NIMG-84. TUMOR LOCATION IS PROGNOSTIC FOR OVERALL SURVIVAL IN NEWLY DIAGNOSED GLIOBLASTOMA: EVIDENCE FROM 1,458 PATIENTS POOLED FROM INTERNATIONAL TRIALS, SINGLE INSTITUTION DATABASES, AND MULTICENTER CONSORTIUMS

Abstract

The prognostic significance of tumor location in newly diagnosed GBM (NDGBM) remains provocative and poorly understood. In this study we pooled imaging data in >1,400 NDGBM patients from international multicenter clinical trials, single institution databases, and multicenter clinical trial consortiums to identify relationships between tumor location on OS, independent of clinical and genetic or molecular characteristics. METHODS: Data from 1,458 newly diagnosed GBM patients from the following sources were included in our imaging database: 1) a single institution database from UCLA (N=398; Training Set 1); 2) patients treated within the Ben and Cathy Ivy Foundation for Early Phase Clinical Trials Consortium (N=262; Training Set 2); and 3) AVAglio - an international phase III trial comparing chemoradiation plus bevacizumab (N=404) vs. placebo (N=394) used as a validation set. Voxel-wise statistical parameter mapping (SPM) using multivariate Cox regression was performed to determine the influence of tumor location on OS. Covariates included in the SPM model consisted of clinical variables (age, gender, etc.), MGMT status, molecular phenotype (when available), initial treatment including extent of resection, and RPA class. Separate maps were created for all three datasets independently (UCLA, Ivy, and AVAglio) to validate the reproducibility of the SPMs. RESULTS: Data suggest tumors localized to the left or right parietal lobe, left insula, left or right thalamus, and left frontal lobe have an elevated hazard ratio (HR>1.5, P<0.05), whereas tumors localized to the right frontal lobe or left or right anterior cingulate had a significantly lower risk of death (HR<0.8, P<0.05), independent of other covariates. Frontal lobe and anterior cingulate regions were associated with the proneural molecular subtype and younger patients, and mesenchymal tumors and tumors in older patients were localized more posterior. CONCLUSION: Results from the current study further support the hypotheses that tumor location significantly influences survival in patients with NDGBM.