BIOM-75. MRI Flair Signal Assessment in Neuro-Oncology (Sano) as a Measurable Timepoint for Interventional Therapy Prior to Progression in High Grade Gliomas: A Window of Opportunity

Abstract

BACKGROUND: There are no validated clinical or radiographic assessments for response to therapy in glioblastoma (GBM). Offering interventions at the time of progression using our current assessment tools is likely too late as second-line therapies have failed to significantly delay progression and extend survival. In 2020, our team was first in the US to publish the largest and most comprehensive retrospective review identifying the T2/FLAIR MRI signal assessment protocol as an early indicator of progressive GBM. We proposed that the time of FLAIR signal abnormality within the resection cavity (RC) anticipated GBM progression by nearly 4 months and if used as a timepoint for therapeutic intervention could reshape glioma clinical trial design. METHODS: To support validation of SANO, a prospective assessment of 146 GBM patients between 2019-2021 yielded 71 cases meeting resection and imaging inclusion criteria. We analyzed sequential brain MRIs from initial diagnosis to first progression for development of T2 FLAIR signal intensity (SI) within the RC as previously reported (Gatson et al 2020) and included cases with ventricle associated surgery as a comparator. PFS and OS were evaluated using Kaplan-Meier curves stratified by SI. RESULTS: Development of SI occurred in 80.3% (n=57) GBM patients on average 2.8 months before RANO-assessed progression. A faster time to progression from SI development occurred in cases with ventricle associated RC. SI-positivity again portended poorer outcomes for PFS and OS as compared to SI-negative cases. Use of the eye (globe) for FLAIR assessment, instead of the ventricles, to qualitatively discern the presence of SI in ventricle associated RC. CONCLUSIONS: This small prospective review supports our initial findings to validate a highly sensitive brain tumor imaging biomarker, SI, and should at least supplement existing response assessment criteria to improve declaration of GBM progression. Furthermore, use of SANO might also offer an earlier window of opportunity for salvage therapy intervention and offer new avenues for glioma clinical trial design.