Oligodendroglioma
Oligodendrogliomas account for roughly 3% of all primary brain tumours. They are more common in adults, particularly those aged 30-50. They are usually grade 2 or grade 3. Because of this, there are various treatment methods, which we discuss here.
Short summary
Oligodendroglioma is a type of brain tumour that develops from the brain’s glial cells. It is a primary brain tumour, which means it starts in the brain rather than starting somewhere else in the body and spreading to the brain.
These tumours can be either low grade or high grade. Because of this, treatment can range from ‘watch and wait’ to neurosurgery, radiotherapy, and chemotherapy.
Oligodendroglioma symptoms usually depend on where the tumour is located in the brain, but could include:
- Seizures
- Headaches
- Altered sensations
- Muscular weakness
On this page, we’ll discuss in detail:
- What is an oligodendroglioma?
- What are the symptoms of an oligodendroglioma?
- How is an oligodendroglioma treated?
- What causes oligodendroglioma?
- How long can I live with an oligodendroglioma?
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What is an oligodendroglioma?
An oligodendroglioma is a rare type of primary brain tumour that develops from glial cells in the brain. This type of tumour is part of a group of brain tumours called gliomas.
Oligodendrogliomas make up about 3% of all primary brain tumours. They are the third most common of all gliomas.
The majority of oligodendrogliomas occur in the frontal lobe. The second most common site affected is the temporal lobe, followed by the parietal lobe.
They’re more common in adults, particularly in people aged 30-50, and are slightly more common in men than in women.
Oligodendrogliomas are described in terms of its grade :
- grade 2 oligodendrogliomas, which grow slowly
- grade 3 oligodendrogliomas, which grow faster and are more likely to spread within the brain.
What are the symptoms of an oligodendroglioma?
Oligodendrogliomas may cause any of the symptoms common among brain tumours, particularly:
- Seizures
- Headaches
- Altered sensations, like strange smells or hallucinations relating to sense of smell
- Muscular weakness, particularly down one side of the body, and loss of control of bodily movements.
Symptoms of a brain tumour depend on where it is located.
In the frontal lobe, oligodendrogliomas can cause:
- Gradual changes in mood or personality
- Speech and language issues
- Physical issues, such as weakness or numbness in the muscles on one side of the body.
If it is located in the temporal lobe, this may cause problems with:
- Speech and language
- Memory
- Seizures
How is an oligodendroglioma treated?
Grade 2 oligodendrogliomas usually grow slowly. If the tumour isn’t causing symptoms or growing quickly, yur medical team might put you on active monitoring (also called watch and wait) instead of starting treatment straight away.
If the tumour is large, causing symptoms which affect your quality of life, or is thought to be a grade 3 tumour, you may be offered surgery to remove as much of the tumour as possible. This may be followed by radiotherapy or chemotherapy.
Oligodendrogliomas are often described as diffuse, which means they can grow into surrounding brain tissue. This can make them harder to remove completely with surgery.
After surgery, a sample of the tumour is tested to confirm the diagnosis and grade. Sometimes, the results show a different type of glioma, as they can look similar on brain scans.
If the tumour is confirmed as grade 3, or if it’s growing or causing symptoms, additional treatment may be recommended with radiotherapy or chemotherapy.
There are two genetic alterations that confirm the diagnosis of an oligodendroglioma:
- A mutation in the IDH1 or IDH2 gene
- A co-deletion of parts of chromosomes 1p and 19q
These changes are found using biomarker testing, which is now essential for diagnosing oligodendrogliomas and deciding on the best treatment plan.
What is the 1p/19q test?
The co-deletion of 1p/19q confirms the diagnosis of an oligodendroglioma. If it is not present, then it may be another type of glioma.
How does the test work and what does it show?
Our bodies are made up of cells. Each cell has 23 pairs of chromosomes, which carry your genes (DNA). One chromosome of each pair is inherited from your mother, and the other from your father. Each pair of chromosomes are numbered 1 to 22, then XX or XY.
The 1p/19q test looks at genetic changes to chromosomes 1 and 19 to see whether they have a section missing. If the sections called the p section (p for “petite”, i.e. the shorter) of chromosome 1 and the q section (q has been chosen because it is the next letter in the alphabet) of chromosome 19 are missing, this means that the genes carried in those sections are also missing.
These genes seem to be involved in resistance to chemotherapy drugs. So, if you’re found to be missing both those sections, you’re more likely to have a better response to chemotherapy and longer overall survival.
What is the IDH1/IDH2 test?
