Once a mass is identified the definitive diagnosis will be made by microscopic examination of the tumor. Chemotherapy Most oligodendrogliomas respond to some form of chemotherapy, usually in less than 3 months. Postoperative Radiation Benefits of postoperative radiation are controversial. Some studies have shown improved survival, while others have shown no increase in survival. Most oligodendrogliomas are slow-growing neoplasm.
Tumor grade is the single most important prognostic variable.