Survival trends of oligodendroglial tumor patients and associated clinical practice patterns: a SEER-based analysis

There is limited information on the management strategies and survival trends for oligodendroglioma patients. Here we used the Surveillance, Epidemiology and End Results (SEER, 1999–2012) database to analyze the historical trends of oligodendroglioma patient survival and correlate these trends to evolving clinical practice of radiation therapy (RT) use and surgical practice of gross total resection (GTR). We identified 2689 World Health Organization (WHO) grade II oligodendroglioma (abbreviated as O2) and 1191 WHO grade III oligodendroglioma (abbreviated as O3). Time-trend analyses were performed for overall survival, radiation treatment (RT) use, and extent of surgical resection (EOR). In multivariable Cox models that accounted for age, race, sex, tumor size, tumor location, EOR, and RT status, the hazard of dying from O3 has significantly decreased over the study period (p < 0.01), while the hazard of dying from O2 has remained largely unchanged. A search of the published literature revealed articles reporting results largely supportive of these observations. The pattern of surgical practice and RT for O3 patients remained unchanged throughout the study period, suggesting that the survival improvement may be related to evolving patterns of medical management. Results from the SEER database indicate significant gains have been made in survival for O3 patients between 1999 and 2012. Such gains were not observed for O2 patients during this study period.