EMBR-14. INFLUENCE OF MRI FEATURES ON THE SURVIVAL AND IMPACT ON INDIVIDUAL MOLECULAR SUBGROUPS: RESULT FROM 171 PATIENTS WITH MEDULLOBLASTOMA

BACKGROUND: To investigate the influence of different MRI features on survival in patients with medulloblastoma. METHODS: A total of 171 patients were included in the study, including 131 pediatric and 40 adults (> 18 years). A set of 16 pre-defined semantic MRI features was analyzed using T1W (pre and post-contrast), T2W, and diffusion-weighted imaging (additional sequences as available). Patients with a definitive event (recurrence) or a minimum follow up of 12 months (in case of no recurrence) were included in the current analysis. All patients were treated and followed up according to standard institutional practice. Log-rank test was used for univariate analysis (UVA) and Cox regression for multivariate analysis (MVA). RESULTS: The molecular subgroups were as follows: WNT-27 children, 7 adults; SHH-31 children, 29 adults; group 3–32 children, 3 adults; and group 4–41 children, 1 adult. The median follow up was 45 months (range 1 to 137 months). For all the patients, on UVA the recurrence-free survival (RFS) was significantly (p<0.05) influenced by location-vertical, brainstem involvement, contrast uptake area, contrast heterogeneity, necrosis, and calcification. Similar factors (T2W homogeneity instead of area of contrast) impacted overall survival (OS). On MVA, location-vertical, brainstem involvement, and calcification were significant features for both RFS and OS. Tumor location-vertical was the only feature influencing RFS and OS within the SHH subgroup. For group 3 tumors, contrast uptake area (RFS and OS) and calcification (RFS alone) had a significant influence (MVA). Within group 4, contrast pattern (RFS) and T2W homogeneity (RFS and OS) were significant factors on UVA, none on MVA. CONCLUSION: Several MRI features can be linked with survival in patients with medulloblastoma, with a specific impact on individual molecular subgroups. Considering the entire population, non-central location on the vertical aspect, tumors away from brainstem, calcification are risk factors associated with inferior outcomes.