Treatment outcomes and prognostic factors of patients with supratentorial low-grade oligodendroglioma

Purpose: Oligodendroglioma is a relatively rare central nervous system tumor. Currently, surgical intervention is the mainstay of treatment, and the role of postoperative radiotherapy (RT) remains a subject of controversy. The objective of this study was to investigate the prognostic factors, evaluate the treatment outcomes, and assess whether postoperative RT has a benefit on local control and overall survival rates. Methods and Materials: This was a retrospective review of 52 consecutive adult patients with supratentorial low-grade oligodendrogliomas diagnosed at our institution between September 1980 and September 1998. Thirty-two received postoperative RT. Data were analyzed retrospectively to survey the significant prognostic factors for local control and overall survival. Results: The 5-year overall and progression-free survival rate was 80% and 67%, respectively. Twenty-five patients experienced local disease progression during the follow-up period. In multivariate analysis, postoperative RT and age at diagnosis showed independent prognostic significance for overall survival. For progression-free survival, postoperative RT was the only independent prognostic factor. Conclusion: On the basis of the results of this study, we recommend considering postoperative RT as one of the standard adjuvant treatment modalities for patients with supratentorial low-grade oligodendroglioma, regardless of the extent of surgical resection. The optimal treatment strategy to maximize the treatment outcome should still be explored.