High-grade glioma

This information page will tell you about primary malignant brain tumours known as high-grade gliomas. You can download and print a pdf copy of this information.

High-grade gliomas may also be called malignant brain tumours or brain cancer. They are also given specific names, such as glioblastoma multiforme (GBM), high-grade oligodendroglioma or high-grade astrocytoma.

Please note: Our information on high-grade gliomas will help you talk with your doctor or medical team about your condition. It should not be used as a substitute for professional care.

What is a primary high-grade glioma?

Brain tumours are made up of abnormal cells in the brain. Primary brain tumours are made up of abnormal cells that come from the brain itself. These are different to secondary brain tumours, which arise in the brain due to cancer elsewhere in the body.

Tumours are graded on a scale from 1 to 4 according to how malignant they are i.e. how fast they grow and how likely they are to spread. This is in accordance with the World Health Organisation (WHO) classification system for brain tumours. Cells from the brain are examined under a microscope and are graded according to how abnormal they look. The more abnormal the cells look, the higher the grade; the higher the grade, the higher the malignancy. High-grade primary brain tumours are graded 3 or 4 and are malignant.

Malignant tumours can sometimes spread to other parts of the brain. Generally speaking, malignant means that the tumour:

• is relatively fast growing, and cannot be cured.
• may come back after surgery even if completely removed; it can never be considered to be completely removed.
• may spread to other parts of the brain or spinal cord.
• cannot be treated with surgery alone and will need further treatments, such as radiotherapy or chemotherapy, to try to control the growth.

Over half of all primary brain tumours are glioma tumours or gliomas, so called because they develop from cells called glial cells. Glial cells support the nerve cells of the brain. Gliomas are more common in adults although they can occur in children. Older people are more susceptible to high-grade gliomas, and they tend to affect men more than women.

In summary: primary high-grade gliomas are formed from glial cells within the brain. They are graded 3 or 4 and are therefore classed as malignant.

Types of high-grade glioma

There are three main types of high-grade gliomas which are named according to the specific type of cell they most closely resemble:

• Ependymomas – these develop from ependymal cells which line the cavities in the brain. They can be high-grade or low-grade.
• Oligodendrogliomas – these develop from cells called oligodendrocytes which produce fatty coverings to insulate the nerves. Oligodendrogliomas are most commonly found in the forebrain that is in the temporal or frontal lobes. The tumour can spread within the central nervous system via the fluid that circulates round the brain and spinal cord. (This fluid is called cerebrospinal fluid or CSF.)
• Astrocytomas – these develop from star-shaped cells called astrocytes which are thought to provide the brain’s framework and help to control the chemistry of the brain cells.

You can also get mixed glioma tumours which are made up of a mixture of some of these cell types.

Astrocytomas are the most common type of glioma and there are two different types of high-grade astrocytoma tumours which are defined by their grade:

• Anaplastic astrocytoma – this is a grade 3 astrocytoma.
• Glioblastoma multiforme – this is a grade 4 astrocytoma and is also known as a GBM or GBM4.

Where are high-grade gliomas located?

High-grade gliomas may be found either above or below a membrane in the brain called the tentorium. The tentorium separates the cerebrum above from the cerebellum below.

What is the cause of high-grade gliomas?

Unfortunately the cause of high-grade gliomas remains unknown. There do not appear to be any links with occupation, infections or head injury and research has not proved a hereditary link. Visit our research section for information on projects funded by Brain Tumour UK.

What are the common symptoms?

The symptoms will be different for each person and will depend on how big and where the tumour is. Some people may experience all, some or none of the symptoms.

A high-grade glioma can commonly cause:

• headaches
• nausea and vomiting
• seizures

Other symptoms may include:

• speech problems
• problems with vision
• weakness in one or more limbs
• confusion and memory problems

Specific symptoms may arise depending on the specific location of the tumour. For example, a high-grade glioma located in the optic nerve can cause visual loss and spinal cord gliomas can cause pain, weakness or numbness in the limbs.

High-grade gliomas do not spread via the bloodstream to outside the brain. However, they can spread via the cerebrospinal fluid to produce tumours, known as ‘drop metastases’ in the spinal cord, although this is not very common.

How is a high-grade glioma diagnosed?

