Oligodendroglioma
Oligodendrogliomas are a rare type of brain tumour that develops from glial cells called oligodendrocytes. They are more common in adults than in children.
Symptoms of oligodendroglioma depend on where the tumour is in the brain. Common symptoms include headaches and seizures (fits).
What are oligodendrogliomas?
Oligodendrogliomas develop from glial cells called oligodendrocytes. These cells make a fatty white substance (myelin) that covers the nerves. Myelin helps signals (impulses) to travel along the nerves more quickly.
Oligodendrogliomas are mostly found in the frontal lobe of the cerebrum. They can also start in the spinal cord, but this is rare.
Rarely, oligodendrogliomas can spread to other parts of the brain and the spinal cord.
Doctors use a system to group (classify) brain tumours into different groups and types. The World Health Organisation (WHO) regularly update this system. The information in this page is based on the latest WHO classification of 2021.
Oligodendrogliomas are a type of brain tumour that belongs to a group of brain tumours called gliomas.
Doctors have changed the way they group and describe different gliomas. All oligodendrogliomas are now called:
- oligodendroglioma, IDH mutant and 1p/19q co-deleted
What does IDH mutant and 1p/19q co-deleted mean?
Your doctor looks to see if there are certain gene changes in the brain tumour cells. These tests are also called biomarkers or molecular studies. Your doctor uses these test results to decide what type of glioma you have.
IDH (isocitrate dehydrogenase) is a gene. Your doctor looks for permanent changes (mutations) in the IDH gene.
1p and 19q refer to chromosome 1 and chromosome 19. 1p/19q co-deleted means that:
- part of the short arm (p) of chromosome 1 is missing (deleted)
- part of the long arm (q) of chromosome 19 is missing (deleted)
Your doctor diagnoses you with an oligodendroglioma if the glioma cells:
- have changes (mutations) in the IDH gene – this is what IDH mutant means
- are missing parts of chromosome 1 and chromosome 19 – this is what 1p/19q co-deleted means
Grades of oligodendrogliomas
Oligodendrogliomas are put into groups based on how quickly they are likely to grow. This is called the grade.
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.
There are 2 grades of oligodendrogliomas:
- grade 2 (low grade), sometimes called diffuse
- grade 3 (high grade), sometimes called anaplastic
How common it is
Oligodendrogliomas are rare. About 3 out of every 100 primary brain tumours (3%) diagnosed in England between 1995 and 2017 were oligodendrogliomas.
What tests will I have?
You have tests to diagnose an oligodendroglioma. 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
biopsy - a test of your neurological system (neurological examination)
Treatment
Treatment depends on whether the oligodendroglioma is low grade (slow growing) or high grade (fast growing).
The main treatments for oligodendroglioma are:
- surgery to remove as much tumour as possible
- radiotherapy, which uses high energy x-rays to destroy cancer cells
- chemotherapy, which uses cytotoxic drugs to destroy cancer cells
Treatment for low grade oligodendroglioma
Surgery is usually the first treatment you have. The exact type of surgery you have depends on where the tumour is and how big it is. A highly specialist doctor (neurosurgeon) removes as much of the tumour as possible.
Oligodendrogliomas tend to grow into the brain tissue surrounding the tumour. This means that they don’t have a clear border between the tumour and the normal brain tissue. Not having a clear border can make it difficult to remove the tumour completely.
Your doctor might monitor you with regular MRI scans. This is called active monitoring. You might have active monitoring if your surgeon was able to remove all, or nearly all, of your grade 2 tumour.
You might not need any further treatment for a long time, sometimes years. When your scan shows your tumour has started to grow again, you might have:
- radiotherapy
- further surgery
- chemotherapy
You might have radiotherapy straight after surgery if:
- doctors can see tumour left behind after surgery
- you are over 40 years old
You might have chemotherapy before or after radiotherapy. Chemotherapy uses cytotoxic drugs to destroy cancer cells. You usually have a combination of chemotherapy drugs called PCV. It includes the drugs:
- procarbazine
- lomustine (CCNU)
- vincristine
Treatment for high grade oligodendroglioma
Surgery is the main treatment for high grade oligodendroglioma. A specialist doctor called neurosurgeon removes as much of the tumour as possible. This is called debulking.
It is not usually possible to remove all of the tumour. So your doctor might recommend you have radiotherapy and chemotherapy afterwards.
Radiotherapy uses high energy x-rays to destroy cancer cells. You might have radiotherapy after surgery if you are well overall and able to care for yourself.
Chemotherapy uses cytotoxic drugs to destroy cancer cells. You might have a combination of chemotherapy drugs called PCV before or after radiotherapy. PCV includes the drugs:
- procarbazine
- lomustine (CCNU)
- vincristine
Treatment for oligodendroglioma that comes back
Your treatment depends on what treatment you have already had. You might have a combination of:
- chemotherapy with lomustine, temozolomide or PCV
- 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 checks ups depend on your individual situation.
You might have an MRI scan every 3-6 months, for two years. You then have an MRI scan every year or every 2 years.
Coping with oligodendroglioma
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.
