Tumour Group: Glioma
WHO Grade: Oligoastrocytomas (grade II) are considered low-grade tumours. They generally grow at a slower rate than anaplastic oligoastrocytomas (grade III), which are malignant.

Oligoastrocytomas may evolve over time into anaplastic oligoastrocytomas.

Prevalence/Incidence: Approx. 40% of primary brain tumours are gliomas. Mixed gliomas, primarily oligoastrocytomas, account for 5-10% of gliomas and 1%  of all brain tumours.
Typical Age Range: Oligoastrocytomas develop in young and middle-aged adults (ages 30 to 50). Very few children are diagnosed with oligoastrocytoma.

Description of Tumour
Treatment / Standard of Care

Description of Tumour

Oligoastrocytomas belong to a group of brain tumours called gliomas. Gliomas are tumours that come from the glial, or supportive, cells of the brain. There are several different types of gliomas. An oligoastrocytoma is a “mixed glioma” tumour, which contains both abnormal oligodendroglioma and astrocytoma cells.

These tumours can be found anywhere within the cerebral hemispheres of the brain, although the frontal and temporal lobes are the most common locations.


Common symptoms include, but are not necessarily limited to:

  • Seizures
  • Headaches
  • Personality changes

Treatment / Standard of Care

If the tumour is accessible, standard treatment for oligoastrocytoma is surgical removal of as much of the tumour tissue as possible. Following surgery, treatment options can depend on the molecular profile. In selected patients observation may be appropriate, for others chemotherapy alone and in patients with aggressive physical and biological factors then radiation with or without chemotherapy may be required.


A prognosis is an estimate of the likely progress of a disease after a diagnosis, based on an average patient group. Since every person is different, please take time to talk with your health care team about how this information applies to you.

By clicking on 'Expand,' a statistic on the prognosis for oligoastrocytoma will be shown.

Expand for Prognosis Information

For brain tumour patients, a prognosis depends on several factors, which can include age and other health issues, the size of the tumour, its molecular profile, the type of tumour, how much can be removed and its response to treatments such as chemotherapy and radiation therapy.

When your doctor talks with you about prognosis, he/she will take into account your age, the location of the tumour, grade of the tumour cells, whether your tumour has deletions of 1p and 19q, and the amount of tumour removed during surgery. Oligoastrocytoma growth generally depends on the percent of astrocytoma in the tumour, as astrocytomas tend to grow more rapidly than oligodendrogliomas.


Adult Brain Tumour Handbook 6th Edition. Brain Tumour Foundation of Canada. 2012.

Louis, David N. WHO Classification of Tumours of the Central Nervous System. Lyon: International Agency for Research on Cancer, 2007. Print

"Oligoastrocytoma." Www.abta.org. American Brain Tumour Association, n.d. Web. 11 July 2013.

Image credited to http://radiopaedia.org/articles/oligoastrocytoma


You can also download this information as a Information Sheet on Oligoastrocytoma (pdf).


Gary Evjen was living a happy and healthy life with his wife, Karen. But by early 2005, Gary’s health had changed markedly. Over the next year, Gary would experience mood changes, and memory and speech problems. In April 2006, Gary was diagnosed with a grade III anaplastic oligoastrocytoma. Today, Gary and Karen organize the Saskatoon Brain Tumour Support Group and make it a priority to raise awareness about the disease.

Read Gary and Karen's inspiring story >>


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