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

The EORTC/NCIC 22981/26981 study demonstrated an improvement in median overall survival (OS) from 12.1 to 14.6 months in patients with glioblastoma (GBM) who received temozolomide with post-operative radiotherapy (RT). The current study was performed to determine if those results translated into a survival benefit in a population-based cohort. Patients diagnosed between 2000 and 2006 with a GBM who underwent surgery and post-operative RT were selected from the Surveillance, Epidemiology and End Results database. Patients were grouped into time periods: 2000–2001, 2002–2003, 2004 and 2005–2006 (which represented those treated after the EORTC/NCIC trial presentation in 2004). Relative survival (RS) was estimated by the Kaplan–Meier method, and Cox multivariable regression modeling was used to estimate proportional hazard ratios (HR). Over time, there was improvement in the median and 2-year RS of 12 months and 15% for 2000–2001, 13 months and 19% for 2002–2003, 14 months and 24% for 2004, and 15 months and 26% for 2005–2006 (P < 0.0001 compared to 2000–2001 and 2002–2003; P = 0.07 compared to 2004). The estimated adjusted HR showed that patients diagnosed in 2005–2006 had significantly improved survival when compared to patients diagnosed in 2000–2001 (HR = 0.648, 95% CI 0.604–0.696). The median and 2 year RS of 15 months and 26% 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 current treatment of glioblastoma nationwide is now associated with an improved survival compared to previous time cohorts.