Astrocytoma and glioblastoma (GBM)

Astrocytomas are the most common type of brain tumours in both adults and children. They are a type of brain tumour called a glioma.

Gliomas can be put into groups according to how quickly they are likely to grow. There are 4 groups, called grade 1 to 4. Grade 4 astrocytomas are also called glioblastoma. Glioblastoma is also known as glioblastoma multiforme or GBM.

The information on this page is about astrocytomas in adults. We also have information about astrocytomas in children.

Symptoms of astrocytoma and glioblastoma depend on where the tumour is in the brain. Common symptoms include headaches and seizures (fits). 

What are astrocytomas?

Astrocytomas develop from a type of glial cells called astrocytes. Astrocytes are star shaped cells. They support the nerve cells (neurones) in the brain.

 Diagram of an astrocyte - type of glial cell

Some astrocytomas are very localised (focal). This means it is easy to see the border between the tumour and the normal brain tissue on a scan or during surgery.

Other astrocytomas are called diffuse. They don’t have a clear boundary between the tumour and the normal brain tissue.

Types of astrocytomas

Astrocytomas can be low grade (slow growing) or high grade (fast growing). There are 4 main types:

Low grade

  • pilocytic astrocytoma (grade 1)
  • diffuse astrocytoma (grade 2)

High grade

  • anaplastic astrocytoma (grade 3)
  • glioblastoma (grade 4)
The most common type of astrocytoma in adults is glioblastoma.

How common it is

Astrocytomas are the most common type of brain tumours. Around 34 out of every 100 brain tumours (34%) diagnosed in England between 2006 and 2010 were astrocytomas.

Around 80 out of every 100 astrocytomas (80%) diagnosed every year are grade 4 (glioblastoma).

What tests will I have?

You have tests to diagnose an astrocytoma. Your doctor checks the size of the tumour and its location. This helps your doctor plan your treatment. The tests you might have include:

  • MRI scan or CT scan
  • a test of your neurological system (neurological examination)
  • blood tests
  • a biopsy


Your treatment depends on whether the astrocytoma is low grade (slow growing) or high grade (fast growing). It also depends on whether you have changes (mutations) in certain genes.

Treatment for low grade astrocytoma

Surgery is the main treatment for low grade astrocytomas. A highly specialised doctor (neurosurgeon) removes as much of the tumour as possible. Some neurosurgeons might suggest that you are awake for the whole or part of the operation. This is called awake craniotomy.

But it isn’t always possible to completely remove the tumour in some parts of the brain. But even when some tumour if left behind, low grade tumours may take years to cause symptoms again. 

Radiotherapy uses high energy x-rays to destroy cancer cells. Your doctor might recommend that you have radiotherapy after surgery if you:

  • are over 40 years old
  • have a lot of tumour left behind after surgery

Treatment for high grade astrocytoma (including glioblastoma)

Surgery is the main treatment for high grade astrocytomas. A specialist doctor called neurosurgeon removes as much of the tumour as possible. Some neurosurgeons might suggest that you are awake for the whole or part of the operation (awake craniotomy).

In some specialist centres, your neurosurgeon may use an MRI scan and a laser system to destroy the brain tumour. But this treatment isn’t suitable or is available to everyone.

Radiotherapy uses high energy x-rays to destroy cancer cells. You might have radiotherapy if you are well overall and able to care for yourself.  

You might take a chemotherapy drug called temozolomide if you are well and able to care for yourself. You usually have temozolomide for several months. You might have temozolomide:

  • after surgery and radiotherapy if you have a grade 3 astrocytoma
  • at the same time as radiotherapy (chemoradiotherapy) if you have glioblastoma

Treatment for a high grade astrocytoma can control the tumour for some time. But the tumour can start to grow again. If this happens, you might have:

  • the chemotherapy combination PCV or lomustine
  • more surgery
  • more radiotherapy

Follow up

You have regular appointments with your doctor or nurse after treatment finishes. Your doctor examines you at each appointment. They ask how you are feeling, whether you have had any symptoms or side effects, and if you are worried about anything. You might also have MRI scans on some visits.

How often you have check ups depend on your individual situation.

For a grade 1 astrocytoma, you might have an MRI scan every 1 to 3 years.

For a grade 2, 3 or 4 astrocytoma, you might have an MRI scan every 3 to 6 months, for two years. You then have an MRI scan every 6 months or every year.

Coping with astrocytoma

Coping with a diagnosis of a brain tumour can be difficult, both practically and emotionally. It can be especially difficult when you have a high grade tumour. Being well informed about the type of tumour you have, and its treatment can make it easier to cope.  

Research and clinical trials

Doctors are always trying to improve the diagnosis and treatment of brain tumours. As part of your treatment, your doctor might ask you to take part in a clinical trial. This might be to test a new treatment or look at different combinations of existing treatments.

Last reviewed: 
30 Oct 2019
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