A multicenter study of anaplastic oligodendroglioma: the Korean Radiation Oncology Group Study 13-12.

Although some existing evidence supports the addition of chemotherapy (CT) to radiation therapy (RT) for anaplastic oligodendroglioma treatment, controversy about both the criteria for suitable candidates and the optimal treatment schedule remains. We reviewed data from 376 newly diagnosed anaplastic oliogodendroglial tumor patients from nine Korean institutes were reviewed from 2000 to 2010. Total tumor removal was performed in 146 patients. More than 85% of the entire patients received postoperative RT, and 59% received CT. Approximately 50% (n = 189) received CT in addition to RT and 9% (n = 32) received CT only. A multivariate analysis revealed that younger age, frontal lobe location of the tumor, gross total removal, 1p/19q codeletion, and initial RT were associated with longer progression-free and overall survival rates. No difference was observed in outcomes from the treatment that included either temozolomide or PCV (procarbazine, lomustine, and vincristine) in addition to RT regardless of the 1p/19q deletion status. A clear improvement in progression-free and overall survival was observed for RT and combined CT/RT in compared with CT only. Postoperative RT appears to improve survival for entire group thus total removal and 1p/19q codeletion may not be sufficient criteria to omit RT as a treatment option. These results suggest that RT should continue to be offered as the standard treatment option for patients with anaplastic oligodendroglial tumors.