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Health condition · Clinically reviewed

Astrocytoma, WHO CNS5 grading, molecular markers and modern neuro-oncology.

From curable grade 1 pilocytic astrocytoma to grade 4 glioblastoma - a stepped, evidence-based, MDT-led plan tailored to your tumour\'s molecular profile.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a UK-registered clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, NHS England, WHO CNS5 (2021) classification and peer-reviewed neuro-oncology literature.

  • 03

    Current for 2026

    Reflects the WHO CNS5 reclassification, vorasidenib approval for IDH-mutant glioma and current UK neuro-oncology practice.

Key facts

Astrocytoma at a glance.

The essentials, in plain English - what it is, how the WHO CNS5 grading works, and how it is treated in the UK today.

  • What it is

    A tumour arising from astrocytes, the star-shaped glial cells of the brain and spinal cord. The commonest primary brain tumour in adults.

  • WHO CNS5 (2021)

    Classified by grade (1 to 4) AND molecular markers together, not histology alone. IDH mutation, ATRX loss, 1p/19q, MGMT and H3K27 all matter.

  • Low-grade

    Pilocytic (grade 1) is often curable with surgery. Diffuse astrocytoma IDH-mutant (grade 2) is indolent but tends to progress over years.

  • High-grade

    Anaplastic (grade 3) and glioblastoma (grade 4) behave aggressively. Median survival in glioblastoma remains around 15 months on standard care.

  • Key change in 2021

    IDH-mutant grade 4 tumours are now called "astrocytoma IDH-mutant grade 4" - not glioblastoma. GBM is reserved for IDH-wild-type disease.

  • Definitive test

    Tissue biopsy with molecular profiling. MRI suggests, molecular pathology confirms and directs treatment.

Why this guide matters

Molecular pathology now drives treatment.

Astrocytoma is not one disease. The three points below shape the entire plan - and everything else on this page.

  • Grade AND molecular markers

    WHO CNS5 (2021) combines histology with IDH, ATRX, 1p/19q, MGMT, H3K27 and other markers to define the true tumour type.

  • Surgery still comes first

    Maximum safe resection - with awake mapping and 5-ALA fluorescence where appropriate - remains the single most powerful intervention.

  • Targeted therapy is arriving

    Vorasidenib for IDH-mutant grade 2, dabrafenib/trametinib for BRAF-mutant tumours and everolimus for SEGA are reshaping outcomes.

How the diagnosis is made

From first symptom to a molecular diagnosis.

The steps a UK neuro-oncology service typically follows, in order - so you know what to expect and why each step matters.

  1. 01

    Assessing

    Focused neurological history

    New headache, seizure, focal weakness, personality or cognitive change, visual disturbance or endocrine symptoms all raise suspicion.

  2. 02

    Assessing

    Neurological examination

    Cranial nerves, motor and sensory testing, coordination, visual fields and cognitive screen guide the likely site.

  3. 03

    Assessing

    MRI brain with gadolinium

    The primary imaging test. Adds MR spectroscopy and perfusion where available to characterise the lesion and grade non-invasively.

  4. 04

    Confirming

    Advanced imaging and PET

    DTI for tract mapping before surgery. Amino-acid PET selectively for grading, biopsy targeting and treatment response.

  5. 05

    Confirming

    Tissue biopsy

    Stereotactic or open biopsy provides the definitive diagnosis. No molecular profile can be built without tissue.

  6. 06

    Confirming

    Molecular profiling

    IDH1/2, MGMT promoter methylation, ATRX, TP53, 1p/19q, EGFR amplification, H3K27 and BRAF - the modern minimum panel.

  7. 07

    Planning

    Neuro-oncology MDT and counselling

    Case reviewed by neurosurgery, neuro-oncology, radiation oncology, neuroradiology and pathology. Genetic counselling for NF1, tuberous sclerosis or Li-Fraumeni.

Typical timeline: imaging within days, biopsy and molecular profile within weeks, MDT plan shortly after.

Symptoms

What astrocytoma can look like.

Symptoms depend on where the tumour is. Headache, seizure and progressive focal signs are the classic combination - but presentation varies widely.

  • Persistent headache

    Often worse in the morning, on waking or with cough and straining. Any new or changing headache pattern in an adult deserves review.

  • Seizures

    A first-ever adult seizure is a red flag for a structural cause - up to a third of low-grade gliomas present this way.

