Postoperative radiotherapy and chemotherapy in the management of oligodendroglioma: single institutional review of 88 patients.

We retrospectively evaluate the prognostic factors affecting the local control, survival and the potential role of chemotherapy in the management of patients with oligodendroglioma. The medical records of 88 patients treated by postoperative external beam radiotherapy +/- chemotherapy at our institution between December 1993 and December 2002 were analyzed. Nine patients (10%) were treated with an accelerated fractionation scheme, while 79 patients were treated with conventional doses. The median RT dose was 54.8 +/- 2.58 Gy for low-grade tumors, and 58.7 +/- 2.46 Gy for high-grade tumors. PCV chemotherapy regimen was given to 18 patients; temozolamide was administered in three patients. Chemotherapy was not given concomitantly in any patients. The median follow-up was 56 months (range 7-134 months). The 5-year overall and progression-free survival rates for entire group were 86% and 79%, respectively. Patients with epilepsy at presentation had better 5-year overall survival (93% vs. 74%, P=0.04). High grade tumors had significantly lower overall survival rate. Age, presence of motor deficit at diagnosis and histological grade were found have a significant impact on progression-free survival. The 5-year overall and progression free survival rates of patients with high-grade tumors were 69%, 51% and 74%, 68% for chemotherapy and no-chemotherapy group, respectively (P=0.9 for OS, P=0.3 for PFS). In multivariate analysis no significant factor affecting the overall survival and progression-free survival was found. Chemotherapy given after postoperative radiotherapy in patients with oligodendroglioma did not improve survival in this retrospective study.