Integrated MRI-Immune-Genomic Features Enclose a Risk Stratification Model in Patients Affected by Glioblastoma.

Background: The aim of the present study was to dissect the clinical outcome of GB patients through the integration of molecular, immunophenotypic and MR imaging features.
Methods: We enrolled 57 histologically proven and molecularly tested GB patients (5.3% IDH-1 mutant). Two-Dimensional Free ROI on the Biggest Enhancing Tumoral Diameter (TDFRBETD) acquired by MRI sequences were used to perform a manual evaluation of multiple quantitative variables, among which we selected: SD Fluid Attenuated Inversion Recovery (FLAIR), SD and mean Apparent Diffusion Coefficient (ADC). Characterization of the Tumor Immune Microenvironment (TIME) involved the immunohistochemical analysis of PD-L1, and number and distribution of CD3+, CD4+, CD8+ Tumor Infiltrating Lymphocytes (TILs) and CD163+ Tumor Associated Macrophages (TAMs), focusing on immune-vascular localization. Genetic, MR imaging and TIME descriptors were correlated with overall survival (OS).
Results: MGMT methylation was associated with a significantly prolonged OS (median OS = 20 months), while no impact of p53 and EGFR status was apparent. GB cases with high mean ADC at MRI, indicative of low cellularity and soft consistency, exhibited increased OS (median OS = 24 months). PD-L1 and the overall number of TILs and CD163+TAMs had a marginal impact on patient outcome. Conversely, the density of vascular-associated (V) CD4+ lymphocytes emerged as the most significant prognostic factor (median OS = 23 months in V-CD4 ^high vs. 13 months in V-CD4 ^low , p = 0.015). High V-CD4+TILs also characterized TIME of MGMT ^meth GB, while p53 ^mut appeared to condition a desert immune background. When individual genetic (MGMT ^unmeth ), MR imaging (mean ADC ^low ) and TIME (V-CD4+TILs ^low ) negative predictors were combined, median OS was 21 months (95% CI, 0-47.37) in patients displaying 0-1 risk factor and 13 months (95% CI 7.22-19.22) in the presence of 2-3 risk factors ( p = 0.010, HR = 3.39, 95% CI 1.26-9.09).
Conclusion: Interlacing MRI-immune-genetic features may provide highly significant risk-stratification models in GB patients.