This test is useful in diagnosing different types of gliomas. Your medical team needs it to confirm the diagnosis of an oligodendroglioma, and to make decisions about the most appropriate treatment for you.
It may also be useful in predicting how effective a particular treatment is likely to be.
How does the test work and what does it show?
IDH1 and IDH2 are genes in the tumours DNA – a change (mutation) in either the IDH1 or IDH2 genes is required to confirm the diagnosis of oligodendrogliomas or astrocytomas.
Medical experts call tumours that have the change IDH–mutant. These tumours have a better response to treatment.
Gliomas that do not have an IDH mutation are termed an IDH-Wildtype or IDH-Negative. These tumours may grow more quickly and have less response to treatment. The new classification system classifies these tumours as glioblastomas.
In summary, in the most up to date tumour classification system, only oligodendrogliomas and astrocytomas will have IDH mutations and all glioblastomas are IDH-wildtype.
What is the MGMT methylation test?
For people with oligodendroglioma, the MGMT methylation test helps to predict how effective chemotherapy treatment is likely to be, although there are many other factors that also affect response to treatment. Your medical team can use this to help plan a suitable, individualised treatment plan.
MGMT is a DNA repair enzyme that works to repair tumours cells. If the MGMT promotor in a tumour cell is methylated, it doesn’t work very well and therefore chemotherapy can cause more damage to the tumour cell. This can make chemotherapy more effective.
Your medical team will do the MGMT methylation on the sample of tumour after surgery.
What does the test show?
In summary, the test looks at the amount (percentage) of cells with MGMT methylation.
- Tumours that are MGMT methylated are more likely to respond well to TMZ or PCV chemotherapy.
- MGMT unmethylated tumours are less likely to respond to TMZ chemotherapy.
There are other factors that influence the effectiveness of chemotherapy, so there’ll always be ‘good’ and ‘poor’ responders in both the methylated and unmethylated groups.
TERT promoter mutation test
When found with 1p/19q co-deletion and IDH-mutant biomarkers, the TERT promoter mutation suggests a diagnosis of oligodendroglioma and predicts greater benefit from chemotherapy and radiotherapy and longer survival, particularly in grade 2 and 3 gliomas.
The TERT mutation may be found in grade 2 and 3 gliomas that don’t have mutations in the IDH1 or IDH2 genes (called IDH-wildtype). When this happens, it usually means the tumour is behaving more like a glioblastoma, which is a more aggressive type of brain tumour. This combination may mean that earlier and more intensive treatment is needed.
Tessa Jowell BRAIN MATRIX
The Tessa Jowell BRAIN MATRIX is a study which aims to improve knowledge of glioma and identify potential new treatments. Participants in the study will have their tumour tested in a lab to uncover its molecular profile.
What causes oligodendroglioma?
Medical professionals don’t know the exact cause of oligodendroglioma. This is the case with most tumours.
There is nothing that you have done to cause the development of a tumour. This can be a difficult thing to accept and can leave you feeling helpless, but there is nothing you could have done to prevent this from happening.
This can be a difficult thing to accept and can leave you feeling helpless, but there is nothing you could have done to prevent this from happening.
The Brain Tumour Charity is contributing to the funding of research into the possible causes of brain tumour development as we accelerate towards a cure.
How long can I live with an oligodendroglioma?
Oligodendrogliomas can be either grade 2 or grade 3, so the outcome can vary from person to person.
The tumour might impact you differently from others because of a lot of different factors. For example, depending on the tumour’s grade and other personal factors, like symptoms, age and the type of treatment they receive.
However, we do have information on prognosis and survival rates. To find out more, you can click through to our oligodendroglioma prognosis page.
Accurate source of health information
We follow stringent steps to make sure that our information is accurate, reliable, and up to date. Find out more about how we create trustworthy health information.
- Verified by: J Kahan – Consultant Clinical Oncologist
- Date checked: 20/04/26
- Next check: 20/04/29
Louis, D.N., Perry, A., Wesseling, P., Brat, D.J., Cree, I.A., Figarella‑Branger, D., Hawkins, C., Ng, H.K., Pfister, S.M. and Reifenberger, G. (eds.), 2021. WHO Classification of Tumours of the Central Nervous System. 5th ed. Lyon: International Agency for Research on Cancer (IARC). WHO Classification of Tumours, Volume 6.
Barrow Neurological Institute, 2024. Oligodendroglioma prognosis. Available at: https://www.barrowneuro.org/condition/oligodendroglioma/ (Accessed: 25 July 2025). (Five‑year survival for grade 3 oligodendrogliomas ranges from 30–50%)
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