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Anaplastic oligodendrogliomas treatment
Source: Central Nervous System Tumors Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: March 28, 2025 · Captured 2026-09-09.
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Context: Treatment of Primary CNS Tumors by Tumor Type / Oligodendroglial Tumors Treatment
Patients with anaplastic oligodendrogliomas (WHO grade III) have a low cure rate with standard local treatment, but their prognoses are generally better than those of patients with anaplastic astrocytomas. Prognoses are particularly better for patients with 1p/19q codeletion, which occurs in most of these tumors. Two phase III randomized trials restricted to patients with anaplastic gliomas (NCT00626990 and NCT00887146) are active. However, efficacy data are not yet available. For more information, see the Anaplastic astrocytomas treatment section. These patients are appropriate candidates for clinical trials designed to improve local control by adding newer forms of treatment.
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Information about ongoing clinical trials is available from the NCI website.
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Treatment options for anaplastic oligodendrogliomas include:
Surgery plus radiation therapy with or without chemotherapy.[22]
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Evidence (surgery followed by radiation therapy with or without chemotherapy):
Mature results from the EORTC Brain Tumor Group Study 26951 (NCT00002840), a phase III randomized study with 11.7 years of follow-up, demonstrated increased OS and PFS in patients with anaplastic oligodendroglial tumors with six cycles of adjuvant PCV chemotherapy after radiation therapy, compared with radiation therapy alone.[23][Level of evidence A1]
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Mature results from the EORTC Brain Tumor Group Study 26951 (NCT00002840), a phase III randomized study with 11.7 years of follow-up, demonstrated increased OS and PFS in patients with anaplastic oligodendroglial tumors with six cycles of adjuvant PCV chemotherapy after radiation therapy, compared with radiation therapy alone.[23][Level of evidence A1]
OS was significantly longer in the radiation therapy and PCV arm (42.3 months vs. 30.6 months; HR, 0.75; 95% CI, 0.60–0.95).
Mature results from the EORTC Brain Tumor Group Study 26951 (NCT00002840), a phase III randomized study with 11.7 years of follow-up, demonstrated increased OS and PFS in patients with anaplastic oligodendroglial tumors with six cycles of adjuvant PCV chemotherapy after radiation therapy, compared with radiation therapy alone.[23][Level of evidence A1]
Patients with 1p/19q-codeleted tumors derived more benefit from adjuvant PCV chemotherapy than did those with non–1p/19q-deleted tumors.[23]
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In contrast, the RTOG trial (RTOG-9402 [NCT00002569]) demonstrated no differences in median survival by treatment arm between an 8-week, intensive PCV chemotherapy regimen followed by immediate involved-field-plus-radiation therapy and radiation therapy alone.[24]
In contrast, the RTOG trial (RTOG-9402 [NCT00002569]) demonstrated no differences in median survival by treatment arm between an 8-week, intensive PCV chemotherapy regimen followed by immediate involved-field-plus-radiation therapy and radiation therapy alone.[24]
In an unplanned subgroup analysis, patients with 1p/19q-codeleted anaplastic oligodendrogliomas and mixed anaplastic astrocytomas demonstrated a median survival of 14.7 years versus 7.3 years (HR, 0.59; 95% CI, 0.37–0.95; P = .03).
In contrast, the RTOG trial (RTOG-9402 [NCT00002569]) demonstrated no differences in median survival by treatment arm between an 8-week, intensive PCV chemotherapy regimen followed by immediate involved-field-plus-radiation therapy and radiation therapy alone.[24]
For patients with non-codeleted tumors, there was no difference in median survival by treatment arm (2.6 vs. 2.7 years; HR, 0.85; 95% CI, 0.58–1.23; P = .39).[24][Level of evidence A1]
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Postoperative radiation therapy alone has been compared with postoperative chemotherapy alone in patients with anaplastic gliomas (including 144 astrocytomas, 91 oligoastrocytomas, and 39 oligodendrogliomas) with crossover to the other modality at the time of tumor progression. Of the 139 patients randomly assigned to undergo radiation therapy, 135 were randomly assigned to receive chemotherapy, with a 32-week course of either PCV or single-agent temozolomide (2:1:1 randomization).[12][Levels of evidence A1 and B1]
Postoperative radiation therapy alone has been compared with postoperative chemotherapy alone in patients with anaplastic gliomas (including 144 astrocytomas, 91 oligoastrocytomas, and 39 oligodendrogliomas) with crossover to the other modality at the time of tumor progression. Of the 139 patients randomly assigned to undergo radiation therapy, 135 were randomly assigned to receive chemotherapy, with a 32-week course of either PCV or single-agent temozolomide (2:1:1 randomization).[12][Levels of evidence A1 and B1]
TTF or OS did not differ across the treatment arms and were not affected by the order of the modalities.
Based on these data, CODEL (NCT00887146), a study that randomly assigned patients to receive radiation therapy alone (control arm), radiation therapy with temozolomide, and temozolomide alone (exploratory arm), was halted because radiation therapy alone was no longer considered adequate treatment in patients with anaplastic oligodendroglioma with 1p/19q-codeletions.[25] Temozolomide and PCV chemotherapy in anaplastic oligodendroglioma have not been compared, although in the setting of grade III anaplastic gliomas, no survival difference was seen between PCV chemotherapy and temozolomide.[12,26]
The combination of radiation and chemotherapy is not known to be superior in outcome to sequential modality therapy.
A high proportion of anaplastic oligodendrogliomas have IDH1 andIDH2 variants and 1p/19q codeletion, both powerful prognostic factors for improved survival. For more information, see the Diffuse astrocytomas treatment section.[23,24] In addition, PCV chemotherapy has been shown to be predictive in a retrospective analysis of the phase III trials described earlier. Therefore, assessment of these molecular markers may aid management decisions for anaplastic oligodendrogliomas.
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