An oligodendroglioma is a type of brain tumour. This information is about oligodendrogliomas, their symptoms and treatments. It should ideally be read with our general information about brain tumours.
The central nervous system (CNS) is made up of the brain and spinal cord. Cells in the CNS normally grow in an orderly and controlled way. If for some reason this order is disrupted, the cells continue to divide and forma lump or tumour.
A tumour is either benign or malignant. Benign tumours can continue to grow but the cells do not spread from the original site. In a malignant tumour, the cells can invade and destroy surrounding tissue and may spreadto other parts of the brain.
Within the brain there are nerve cells, and cells that support and protect the nerve cells. The supporting cells are called glial cells. A tumour of these is known as a glioma.
Oligodendroglioma is a type of glioma that develops from cells called oligodendrocytes. These cells produce the fatty covering of nerve cells. This type of tumour is normally found in the cerebrum (the white area on the diagram above), particularly in the frontal or temporal lobes.
Oligodendrogliomas are divided into two types:
A well-differentiated tumour, which grows slowly.
An anaplastic oligodendroglioma, which grows more quickly.
Tumours affecting the central nervous system (CNS) are fairly rare. Each year about 4,700 people in the UK are diagnosed with tumours of the CNS. Around 1 in 20 (5%) of these are oligodendrogliomas. This type oftumour is more common in adults, but it can occur in children.
Grading of oligodendrogliomas
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Grading refers to the appearance of the tumour under a microscope. The grade gives an idea of how quickly the tumour may grow. Grade 2 is low-grade and grade 3 is high-grade (anaplastic). There is no grade 1.
Causes of oligodendrogliomas
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As with most brain tumours, the cause of these tumours is unknown. Research is being carried out into possible causes.
Signs and symptoms of an oligodendroglioma
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People with slow-growing oligodendrogliomas may have mild symptoms for several years before the tumour is discovered.
The first symptoms of any type of brain tumour are usually due to increased pressure within the skull (raised intracranial pressure). This may be caused by a blockage in the ventricles (fluid-filled spaces of the brain),which leads to a build-up of cerebrospinal fluid (CSF). CSF is the fluid that surrounds the brain and the spinal cord. This increased pressure may also be caused by swelling around the tumour itself.
Raised intracranial pressure can cause headaches, sickness (vomiting) and visual problems. Fits (seizures) and changes in behaviour and personality can also be general signs of a brain tumour.
Oligodendrogliomas can grow in different parts of the brain, and symptoms may relate to the area of the brain that is affected:
A tumour in the frontal lobe of the brain may cause gradual changes in mood and personality. There may also be paralysis (inability to move) on one side of the body. This is called hemiparesis.
A tumour in the temporal lobe of the brain may cause problems with coordination and speech, and it may affect your memory.
Tests and investigations for oligodendrogliomas
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Your doctors need to find out as much as possible about the type, position and size of the tumour, so they can plan your treatment. You may have a number of tests and investigations.
The doctor will examine you thoroughly and test the power and feeling in your arms and legs. They will also test your reflexes.
Your doctor will look into the back of your eyes using an ophthalmoscope. They can see if the optic nerve at the back of the eye is swollen. This can be caused by oedema (swelling of the tissues within the brain),which may occur due to an increase in the amount of fluid in the brain.
A CT scan or MRI scan will be done to find the exact position and size of the tumour.
CT (computerised tomography) scan
A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. The scan is painless and takes 10-30 minutes. CT scans use small amounts of radiation, which will be very unlikely to harm you or anyone you come into contact with.
You will be given an injection of a dye, which allows particular areas to be seen more clearly. For a few minutes, this may make you feel hot all over. If you are allergic to iodine or have asthma you could have a more serious reaction to the injection, so it’s important to let your doctor know beforehand.
MRI (magnetic resonance imaging) scan
This test is similar to a CT scan but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. Before the scan you may be asked to complete and sign a checklist. This is to make sure it’s safe for you to have an MRI scan.
Before having the scan, you’ll be asked to remove any metal belongings including jewellery. Some people are given an injection of dye into a vein in the arm. This is called a contrast medium and can help the images from the scan show up more clearly. During the test you will be asked to lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you’ll be given earplugs or headphones.
