Glioma: what this diagnosis means and what the options are
"Glioma" is not one diagnosis. That single word covers tumours with radically different outlooks.
Before you read on. This article is general information for
patients. It cannot be used to reach a diagnosis and does not replace a
consultation: similar symptoms can have very different causes, and only an
in-person assessment — your history, your examination and your imaging — can
establish what is happening and what suits you. If something here worries you,
the right step is to discuss it with a doctor, not to draw conclusions.
A brain metastasis is a tumour that did not begin in the brain: it originated in another organ and reached the nervous system through the bloodstream. This differs from a glioma, which arises from brain tissue itself.
Metastases are by far the most common brain tumours in adults: they outnumber all primary brain tumours combined.
An important message up front: the management of brain metastases changed substantially over the past decade. Stereotactic radiosurgery, targeted therapies and immunotherapy altered what is possible. Prognostic figures published ten or fifteen years ago no longer describe the current situation well.
Where they come from
- Lung — by far the most common origin
- Breast
- Melanoma — with a particularly high propensity
- Kidney
- Colon and rectum
In a proportion of patients, the brain metastasis is the first manifestation of a cancer not yet diagnosed. In those cases, staging to locate the primary tumour forms part of the initial workup.
Symptoms
- Headache of a new pattern, typically worse in the morning, capable of waking you at night
- Focal neurological deficit: one-sided weakness, speech disturbance, visual field loss, clumsiness of one hand
- Seizures, sometimes the first manifestation
- Cognitive or personality change: slowing, confusion, apathy
- Nausea and vomiting from raised intracranial pressure
- Unsteadiness when walking or balance disturbance, typical of cerebellar lesions
In a patient with a history of cancer, any new neurological symptom should be evaluated with brain imaging without delay. It should not be attributed to treatment side effects before being excluded.
Diagnosis
- MRI with contrast. The study of choice: it detects small lesions CT misses and defines exact number, size and location — data that determine treatment.
- Head CT. Useful in the emergency setting, but less sensitive.
- Staging studies (PET-CT, CT of chest, abdomen and pelvis) to locate the primary tumour if unknown and assess the rest of the disease.
- Biopsy when the origin is unclear, or when it must be confirmed that the brain lesion is indeed a metastasis and not something else.
That last point deserves emphasis: not every brain lesion in an oncology patient is a metastasis. It may be an abscess, an independent primary tumour, a demyelinating lesion, or radionecrosis from previous treatment. Confirming the diagnosis changes treatment entirely.
Treatment options
Corticosteroids
Dexamethasone reduces oedema around the lesion and usually improves symptoms within hours or a few days. It is symptomatic rather than antitumour treatment, and is titrated to the minimum effective dose because of side effects.
Surgery
- There is a single lesion or few accessible lesions
- The lesion is large and causes mass effect with significant symptoms
- Histological diagnosis is needed because the origin is unknown or uncertain
- There is risk of herniation or hydrocephalus — an urgent situation
- Systemic disease is controlled and the patient's functional status is good
Resection is performed with neuronavigation, intraoperative neuromonitoring and magnification, to remove the lesion while preserving function. Metastases are usually better circumscribed than infiltrative gliomas, which often allows complete resection.
Stereotactic radiosurgery
Delivers a high, highly precise dose of radiation to the lesion in one or few sessions, sparing surrounding healthy tissue. No incision or general anaesthesia is required.
It has become the reference treatment for small and multiple lesions, and is also used after surgery on the resection cavity to reduce local recurrence.
Whole-brain radiotherapy
Irradiates the entire brain. Its use has reduced considerably because of effects on cognitive function, and it is now reserved for widely disseminated disease or specific situations. When used, hippocampal-sparing techniques reduce that impact.
Systemic treatment
Much of the last decade's change sits here. Several targeted therapies and immunotherapies can cross the blood-brain barrier and act on brain metastases, something classical chemotherapy achieved only with difficulty. The choice depends on tumour type and molecular profile.
How the decision is made
- Number, size and location of lesions
- The patient's functional status
- Control of disease outside the brain
- Histological type and molecular profile of the primary tumour
- Previous treatments received
- The patient's own goals and preferences
About prognosis
- Type of primary tumour and its molecular profile
- The patient's functional status
- Control of systemic disease
- Age and number of lesions
Tumour-specific prognostic scales exist that oncologists use to guide decisions. What matters for patients and families is that estimates have improved significantly for several subtypes, and that figures found online usually come from series predating modern radiosurgery and current targeted therapies.
That conversation deserves to happen with the treating team, with the complete diagnosis available and enough time to ask everything that needs asking.
What patients ask most
Can a brain metastasis be operated on?
Yes, in selected cases. Surgery is considered when there is a single lesion or few accessible lesions, when they cause mass effect with significant symptoms, when histological diagnosis is needed, or when there is risk of herniation. It is weighed alongside the patient's functional status and control of systemic disease.
What is stereotactic radiosurgery?
It is the delivery of a high, highly precise radiation dose to the lesion in one or few sessions, sparing healthy brain tissue. It requires no incision or general anaesthesia. It is today the reference treatment for small and multiple metastases, and is also used after surgery to reduce local recurrence.
How many brain metastases can be treated?
There is no fixed number. Stereotactic radiosurgery can treat multiple lesions in a single session, and the limit is set more by total tumour volume, the size of each lesion and the patient's condition than by an exact count. The decision is made by a multidisciplinary board.
Is every brain lesion in a cancer patient a metastasis?
No. It may be an abscess, an independent primary tumour, a demyelinating lesion, or radionecrosis from previous treatment. When there is diagnostic doubt, a biopsy is performed, because treatment changes entirely depending on the real diagnosis.
Do brain metastases always cause symptoms?
No. Some are detected on surveillance imaging in asymptomatic patients, especially in cancer types where routine brain follow-up is performed. Small lesions away from functional areas may cause no clinical manifestation for some time.
Written and reviewed by Dr. Ricardo Bermúdez, neurosurgeon. Last reviewed: 2026-09-09.
General informational content. It is not medical advice, does not create a doctor-patient relationship, and must not be used to self-diagnose or to decide on treatment. Outcomes vary from person to person. If you have symptoms, see a doctor.