If doctors think you may have a brain tumour, you will have to undergo a neurological examination, i.e. performing examination and tests to check the nervous system (brain, spinal cord and nerves). The doctor may also want you to have one or more of the following tests:

• CT (Computed Tomography) brain scan is a specialised X-ray which is used to take pictures of the brain and takes about 10 to 20 minutes.
• MRI (Magnetic Resonance Imaging) brain scan uses magnetism instead of X-rays to give very clear pictures of the brain, showing the location and size of the tumour. It usually takes about 30 to 40 minutes. People with pacemakers cannot have this test and those with any other metallic implant should inform the medical team well before the test.

What treatments might be available?

The treatment you receive will depend on the type and size of glioma, where it is located within the brain and what grade and therefore how malignant it is. Treatment will also depend on your general health.

Often treatment is a combined approach, using surgery, radiotherapy and chemotherapy. Your medical team will plan your treatment with you.

The different treatment options which are currently available are shown below. Research is ongoing to find more effective treatments for high-grade gliomas; new treatments may become available and you can discuss these with your doctor.

Surgery

This will be considered if the tumour is in a place that can be operated on without a high risk of causing severe damage.

High-grade gliomas may occur in places in the brain that are not easily reached. In these instances, a very small piece of the tumour, called a biopsy sample, may be taken using surgical techniques. This biopsy sample will then be tested in a laboratory to diagnose the type of tumour.

Tumours that are located in the areas of the brain that control breathing, intellect or physical movement may be considered too risky to operate on.

Radiotherapy

This treatment uses high energy X-rays to destroy tumour cells. It is often given after surgery and may be used alone or with chemotherapy. Visit our section on radiotherapy.

Chemotherapy

This uses drugs to destroy tumour cells. It may be given alone or with surgery and/or radiotherapy. Visit our section on chemotherapy.

For high-grade gliomas, the following types of chemotherapy may be used:

• Temodal (also known as temozolomide)
  Temodal cannot cure a brain tumour, but may extend survival and improve the quality of life of the patient. It is type of drug known as an alkylating agent and it works by stopping cancer cells from making new DNA. If they cannot make DNA, they cannot split into two new cancer cells and therefore the tumour cannot grow.
  Newly diagnosed gliomas are often treated with a combination of radiotherapy and Temodal.
• Carmustine or Gliadal wafers
  Carmustine is a chemotherapy drug and is an alkylating agent like Temodal. Carmustine is available as gel wafers, also called Gliadal wafers, which can be implanted directly into the brain. They are used for newly diagnosed high-grade gliomas and may be placed into the brain after surgery or in combination with radiotherapy.

No treatment

The tumour may be considered to be too large to operate on. Or the tumour may be in a place in the brain that is very important and therefore it is too risky for surgery or treatment to be performed. Or there may be another reason, perhaps based on medical risk. In these cases, it may be decided that the most appropriate treatment is to offer the best supportive care.

Version 1.1 January 2012 - Review date: January 2015

References

The following references were consulted during the writing of this leaflet:

SB Tatter, ‘The new WHO Classification of Tumors affecting the Central Nervous System’ (accessed January 2012).

NHS: Malignant brain tumour (cancerous) (accessed December 2011).

Macmillan Cancer Help: Mixed gliomas (accessed December 2011).

PubMed Health: Brain tumor – primary – adults (accessed December 2011).

Cancer Help UK: Carmustine (BCNU, Gliadel) (accessed December 2011).

Lin SH, Kleinberg KR, Carmustine wafers: localized delivery of chemotherapeutic agents in CNS malignancies. Expert Rev Anticancer Ther 2008; 8: 343-59.

Schneider T, Mawrin C, Scherlock C, Skalej M, Firsching R. Gliomas in adults. Dtsch Arztebl Int 2010; 107: 799-808.

Burton EC, Prados MD. Malignant gliomas. Curr Treat Options Oncol. 2000; 1: 459-68.

Mulholland PJ, Thirlwell C, Brock CS, Newlands ES. Emerging targeted treatments for malignant glioma. Expert Opin Emerg Drugs. 2005;10: 845-54.

Further sources of information

We've worked with the NHS to put more information and videos about high grade gliomas on NHS Choices.