Types
Glioblastomas develop from glial cells. Glial cells are the supporting cells of the brain and the spinal cord. There are different types of glial cells. These include astrocytes and oligodendrocytes.
Read about glial cells and the different parts of the brain
Doctors use a system to group (classify) brain tumours into different groups and types. The World Health Organisation (WHO) regularly updates this system. The information on this page is based on the current WHO classification, 5th edition, 2021.
Doctors have changed the way they group and describe gliomas. They used to call glioblastomas ‘glioblastoma multiforme’ (GBM). Glioblastomas are now called:
glioblastoma, IDH wildtype
Your doctor looks to see if there are certain gene changes in the brain tumour cells. These tests are also called biomarker tests. One of the genes they look at is called IDH (isocitrate dehydrogenase).
Finding out whether the IDH gene has changed helps doctors diagnose the type of glioma and understand how it might behave. Your type of glioma depends on:
the type of glial cell where the tumour started
whether there are changes in certain genes, such as the IDH gene
Your doctor may diagnose:
astrocytoma, IDH mutant - if the tumour cells have a change (mutation) in the IDH gene
glioblastoma, IDH wildtype - if the tumour cells do not have a change in the IDH gene. Wildtype means the gene has not changed.
This page is about glioblastoma, IDH wildtype.
Gliomas are also put into groups according to how quickly they are likely to grow. These are called grades.
The grade depends on how the cells look under the microscope. Generally, the more normal the cells look, the lower the grade. The more abnormal the cells look, the higher the grade. Grade also depends on genes and proteins in the tumour cells.
Glioblastomas are grade 4 tumours. This means they are fast growing, cancerous brain tumours.
Find out more about grades of brain tumours
Glioblastomas are the most common type of high grade primary brain tumour in adults. Around 32 out of every 100 primary brain tumours (around 32%) diagnosed in England between 1995 and 2017 were glioblastomas.
These statistics are based on people diagnosed using older WHO classification systems. The WHO system for grouping (classifying) the different types of brain tumours was updated in 2021. These changes might affect these figures.
The symptoms you have depend on the size of the tumour and where it is in the brain.
Symptoms can include:
headaches
feeling or being sick
seizures (fits)
difficulty walking or balancing
problems with your eyesight, such as blurred vision
feeling very tired
changes in your personality or behaviour
difficulty speaking
difficulty remembering words, or finding the right words
You have tests to diagnose glioblastoma. Your doctor checks the size of the tumour and its location. This helps your doctor plan your treatment. The tests you might have include:
or
a test of your neurological system (neurological examination)
A specialist doctor (pathologist) will do an MGMT methylation test. MGMT is a protein (enzyme) which can repair DNA damage caused by chemotherapy. This stops the treatment from working.
In some tumour cells, the MGMT gene is turned off because of a DNA change known as methylation. If it is turned off (methylated), this prevents the repair of any DNA damage. This means chemotherapy is more likely to work better.
The MGMT methylation test finds out if your tumour cells are:
methylated (high MGMT activity) – this means you might benefit from chemotherapy
non methylated or unmethylated (low MGMT activity) – this means you might not benefit from chemotherapy
Your doctor may also test for changes in other genes, such as TERT. These tests can give doctors more information about the tumour and how it may behave.
We have more information about the tests you might have to diagnose a brain tumour
The main treatments for glioblastoma are:
surgery
radiotherapy, which uses high energy x-rays to destroy cancer cells
chemotherapy, which uses cytotoxic drugs to destroy cancer cells
You might have these treatments on their own, or as a combination of treatments. You might also have supportive treatments to help with your symptoms.
Your treatment plan depends on:
your surgery and how much tumour the surgeon removed
how well you are – doctors call this your performance status
biomarker tests – for example, MGMT methylation test
Surgery is the main treatment for glioblastoma. Even if your surgeon doesn't think they can completely remove the brain tumour, they will usually try to remove as much as possible. This can help to slow down the growth of the tumour and relieve your symptoms.
It isn’t always possible to have surgery. It will depend on where the tumour is in your brain. It will also depend on whether you are well enough to have surgery.
We have more information about surgery for brain tumours
You usually have radiotherapy after surgery. You might have it with chemotherapy.
You might also have a chemotherapy drug called temozolomide. This is a tablet that you take. You have it if you are well and able to care for yourself. You have temozolomide in . You might have temozolomide:
after surgery and radiotherapy (adjuvant chemotherapy)
at the same time as radiotherapy (chemoradiotherapy) – doctors sometimes call this concomitant therapy
We have more information about temozolomide and other types of chemotherapy for brain tumours
Your healthcare team will talk to you about supportive treatments to help control your symptoms. You can have these treatments alongside surgery, chemotherapy or radiotherapy.
You might not be well enough to have treatments such as surgery or chemotherapy. Your doctor will talk to you about supportive treatments to:
help control seizures (fits)
reduce the swelling inside your brain
relieve headaches
help you stay as comfortable as possible
Read about controlling symptoms of a brain tumour
Treatment for glioblastoma can control the tumour for some time. When the tumour starts to grow again you usually have more tests. Your treatment depends on several factors including:
what treatment you had before and when you had it
your symptoms
where the tumour is
You might have:
more surgery
more radiotherapy
more of the same chemotherapy, or a different sort of chemotherapy - this is called second line chemotherapy. You might have a combination of chemotherapy drugs called PCV (Procarbazine, lomustine, and vincristine). Or CCNU (lomustine) on its own
treatment on a clinical trial
supportive care treatments
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.
Find out about the latest UK research and how you can take part in a clinical trial
A brain tumour can affect your ability to drive. You may not be allowed to drive for some time after your diagnosis or treatment.
Ask your doctor or specialist nurse how your brain tumour might affect your right to drive.
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.
You might have an MRI scan every 3 to 6 months.
Read about follow up for brain tumours
Coping with a diagnosis of a brain tumour can be difficult, both practically and emotionally. It can be especially difficult when you have a fast growing tumour. Being well informed about the type of tumour you have, and its treatment can make it easier to cope.
Find out what you can do, who can help and how to cope with a brain tumour
Last reviewed: 24 Aug 2026
Next review due: 24 Aug 2029
Primary brain tumours are tumours that start in the brain. They can start anywhere in the brain and there are many different types of tumours.
Common symptoms of brain tumours include headaches, feeling or being sick and seizures (fits).
The grade of a brain tumour gives doctors an idea of how fast or slow the tumour might grow.
Treatment for a brain or spinal cord tumour depends on the type of tumour you have, where it is and your general health.
It can be difficult to find out that you have a brain tumour. There is practical and emotional support available to help you, your family and your friends cope with a brain or spinal cord tumour.
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