NCOG-27. STATUS AS A CLINICAL TRIAL PARTICIPANT AND OUTCOME IN IDH-WILDTYPE GLIOBLASTOMA

Abstract

Abstract INTRODUCTION Standard of care for glioblastoma consists of surgery, followed by combined chemoradiation and adjuvant chemotherapy, as per the seminal EORTC study from 2005. Clinical trial patients, being a population selected for functional status, hepatic function, renal function, and lack of other malignancies, may have improved outcome over the general treated population. METHOD Single center retrospective analysis of status as a clinical trial patient in the upfront setting and other clinical factors/biomarkers, analyzed for correlation with outcomes (PFS/OS) in IDH-wildtype glioblastomas. RESULTS 82 patients with IDH-wildtype glioblastoma were identified between 2014 and 2020, treated with standard of care or with an upfront clinical study (43% women; median age 66 years, range 35-91 years of age). 22 patients (27%) were treated with upfront clinical study. Status as a patient treated in an upfront clinical study did not correlate with outcome (hazard ratio HR PFS 0.99, CI 0.57-1.7, p=0.97; HR OS 1.09, CI 0.56-2.1, p=0.81). Frontal lobe was most frequently involved (n=36, 44%), followed by parietal lobe (n=33, 40%). Age was not a strong predictor of survival (R2 0.01). No statistically significant correlation was observed between outcome and laterality or location. MGMT promoter methylation was associated with improved PFS (HR 0.56, CI 0.33-0.94, p=0.03) and OS (HR 0.40, CI 0.19-0.85, p=0.02), with mPFS 6 months vs 9 months and mOS 16 months vs 20 months (unmethylated vs methylated respectively). CONCLUSION In this retrospective cohort of IDH-wildtype glioblastomas, age, tumor laterality, and tumor location were not significant predictors of outcome. MGMT promoter methylation predicted for superior PFS/OS. Patient selection for clinical studies are influenced by entry criteria, however at least in this retrospective review, status as a clinical study patient in the upfront setting did not correlate with outcome compared to patients treated with upfront standard of care.