  • Focal neurological deficit

    Weakness, numbness, speech disturbance or clumsiness on one side, developing over days to weeks rather than seconds.

  • Cognitive and personality change

    Memory slips, slowed thinking, uncharacteristic irritability or apathy noticed first by family and colleagues.

  • Visual symptoms

    Blurred vision, field loss or double vision - especially with optic-pathway or occipital lesions.

  • Endocrine disturbance

    Hypothalamic or suprasellar tumours can disturb thirst, appetite, growth, puberty, periods and sleep.

  • Nausea, vomiting and drowsiness

    Signs of raised intracranial pressure, often together with new headache and papilloedema on eye examination.

  • Red flag - rapid deterioration

    Sudden severe headache, reduced consciousness, new focal deficit or uncontrolled seizure needs emergency assessment.

Treatment

How astrocytoma is treated in the UK.

Surgery first where possible, radiotherapy and chemotherapy tailored to grade and molecular profile, and a growing set of targeted therapies for specific subtypes.

  • Maximum safe resection

    The first step wherever the tumour is accessible. Awake craniotomy, intraoperative mapping, 5-ALA fluorescence and intraoperative MRI push resection safely.

  • Watch and wait (selected low-grade)

    Small, asymptomatic, low-risk IDH-mutant grade 2 disease may be observed with serial MRI, deferring radiation and chemotherapy until progression.

  • Radiotherapy plus PCV

    For higher-risk low-grade and anaplastic disease. Procarbazine, CCNU and vincristine after focal radiotherapy per RTOG 9802 and CATNON.

  • Stupp regimen (glioblastoma)

    Standard of care in grade 4 GBM. Maximum safe resection, then 60 Gy focal radiotherapy with concurrent temozolomide, followed by 6 cycles of adjuvant TMZ.

  • Vorasidenib for IDH-mutant

    The first targeted therapy for residual or recurrent IDH-mutant grade 2 astrocytoma. FDA approved 2024, available in the UK through trials and named-patient routes.

  • BRAF and MEK inhibitors

    Dabrafenib with trametinib for BRAF V600E-mutant pilocytic astrocytoma and pleomorphic xanthoastrocytoma. Approved paediatric option.

  • Everolimus for SEGA

    An mTOR inhibitor that shrinks subependymal giant cell astrocytoma in tuberous sclerosis, often avoiding or delaying surgery.

  • Tumour Treating Fields (Optune)

    Wearable scalp arrays delivering alternating electric fields. Added to adjuvant TMZ in selected newly diagnosed GBM - modest survival gain.

  • Recurrent-disease options

    Bevacizumab (Avastin) for symptom control, re-irradiation, lomustine, dose-dense TMZ, TTFields and clinical trials tailored to molecular profile.

  • Rehabilitation and palliative care

    Neuro-rehabilitation, specialist nursing, seizure control, psychological support and early palliative-care involvement run alongside oncology.

What this guide is based on

The sources behind every claim on this page.

UK and international guidance and pivotal clinical trial evidence, current at the time of last review.

Key references

Guidelines, classifications and pivotal trials.

A quiet reminder

This guide is for information, not medical advice.

Your neuro-oncology team knows your tumour, your molecular profile and your history - they can tell you which parts of this guide apply to you.

  • WHO Classification of Tumours of the Central Nervous System, 5th edition (WHO CNS5, 2021).

  • NICE. Brain tumours (primary) and brain metastases in adults (NG99).

  • NHS England. Adult brain and CNS tumour service specifications.

  • EANO. Guidelines on the diagnosis and treatment of adult diffuse gliomas.

  • Stupp R et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. NEJM.

  • INDIGO trial. Vorasidenib in IDH-mutant low-grade glioma. NEJM 2023.

Red flags

When to seek urgent help.

Most concerns can wait for a routine appointment. These are the situations that cannot - and where emergency assessment or 999 is the right call.

  • First adult seizure

    Any new seizure in an adult needs urgent brain imaging - a structural lesion, including astrocytoma, must be excluded.

  • Rapidly progressive neurological deficit

    Weakness, speech loss or visual change worsening over days rather than months warrants emergency neurosurgical assessment.

  • Raised intracranial pressure

    Morning headache with vomiting, drowsiness or papilloedema suggests mass effect and possible hydrocephalus.

