Brain metastases: what options actually exist today
The most common brain tumour in adults — and the one whose outlook has changed most in the last decade.
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.
Gliomas are tumours arising from glial cells, the supporting tissue of the central nervous system. They do not come from neurons, but from the cells that feed, insulate and support them.
They are the most common group of primary brain tumours — those originating in the brain itself, unlike brain metastases, which arrive from another organ.
The first thing to understand: "glioma" describes a family, not a specific disease. A low-grade glioma in a young patient and a glioblastoma are very different entities, with treatments and outlooks that bear no resemblance. Before searching for figures online, you need to know exactly which type it is.
How they are classified today
Classification changed substantially in recent years. It used to rest almost entirely on how the tumour looked under the microscope. Today the World Health Organization integrates histology with molecular markers, because these better predict tumour behaviour and treatment response.
- IDH mutation. The most decisive. IDH-mutant gliomas generally follow a more favourable course than IDH-wildtype tumours of the same grade.
- 1p/19q co-deletion. Defines oligodendroglioma and is associated with better chemotherapy response.
- MGMT promoter methylation. Predicts better response to temozolomide.
- ATRX, TERT, EGFR alterations and others, which refine the classification.
The grades
| Grade | Behaviour | Examples |
|---|---|---|
| 1 | Very slow growing, well circumscribed. Potentially curable with complete resection. | Pilocytic astrocytoma |
| 2 | Low grade, infiltrative and slow growing. Can transform over time. | IDH-mutant astrocytoma, oligodendroglioma |
| 3 | High grade, more aggressive with greater proliferative activity. | Anaplastic astrocytoma |
| 4 | The most aggressive, fast growing with extensive infiltration. | Glioblastoma |
Symptoms
These depend far more on where the tumour is than on its type:
- Seizures. In many patients with low-grade gliomas these are the first manifestation, in a previously healthy person.
- A new headache pattern: different from usual, worse in the morning, capable of waking you at night, worse on coughing or bending.
- Focal neurological deficit: one-sided weakness, speech disturbance, visual field loss, clumsiness of one hand.
- Cognitive or behavioural change: slowing, memory lapses, irritability, apathy. Sometimes family notices before the patient does.
- Nausea and vomiting from raised intracranial pressure.
Seek care without delay for: a first seizure in adulthood, a headache clearly different from usual that progresses over weeks, progressive one-sided weakness or numbness, or personality and language changes the family perceives as new.
Diagnosis
- MRI with contrast. The central study. Defines location, size, relationship to functional areas and enhancement pattern.
- Advanced sequences: spectroscopy, perfusion and diffusion help estimate aggressiveness and distinguish tumour from other lesions.
- Functional MRI and tractography. Map language and motor areas and fibre tracts, to plan a resection that respects them.
- Biopsy or resection. The definitive diagnosis always comes from tissue. No image replaces histological and molecular analysis.
The role of surgery
- Obtain tissue for histological and molecular diagnosis, which determines everything that follows
- Reduce tumour bulk, relieving pressure and symptoms
- Improve the effectiveness of subsequent radiotherapy and chemotherapy
There is consistent evidence that in high-grade gliomas, a more extensive resection is associated with better outcomes. But there is a clear limit: resection must never come at the cost of important neurological function. A patient with more tumour removed and a hemiplegia has gained nothing.
How that tension is resolved
- Neuronavigation: instruments are displayed in real time over the patient's MRI with sub-millimetre accuracy
- Intraoperative neuromonitoring: watches motor and sensory function throughout and warns before damage occurs
- Awake craniotomy for tumours near language areas: the patient speaks during surgery while critical zones are mapped
- 5-ALA fluorescence: tumour tissue glows under blue light, helping define the tumour edge
- Intraoperative ultrasound to update imaging as the brain shifts during surgery
When the tumour sits where safe resection is not feasible, a stereotactic biopsy is performed: through a small opening and guided by navigation, a sample is obtained with millimetre precision to reach the diagnosis.
After surgery
Treatment is defined by a multidisciplinary board — neurosurgery, oncology, radiation oncology and neuropathology — with the molecular result in hand:
- Radiotherapy: standard in high-grade gliomas and in some low-grade tumours with risk factors
- Chemotherapy: temozolomide is the most used agent; the PCV regimen is used in oligodendrogliomas
- Targeted therapies according to specific molecular alterations, an actively developing field
- Follow-up with serial MRI at defined intervals
Talking about prognosis honestly
Prognosis varies enormously between types: a completely resected pilocytic astrocytoma can be cured, while glioblastoma remains a serious diagnosis despite advances.
That said, three things are worth keeping in mind:
- Figures circulating online are medians from large populations, often from older studies. They do not predict an individual case.
- Molecular profiling has changed the outlook for many subtypes compared with what was published a decade ago.
- Age, functional status and extent of resection all influence outcome significantly.
The prognosis conversation should happen with the treating team, with the complete molecular diagnosis available and in the context of the individual patient. It deserves time and should not be settled by a search engine.
What patients ask most
Is a glioma always cancer?
Gliomas are central nervous system tumours and behave as neoplasms, but their aggressiveness varies enormously by grade and molecular profile. A grade 1 pilocytic astrocytoma can be cured with complete resection, while a grade 4 glioblastoma is highly aggressive. There is no general answer without knowing the exact type.
Can a glioma be completely removed?
It depends on type and location. Grade 1 gliomas are usually well circumscribed and can be removed entirely. Infiltrative gliomas, however, extend microscopically beyond what is visible on MRI, so the goal is maximal safe resection without compromising important neurological function.
What is awake brain surgery?
A technique used when the tumour lies near language or motor areas. The patient is woken during part of the operation and performs tasks — speaking, naming objects, moving a hand — while the surgeon stimulates the cortex and maps which areas cannot be removed. It allows more tumour to be resected while preserving critical function.
Why does molecular testing matter so much?
Because it determines the exact diagnosis, guides treatment and predicts prognosis better than microscopic appearance alone. Markers such as IDH mutation, 1p/19q co-deletion and MGMT methylation change both tumour classification and chemotherapy choice. Without them the classification is incomplete.
Are gliomas hereditary?
The vast majority are sporadic and not inherited. Only a very small percentage are associated with rare genetic syndromes such as neurofibromatosis, Li-Fraumeni syndrome or Turcot syndrome. Having a relative with a glioma does not generally imply elevated risk.
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.
