What is Oligodendroglioma?
Oligodendrogliomas are primary central nervous system tumours that arise from cells of the oligodendroglial lineage. Oligodendrocytes are glial cells that produce myelin, which insulates nerve fibres and enables faster nerve signal transmission in the brain.
Oligodendrogliomas most commonly arise in the frontal lobes within the white matter of the brain and show diffuse infiltration into surrounding tissue. Lower-grade oligodendrogliomas (WHO grade 2) are slow-growing tumours that may progress to higher-grade disease over time as additional genetic changes accumulate.
Oligodendrogliomas are characterised by the combined loss of the short (p) arm of chromosome 1 and the long (q) arm of chromosome 19, known as the 1p/19q co-deletion. Tumours with this co-deletion generally respond well to radiotherapy and chemotherapy and are associated with a more favourable prognosis compared with other diffuse gliomas.
Another hallmark of oligodendroglioma is a mutation in the isocitrate dehydrogenase genes (IDH1 and IDH2). In current World Health Organization (WHO) diagnostic criteria, the presence of both an IDH mutation and 1p/19q co-deletion defines oligodendroglioma.
Oligodendrogliomas predominantly affect young adults however they may also occur in younger patients.
Oligodendroglioma Symptoms
Like many other brain tumours, symptoms of oligodendroglioma may not appear until the tumour grows large enough to disrupt normal brain function. The most common symptom is seizures, which occur in approximately 60–80% of patients.
Symptoms primarily depend on the tumour’s location. Because oligodendrogliomas commonly arise in the cerebral hemispheres, particularly the frontal lobes, tumours in these areas may affect functions such as speech, movement, thinking, and behaviour.
Some of the symptoms you may experience include:
- Weakness or reduced movement, often affecting one side of the body (hemiparesis)
- Difficulty speaking or understanding others (aphasia)
- Vision changes such as blurred vision or visual field loss
- Memory problems
- Difficulty thinking or concentrating
How Is Oligodendroglioma Diagnosed?
Diagnosis usually begins with neurological assessment and brain imaging. A CT scan may be used initially when patients present with sudden neurological symptoms, mainly to rule out urgent conditions such as bleeding or stroke. However, MRI is the main imaging test used because it provides more detailed information about tumour location, size, and infiltration.
Advanced MRI techniques may help doctors better characterise the tumour and assess features that may suggest tumour grade. Functional MRI and other advanced imaging modalities can help identify critical brain regions involved in speech or movement, which can assist surgeons in planning treatment.
Surgery plays a crucial role in the diagnosis of oligodendroglioma because it allows doctors to obtain tumour tissue for detailed histological and molecular testing. Removing tumour tissue may also help relieve symptoms caused by tumour growth. Histopathological and molecular analysis are essential for diagnosis. Under current WHO criteria, a tumour must contain both an IDH mutation and a 1p/19q co-deletion to be classified as oligodendroglioma.
Tumours that lack this molecular profile are classified as other types of diffuse glioma. In particular, paediatric tumours that resemble oligodendroglioma under the microscope often represent biologically different tumour types.
Grade 2 vs Grade 3 Oligodendroglioma
Oligodendroglial tumours are classified into two grades according to the World Health Organization (WHO) classification: grade 2 (low-grade) oligodendroglioma and grade 3 or anaplastic (high-grade) oligodendroglioma.
Grade 3 oligodendrogliomas generally have a worse prognosis than grade 2 tumours and may develop when a lower-grade tumour acquires additional genetic alterations over time. Histologically, grade 3 tumours differ significantly from grade 2 tumours, showing more aggressive features such as increased cell division, microvascular proliferation, and sometimes necrosis.
Oligodendroglioma Treatment and Options
Treatment for oligodendroglioma usually involves a combination of surgery, radiotherapy, and chemotherapy, although the exact approach depends on tumour grade, symptoms, and patient factors. Initial treatment usually involves maximal surgical resection to remove as much tumour as safely possible. Depending on the tumour grade, symptoms, and risk factors, additional treatment such as radiotherapy and chemotherapy may be recommended after surgery. However, tumour location near important brain regions can make surgical removal more challenging.
If oligodendroglioma returns after treatment, options may include additional surgery, radiotherapy, chemotherapy or participation in clinical trials.
