Oligodendroglioma

Updated: Oct 01, 2019
  • Author: ABM Salah Uddin, MD; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Overview

Background

Oligodendrogliomas (ODs) are primary glial brain tumors that are divided into grade II and anaplastic grade III tumors (World Health Organization [WHO] criteria). Typically, they have an indolent course, and patients may survive for many years after symptom onset. Their good prognosis relative to other parenchymal tumors probably stems from inherently less aggressive biological behavior and a favorable response to chemotherapy, a recently discovered finding based on genetic characteristics.

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Pathophysiology

Oligodendrogliomas arise in the cerebral hemispheres and are distributed among the frontal, parietal, temporal, and occipital lobe, in approximately a 3:2:2:1 ratio. Rarely, they can arise in the cerebellum, brain stem, and spinal cord. [1] They usually occur in the cerebral white matter and are very cellular, with uniform nuclei. They react with glial fibrillary acidic protein on immunostaining.

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Epidemiology

Frequency

The incidence of oligodendrogliomas ranges from 5–19% of all intracranial tumors. The newer studies showed incidence of oligodendrogliomas to be around 25% of all gliomas. This may be explained by the improvements in the treatment of oligodendrogliomas, prompting neuropathologists to favor the diagnosis.

Mortality/Morbidity

The morbidity and mortality profile for oligodendrogliomas is much better than for astrocytic tumors. However, it also depends on tumor location and pressure effects, as with any other intracranial lesion. The median survival from initial diagnosis of all low-grade oligodendrogliomas (LGOs) is 4–10 years, but it is only 3–4 years for anaplastic oligodendrogliomas.

Demographics

Oligodendrogliomas occur in both sexes, with a male-to-female predominance of 2:1.

Oligodendrogliomas may be diagnosed at any age but occur most commonly in young and middle-aged adults, with a median age at diagnosis of 40–50 years. In children, only 6% of gliomas are diagnosed as oligodendrogliomas.

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Prognosis

Combined loss of 1p/19q is a significant predictor of overall survival in anaplastic oligodendroglioma and is also significantly associated with longer recurrence-free survival and chemosensitivity. [2]

The phosphatase and tensin homologue deleted by chromosome 10 (PTEN) alteration is associated with a poor prognosis.

Other variables, including age of the patient at time of diagnosis, location and extent of surgical resection, postoperative performance status, histologic features of the tumor, and use of adjuvant therapies and early presentation with seizures, determine the prognosis for an individual patient. Overall, as many as three fourths of patients with nonanaplastic tumors can be expected to survive 5 years from the time of diagnosis, with a median reported survival duration of 6-10 years. For those with anaplastic oligodendrogliomas, median survival is more likely to be 3–4 years. Late progression of disease is common, so the usual 5-year survival time used to indicate "cure" in other cancers is not relevant for oligodendrogliomas.

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