Oligodendroglioma

Oligodendroglioma is a rare primary brain tumor that arises from oligodendrocytes, the cells responsible for producing myelin (the protective insulation around nerve fibers) in the central nervous system. It is classified as a diffuse glioma and most commonly occurs in the cerebral hemispheres, particularly the frontal and temporal lobes. According to the WHO Classification of Tumors of the Central Nervous System, oligodendrogliomas are now defined by the presence of both IDH1 or IDH2 gene mutations and codeletion of chromosomal arms 1p and 19q (1p/19q codeletion). They are graded as either WHO grade 2 (oligodendroglioma) or WHO grade 3 (anaplastic oligodendroglioma). The most common presenting symptom is seizures, which occur in a large proportion of patients. Other symptoms depend on tumor location and may include headaches, cognitive changes, personality or behavioral alterations, weakness on one side of the body, speech difficulties, and visual disturbances. Symptoms often develop gradually over months to years, as these tumors tend to be slow-growing, particularly the grade 2 form. Some patients may be asymptomatic at diagnosis, with the tumor discovered incidentally on brain imaging. Treatment typically involves a combination of surgery, radiation therapy, and chemotherapy. Maximal safe surgical resection is generally the first step. For grade 2 tumors with favorable prognostic features, observation after surgery may be considered, while higher-risk grade 2 and all grade 3 tumors usually receive adjuvant radiation therapy and chemotherapy. The PCV regimen (procarbazine, lomustine, and vincristine) and temozolomide are the most commonly used chemotherapy options. Oligodendrogliomas with 1p/19q codeletion are notably chemosensitive and carry a significantly better prognosis compared to other diffuse gliomas. Median survival for grade 2 oligodendroglioma can exceed 10-15 years, while anaplastic oligodendroglioma has a median survival of approximately 10 years or more with appropriate treatment.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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