Oligodendroglioma

Oligodendrogliomas are a type of glioma that starts in glial cells called oligodendrocytes. Oligodendrocytes are cells that cover and protect nerves.

All oligodendrogliomas have a chromosome abnormality where the “p” arm of chromosome 1 and the “q” arm of chromosome 19 have been deleted.

Oligodendroglioma sometimes spreads to the cerebrospinal fluid but rarely spreads outside the brain or spinal cord.

Based on the World Health Organization (WHO) grading system, oligodendrogliomas are classified as low grade (grade 2) or high grade (grade 3).

Low-grade oligodendrogliomas are grade 2 tumours. They are slow growing and may be present for many years before they are diagnosed. These tumours can become more aggressive over time. People with oligodendrogliomas may have a long history of seizures. Oligodendrogliomas are most often found in people between the ages of 50 and 60.

The following are treatments for low-grade oligodendrogliomas:

Surgery may be done to remove all of the tumour or as much of the tumour as possible.

Active surveillance with regular MRI scans may be done to watch for growth of the tumour if it can’t be completely removed with surgery.

Radiation therapy may be given after surgery if the tumour can’t be completely removed or if it regrows after surgery and radiation therapy was not given previously.

Chemotherapy may be given after surgery, usually with radiation therapy, if the tumour can’t be completely removed. It may also be used to treat tumours that have come back after treatment (called recurrent low-grade oligodendrogliomas).

The most common chemotherapy drug used is temozolomide (Temodal).

The most common chemotherapy drug combination used is PCV, which is procarbazine (Matulane), lomustine (CeeNU, CCNU) and vincristine (Oncovin).

Anaplastic oligodendrogliomas are high-grade tumours. Anaplastic oligodendrogliomas usually grow quickly. Tumours may develop in one place or in many places throughout the brain.

The following are treatments for anaplastic oligodendrogliomas.

Surgery may be done to remove all of the tumour or as much of the tumour as possible followed by radiation therapy, with or without chemotherapy.

Radiation therapy is usually given after surgery. It may also be given as the main treatment if surgery can’t be done.

Chemotherapy is given after surgery, usually with radiation therapy. It may also be used to treat tumours that have come back after treatment (called recurrent anaplastic oligodendrogliomas).

The most common chemotherapy drug used is temozolomide.

The most common chemotherapy drug combination used is PCV (procarbazine, lomustine and vincristine).

Other medicines used for people with brain tumours do not treat the tumour but help treat symptoms caused by the tumour or the treatments.

• Corticosteroids help lessen the swelling around the brain tumour and may relieve headaches and other symptoms. A commonly used corticosteroid is dexamethasone (Decadron, Dexasone).
• Antiseizure medicines are given to prevent seizures. They are usually not given unless the tumour has caused seizures. A commonly used antiseizure drug is phenytoin (Dilantin).

Some clinical trials in Canada are open to people with oligodendroglioma. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.