Long-term trends in glioblastoma survival: Implications for historical control groups in clinical trials

Abstract

Background: Historical controls continue to be used in early-phase brain tumor trials. We aim to show that historical changes in survival trends for glioblastoma (GBM) call into question the use of noncontemporary controls. Methods: We analyzed data from 46 106 primary GBM cases from the SEER database (1998-2016). We performed trend analysis on survival outcomes (2-year survival probability, median survival, and hazard ratios) and patient characteristics (age, sex, resection extent, and treatment type). Results: In 2005-2016 (ie, the post-Stupp protocol era), fitting a parameter independently to each year, there was a demonstrable increase in median survival (R2 = 0.81, P