Improved survival time trends for glioblastoma using the SEER 17 population-based registries.

Abstract

2013 Background: The EORTC/NCIC 22981/26981 study demonstrated a significant improvement in median overall survival (OS) from 12.1 to 14.6 months in newly diagnosed glioblastoma (GBM) who received concomitant and adjuvant temozolomide to standard post-operative radiotherapy (RT) (Stupp et al.). The current study was performed to determine if those results have translated into an OS benefit in a population-based cohort. Methods: Patients, ages 20 years and older, who had been diagnosed between January 2000 and December 2006 (follow-up through December, 2007) with a GBM in a brain or central nervous system site and who underwent surgical resection and post-operative RT were selected from the Surveillance, Epidemiology and End Results (SEER) 17 registries research database. Patients were grouped into three time periods for comparison: 2000-2001, 2002-2003, and 2005-2006 (which likely represented the group treated after the EORTC/NCIC trial initial presentation in 2004). OS was estimated by the Kaplan-Meier method, and Cox multivariable regression modeling was used to estimate proportional hazard ratios controlling for potential confounders, such as age, gender, race, extent of surgery, and SEER registry. Results: 7,022 patients were selected with a median follow up of 13 months. Of the cohort, 79.3% received a gross total resection. The median and two year OS for the entire cohort for 2000-2006 was 13 months and 20%, respectively. Over the three time periods studied, there was a significant improvement in the median and 2 year OS of 12 months and 14% for 2000-2001, 13 months and 18% for 2002-2003, and 14 months and 25% for 2005-2006 (p < 0.0001). The estimated adjusted hazard ratio showed that patients diagnosed in 2005-2006 had significantly improved OS when compared to patients diagnosed in earlier time periods (HR = 0.651 95% CI: 0.606 -0.699). Conclusions: The median and 2 year OS of 14 months and 25% in 2005-2006 was similar to the median and 2 year OS of 14.6 months and 26% seen in the EORTC/NCIC phase III study. These results are encouraging and suggest that the improved OS associated with the EORTC/NCIC regimen for GBM patients has successfully been translated to population-based settings.