10010- NI-1 QUANTITATIVE ANALYSIS OF RECURRENCE PATTERNS AND DIRECTIONALITY IN PRIMARY GLIOBLASTOMA USING LESION MAPS & TRACTOGRAPHY

Abstract INTRODUCTION Identifying the sites of recurrence in primary glioblastoma is crucial for developing aggressive initial treatments. This study focuses on glioblastoma originating in the frontal lobe, hypothesizing that “recurrence progression is related to nerve fiber trajectories.” We quantitatively examined recurrence patterns. METHODS We analyzed 30 cases of primary glioblastoma in the frontal lobe treated at our institution with confirmed recurrences. For each patient, primary and recurrent lesion localizations were delineated using contrast-enhanced MRI and transformed to standard brain coordinates. This visualized the localization of lesions and allowed quantitative analysis of distribution changes. Additionally, virtual fiber tracking using DTI data from healthy subjects was performed with the primary lesion as a seed, and the correlation between the direction of recurrence and nerve fibers was analyzed using Pearson’s correlation coefficient. RESULTS Primary lesions were distributed in the MNI space across the frontal lobe, white matter, insula, putamen, thalamus, parietal lobe, temporal lobe, occipital lobe, and cerebellum at frequencies of 65.8%, 12.5%, 5.7%, 4.8%, 3.6%, 4.9%, 2.7%, 0.0%, and 0.0%, respectively. Recurrent lesions were distributed at 59.9%, 9.7%, 5.7%, 5.8%, 1.0%, 12.1%, 4.0%, 1.4%, and 0.3%, respectively. The changes in lesion distribution were statistically significant (p<0.001, Chi-square test), and post hoc Fisher’s test showed a tendency for increased occurrence in the parietal lobe (P=0.065). Recurrent lesion vectors significantly correlated with nerve fiber vectors (mean absolute correlation: 0.60, p<0.00001). CONCLUSION Primary glioblastomas in the frontal lobe tend to progress towards the parietal lobe, influenced by nerve fiber trajectories. These findings suggest that considering the direction of lesion progression could be essential in developing initial treatment strategies for glioblastoma.