Oligodendroglioma Treatment & Management

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

Individualize treatment of an oligodendroglioma depending on the presence or absence of symptoms, location and biological aggressiveness of the tumor, extent of possible surgical resection, and histopathology and degree of anaplasia. Treatment options vary from conservative treatment of some patients with serial imaging studies and no intervention to aggressive multimodal treatment including surgical resection, radiotherapy, and chemotherapy in others. Because most patients either develop or present with seizures, anticonvulsive therapy is recommended once the patient is diagnosed with oligodendroglioma. See Brain Cancer Treatment Protocols for summarized information.


The role of chemotherapy for the treatment of oligodendroglioma was well established by several studies using nitrosourea-based therapy.{re8} Most used procarbazine, lomustine (CCNU), and vincristine, a combination chemotherapy regimen (ie, PCV) developed by Levin and coworkers. [9] Patients with pure and mixed oligoastrocytic tumors, newly diagnosed, and recurrent mixed tumors responded to this therapy before receiving radiotherapy. Despite prolonged responses, most patients experience disease relapse and ultimately die of progressive disease. The median time for recurrence was at least 16 months in partial responders and at least 25 months in complete responders. Recurrent tumors are not cured by PCV, and the intensity of treatment may be limited by the bone marrow reserve. [10]

Several studies have evaluated the role of temozolomide as second-line chemotherapy for recurrent oligodendroglioma and showed a response rate of about 25% for patients relapsing after PCV therapy. The EORTC study evaluated temozolomide as a first-line chemotherapy for recurrent oligodendroglial tumors and showed a response rate of 54%, with 39% of patients remaining free from progression at 12 months. [11]

An interim analysis of a phase II study of intensified chemotherapy (I-PCV) alone for newly diagnosed anaplastic oligodendroglioma showed that median progression-free survival for all patients is 19.5 months, similar to the median progression-free survival for patients receiving radiotherapy alone in the RTOG and EORTC trials. These findings suggest that the patient care is not compromised by initiating treatment with chemotherapy alone and delay of radiotherapy may have a beneficial impact on quality of life. [12]

A phase III study preliminary findings reported by Cairncross et al, comparing radiation therapy versus chemotherapy plus radiation in patients with newly diagnosed anaplastic OD and mixed OD, showed overall similar survival in both groups (4.8 y for radiotherapy plus chemotherapy group vs 4.5 y for radiotherapy alone). However, disease progression-free interval was longer for the combined therapy group (2.6 y vs 1.9 y for radiotherapy alone group). [13]

New agents are needed for further improvements of survival in OD.

Radiation therapy

Various studies compared the effects of radiation therapy before and after the maximal surgical resection. The studies showed that the immediate postoperative irradiation in patients with LOG increases the median progression-free survival by 2 years without affecting the overall survival. This result suggests that radiation therapy can be withheld until a clinical or radiologic progression occurs to delay the sequelae of cranial irradiation.

The RTOG study compared the effects of pre–radiation therapy dose-intensified PCV chemotherapy followed by radiation therapy versus radiation therapy alone in newly diagnosed oligodendroglioma and anaplastic oligodendroglioma. No difference in overall survival was noted. However, the progression-free survival rate was longer after radiation therapy plus PCV.

Shaw et al found that for oligodendroglioma patients with 2-year survival (more benign tumors), the probability of overall survival for an additional 5 years was 74% with combination therapy compared to 59% with radiotherapy alone. [14]

One study suggests that patients with oligodendroglioma are at higher risk of developing radiation necrosis (RN). Of the cohort of 319 patients, 41 patients were identified as having RN (12.9%): 28 patients (21.3%) with oligodendroglioma and 13 (6.9%) with astrocytoma (HR 3.42, p <  0.001). Patients with oligodendroglioma who received > 54 Gy had a higher incidence (31.2%) than those receiving ≤ 54 Gy (14.3%, HR 6.9, p = 0.002). [15]  


Surgical Care

Historically, surgery has been the mainstay of treatment for oligodendrogliomas. The extent of resection depends in large part on the location of the tumor and its proximity to "eloquent" brain areas. If possible, the goal is total resection of the tumor. In patients who undergo total gross resection, no further treatment may be necessary, but the patient must be followed up for clinical or radiologic recurrence.

The optimal use of radiotherapy in the treatment of oligodendroglioma is not entirely clear. Although differences of opinion exist regarding the efficacy of radiotherapy for oligodendrogliomas, radiation is used routinely at diagnosis in patients who have undergone incomplete removal of nonanaplastic oligodendrogliomas and generally is recommended for patients with anaplastic oligodendrogliomas regardless of the extent of resection. Radiotherapy also is used at recurrence in previously untreated patients. As systemic therapies are becoming available and more effective, delaying radiotherapy in many patients may be prudent to avoid the toxic side effects of radiation to the nervous system.