brain tumours in dogs and can be used as a standalone treatment or following surgical debulking. It requires specialist equipment and multiple anaesthetic episodes, typically administered in daily fractions over three to four weeks, though hypofractionated protocols requiring fewer sessions are increasingly available. Median survival times following radiotherapy for intracranial meningiomas range from approximately 12 to 24 months.
Medical Management
For dogs where surgery or radiation is not pursued — due to owner preference, financial constraints, or the dog's overall health — palliative medical management aims to reduce intracranial pressure and control seizures. Corticosteroids such as prednisolone are used to reduce perilesional oedema and often produce a marked short-term improvement in clinical signs. Anti-epileptic drugs are used concurrently when seizures are present.
Quality of Life Decisions
Perhaps more so than with any other neurological condition, the diagnosis of a brain tumour requires owners to engage directly and honestly with questions about quality of life and what meaningful time looks like for their individual dog.
Several factors are worth discussing with your veterinary team:
- The dog's current level of awareness, engagement, and apparent contentment
- The frequency and severity of seizures and how well they are controlled
- Whether the dog is eating, drinking, and seeking interaction
- The anticipated progression of signs and the expected timeline
- The physical and emotional capacity of the owner to provide care as the disease advances
There is no single correct answer about when or whether to pursue treatment, and there is no shame in choosing palliative care over aggressive intervention. What matters most is that decisions are made with full information, a clear understanding of the likely trajectory, and the dog's individual experience at the centre of every choice.
Veterinary palliative care specialists and oncology nurses can provide invaluable support during this time, not just for the dog but for the family caring for them.