  • Change in personality or cognition

    Uncharacteristic behavioural or memory change with headache or focal signs is not "just stress" - image the brain.

  • Post-operative deterioration

    New focal deficit, reduced consciousness or seizure clusters after surgery need immediate neurosurgical review.

  • Status epilepticus

    Continuous or clustered seizures lasting over 5 minutes are a medical emergency at any point in the disease.

  • Signs of herniation

    Fixed dilated pupil, worsening consciousness or new bradycardia and hypertension - call 999 and neurosurgery immediately.

  • Suspected leptomeningeal spread

    New cranial nerve palsies, back pain or cauda equina symptoms may indicate CSF dissemination and need urgent MRI.

  • Treatment toxicity

    Severe cytopenia on temozolomide, unexplained fever, bleeding, or unusual bruising needs same-day oncology review.

Living with it

A serious diagnosis, a supported path.

Four things that consistently make the biggest difference - staying inside the MDT, respecting driving rules, bringing a second listener, and using both NHS and charity support.

A quiet reminder

You do not have to carry this alone.

Specialist nurses, rehabilitation teams, psychologists and charities are part of the care - ask what is available and use it early.

  1. 01 Team

    Stay inside the MDT

    Neurosurgery, neuro-oncology, radiation oncology, neurology and specialist nursing all input. Ask who your key contact and CNS is.

  2. 02 Driving

    DVLA rules matter

    Seizures, craniotomy and certain tumour types all trigger driving restrictions. Declare early - your consultant can advise on timing.

  3. 03 Family

    Bring someone to appointments

    Cognitive load and information volume are high. A second listener remembers questions and next steps you may miss.

  4. 04 Support

    Use charity and rehab support

    The Brain Tumour Charity, Brain Tumour Research and Maggie's all offer clinical, practical and emotional support - alongside NHS rehabilitation.

Frequently asked

Everything we get asked about astrocytoma.

Quick answers on grading, molecular markers, the Stupp regimen, vorasidenib and outlook.

  • What is an astrocytoma?

    An astrocytoma is a primary brain or spinal cord tumour that grows from astrocytes, the star-shaped glial cells that support neurons. It ranges from slow-growing grade 1 pilocytic astrocytomas, often curable with surgery, to grade 4 tumours - the aggressive group historically called glioblastoma.

  • How does the WHO 2021 classification change things?

    WHO CNS5 (2021) grades tumours using histology AND molecular markers together. IDH status, ATRX loss, 1p/19q codeletion, MGMT methylation, H3K27 mutation and other markers all sit alongside the microscope findings. Crucially, IDH-mutant grade 4 tumours are now called "astrocytoma IDH-mutant grade 4" - the term glioblastoma is reserved for IDH-wild-type grade 4 disease, which behaves differently.

  • Do I really need a biopsy if the MRI is characteristic?

    In almost every case, yes. MRI, spectroscopy and perfusion are strongly suggestive but cannot deliver molecular profiling. Vorasidenib, temozolomide response, PCV chemotherapy decisions, trial eligibility and prognosis all depend on knowing IDH, MGMT, 1p/19q, ATRX, H3K27 and other markers - and that requires tissue.

  • What is the Stupp regimen?

    The Stupp regimen is the international standard of care for newly diagnosed glioblastoma. It combines maximum safe surgical resection, six weeks of focal radiotherapy (typically 60 Gy) with daily concurrent temozolomide, then six cycles of adjuvant temozolomide. Selected patients also use Tumour Treating Fields (Optune). MGMT-methylated tumours respond better than unmethylated tumours.

  • What is vorasidenib and can I get it in the UK?

    Vorasidenib (Voranigo) is the first targeted therapy for IDH-mutant grade 2 astrocytoma and oligodendroglioma. In the INDIGO trial it significantly delayed disease progression compared with placebo. It was FDA approved in 2024. In the UK it is available through clinical trials and named-patient or early-access routes while NHS commissioning is finalised - your neuro-oncology team will know current access options.

  • What is the outlook for glioblastoma?

    Glioblastoma remains a serious diagnosis. Median survival on standard Stupp therapy is around 15 months, with a small but real long-term survival tail, particularly in MGMT-methylated tumours and in younger patients with good performance status. Molecular subtype, extent of resection, age and access to trials all matter, and outcomes for IDH-mutant grade 4 astrocytoma (no longer called GBM) are meaningfully better.

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