To give an exact diagnosis, a sample of cells from the tumour (biopsy) is sometimes taken, and then looked at under a microscope. The biopsy will also show if the tumour is slow- or fast-growing. The biopsy involves an operation. Your doctor will discuss whether a biopsy is necessary in your case, and what the operation involves.
Treatment for an oligodendroglioma
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The treatment for oligodendroglioma depends on a number of things including your general health, the size and position of the tumour, and whether it has spread to surrounding areas. The results of your tests will enable your doctor to discuss your treatment plan with you
Your treatment will usually be planned by a team of specialists known as a multidisciplinary team (MDT). The team will usually include a:
doctor who operates on the brain (neurosurgeon)
doctor who specialises in treating illnesses of the brain (neurologist)
doctor who specialises in treating brain tumours (an oncologist)
specialist nurse and possibly other healthcare professionals, such as a physiotherapist or dietitian.
There are some risks associated with treatment to the brain - your doctor will discuss these with you.
If the pressure in the skull is raised, it’s important to reduce it before any treatment is given for brain tumours. Steroid drugs may be used to reduce swelling around the tumour. If raised intracranial pressure is due to a build-up of CSF, a tube (shunt) may be inserted to drain off the excess fluid.
Where possible, surgery is the main treatment for an oligodendroglioma. The aim of surgery is to remove as much of the tumour as possible without damaging the surrounding brain tissue. Depending on the size and position of the tumour, it may not be possible to remove it completely and further treatment may be given after surgery.
Some tumours cannot be reached by surgery, or the risk of damage to the rest of the brain may be too high. If surgery is not possible, your doctor will discuss other types of treatment with you.
Radiotherapy treatment uses high energy rays to destroy cancer cells and is often used after surgery. The aim of the radiotherapy is to destroy any remaining malignant cells. It may be used on its own to treat anoligodendroglioma if surgery is not possible.
Radiotherapy is usually given as an external treatment, but occasionally it may be given in the form of radioactive implants (small radioactive metal objects that are inserted into the tumour during an operation).
Chemotherapy is the use of anti-cancer (cytotoxic) drugs destroy cancer cells. It may be given alone to treat oligodendroglioma, or with surgery and/or radiotherapy.
Medicines and seizures
If you experience a seizure you may be given a medicine called an anticonvulsant to help prevent them.
You may find the idea of a tumour affecting your brain extremely frightening. You may experience many emotions, including anxiety, anger and fear. These are all normal reactions and are part of the process many people go through in trying to come to terms with their condition.
Many people find it helpful to talk things over with their doctor or nurse, or with one of our cancer support specialists. Family members and close friends can also offer support.
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In some circumstances, you may not be allowed to drive for a period of time. If you have had an epileptic fit, the Drivers and Vehicle Licensing Association (DVLA) will not allow you to drive for a year after your last fit. You can then drive again provided you remain well.
You will not be able to drive after treatment for at least one to two years, depending on the grade of your tumour. If the tumour comes back, however, this period will be extended.
You may not be allowed to drive some types of vehicle, such as an LGV (large goods vehicle) or a PCV (passenger carrying vehicle).
The hospital will not contact the DVLA. It is your responsibility to do so and your doctor will advise you how to go about this. You can contact the DVLA by phone on 0300 790 6806 or at dvla.gov.uk.
Drivers and Vehicle Licensing Association (DVLA)
The DVLA advises GPs and other members of the medical profession on the medical standards of fitness to drive. Patients should seek advice from their doctors.
This section has been compiled using information from a number of reliable sources, including:
Levin. Cancer in the Nervous System. 2nd edition. 2002. Oxford University Press.
Raghavan, et al. The Textbook of Uncommon Cancers. 3rd edition. 2006. Wiley.
Souhami, et al. Oxford Textbook of Oncology. 2nd edition. 2002. Oxford University Press.
Tonn, et al. Neuro-oncology of CNS Tumours. 2006. Springer.
Thanks to Dr Catherine McBain, Consultant Clinical Oncologist, and the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.