Oligodendrogliomas treatment

Patients who have oligodendrogliomas (WHO grade II) generally have better prognoses than do patients who have diffuse astrocytomas. In particular, patients who have oligodendrogliomas with 1p/19q codeletion have a much longer survival.[3] Most of the oligodendrogliomas eventually progress.

Treatment options for oligodendrogliomas include:

Controversy exists concerning the timing of radiation therapy after surgery. A study (EORTC-22845) of 300 patients with low-grade gliomas who had surgery and were randomly assigned to either radiation therapy or watchful waiting, did not show a difference in OS between the two groups.[1][Level of evidence A1] For more information, see the Low-grade tumors section.

For low-grade (WHO grade II) tumors that are considered high risk, radiation therapy followed by six cycles of PCV chemotherapy is a recommended option based on the long-term follow-up results of RTOG-9802, a randomized trial for high-risk, low-grade gliomas.[3][Level of evidence A1] Notably, RTOG-9802 enrolled patients with a variety of tumors, including astrocytomas, oligodendrogliomas, and mixed oligoastrocytomas. In a retrospective subset analysis, only the oligodendroglial tumors appeared to benefit from the addition of PCV.[4] For more information, see the Diffuse astrocytomas treatment section.

The discovery of the IDH1 and IDH2 variants, which are independent prognostic factors for significantly improved survival in diffuse gliomas, has greatly helped to identify patients with high-risk disease. For more information, see the Diffuse astrocytomas treatment section. In addition, a high proportion of WHO grade II oligodendrogliomas have 1p/19q codeletion, which is a powerful prognostic factor for improved survival.[19-21] Therefore, the presence of IDH1 and IDH2 variants and 1p/19q codeletion should be included in the assessment of high risk. Molecular correlative data from the RTOG-9802 trial, which would be informative about which patients benefited most from the addition of PCV, have not been reported.