Because oligodendrogliomas carry a genetic change called the 1p/19q co-deletion, these tumours tend to respond well to certain chemotherapy treatments. The standard of care for high-risk (especially grade 3) tumours is radiation with PCV (procarbazine, lomustine, vincristine). Temozolomide (TMZ) is frequently used as a more tolerable alternative, particularly in lower-grade (grade 2) cases, although PCV has shown superior, longer-term progression-free survival (PFS) in some studies.
While PCV has demonstrated improved overall survival in patients with 1p/19q co-deleted oligodendroglioma, it can cause significant side effects. Because PCV can be difficult to tolerate, temozolomide is sometimes used as an alternative treatment, although ongoing studies continue to compare these approaches.
Oligodendroglioma Prognosis and Survival Rate
Oligodendroglioma is a serious but treatable tumour that generally responds well to therapy. Oligodendrogliomas carrying both a 1p/19q co-deletion and an IDH mutation generally have a better prognosis than many other diffuse gliomas, including astrocytomas. Survival may exceed 10 years, although this varies depending on factors such as tumour grade, patient age, treatment approach and the extent of tumour removal during surgery.
Younger patients often tolerate treatment better and may experience fewer treatment-related complications than older patients. Patients who undergo more extensive tumour removal generally have better outcomes compared to those who have partial resection. However, the feasibility of complete resection depends on the tumour’s location and whether surgeons can remove it safely without damaging nearby critical structures.
Prognosis also depends on tumour grade. WHO grade 2 oligodendrogliomas typically grow more slowly and are associated with longer overall survival. In contrast, grade 3 (anaplastic) oligodendrogliomas are more aggressive and fast-growing, and associated with shorter survival than grade 2 tumours.
Living With Oligodendroglioma
People living with oligodendroglioma may experience physical symptoms that persist beyond during or after treatment. These ongoing symptoms can be distressing and can affect quality of life. Symptoms related to tumour growth, including seizures, headaches, and cognitive changes, can affect day-to-day functioning and may require medical treatment and supportive care.
While medications can help relieve symptoms such as headaches, nausea, fatigue, and seizures, lifestyle strategies, such as proper nutrition, regular physical activity, stress management strategies, meditation, and adequate sleep, may help support overall wellbeing.
In addition to tumour-related symptoms, treatment can also reduce quality of life. Surgery can also have a negative impact and may result in neurocognitive or motor deficits that require rehabilitation and adjustment.
Although modern radiotherapy techniques are designed to offer greater precision and better protection of surrounding healthy tissue, patients may still experience short-term side effects such as fatigue, nausea, headaches, or skin irritation. Chemotherapy may also cause side effects such as fatigue, nausea, lowered blood counts, or increased infection risk.
Support groups and counselling can play an important role in helping individuals cope with these challenges, offering emotional support and practical guidance to navigate life after an oligodendroglioma diagnosis and treatment.
Oligodendroglioma Clinical Trials and Research Advances
In some patients with grade 2 IDH-mutant gliomas who have residual tumour after surgery but few symptoms, targeted therapies such as the IDH inhibitor vorasidenib are being studied to delay the need for radiotherapy or chemotherapy. This approach aims to delay treatments such as radiotherapy or chemotherapy, which can sometimes cause long-term side effects.
In contrast, grade 3 oligodendroglioma typically requires a multimodal treatment approach, including surgery, radiotherapy, and chemotherapy. Chemotherapy options commonly include the PCV regimen (procarbazine, lomustine, and vincristine), which has shown survival benefits, or temozolomide, which is often easier to administer and generally better tolerated.
Cure Brain Cancer Foundation is committed to supporting innovation and funding breakthroughs in neuro-oncology. Explore the research we’re funding, including the work of Dr. Olga Zaytseva, that are helping to drive the breakthroughs of tomorrow.
Support for families and carers
While oligodendroglioma is often slower-growing than stage 4 brain cancers, it can still be debilitating and life-limiting. The physical, emotional, and cognitive impacts of the tumour and its treatment can affect every aspect of daily life for both patients and their families.
Support is available through the National Advocacy Service, who can assist with accessing initiatives like NDIS to support you and your family following a diagnosis.
Visit our Support Hub for more information.
Disclaimer: All Cure Brain Cancer Foundation website content is created and published online for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. You should seek your own medical advice from your doctor or other qualified health professionals.
References
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- 1p/19q Co-deletion in Glioma: ESMO Biomarker Factsheet | OncologyPRO