Survival benefit of concomitant chemoradiation in adult supratentorial primary glioblastoma. A propensity score weighted population-based analysis

BACKGROUND: This population study aims to assess the impact of the implementation of the original Stupp protocol on overall survival in patients with new-diagnosed supratentorial primary GBM. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to study the survival of histologically confirmed adult supratentorial GBM patients diagnosed between 1998 and 2016. Kaplan-Meier, and a univariate and propensity-score weighted multivariate Cox proportional hazard model adjusted for age at diagnosis, sex, race, marital status and extent of resection was used to assess the survival of patients prior to implementation of the Stupp protocol in 2005 (Pre-Stupp) and following implementation of the Stupp Protocol until 2016 (Post Stupp). RESULTS: Overall, 6390 patients satisfied inclusion exclusion criteria. Median survival times were 13 months for the Pre-Stupp and 15 months for Post-Stupp groups (P<0.001). The 1-, 2-, 5- and 10-year survival rates for the Pre-Stupp group were 51%, 18%, 5% and 2% respectively compared to 59%, 27%, 8% and 4% on the Post-Stupp group. Propensity-score weighted analysis showed a lower mortality risk for patients who underwent concomitant chemoradiation during the Post-Stupp era (HR=0.77, 95% CI 0.62-0.94). There was a 42% relative reduction in the risk of death for patients treated during the Post-Stupp era. CONCLUSIONS: This population-based propensity-score study with long-term follow-up suggests that the implementation of the Stupp protocol in 2005 had a positive impact on the survival of patients with supratentorial GBM. This "real-world" analysis validates the results of the original randomized control trial on which this protocol is based.