Abstract
BACKGROUND: Brain-mapping scans are routinely conducted in patients with dominant frontal or temporal lesions to identify language activation areas (LAAs) prior to surgery. Post-operative radiation may also impact these functional regions. While the cognitive decline induced by radiation is well documented, the specific effects of surgical resection followed by radiation on LAAs and language-related white matter pathways remain inadequately studied. METHODS: We conducted a retrospective analysis of demographic, clinical, and imaging data from 17 patients who underwent at least two brain-mapping scans at Sheba Medical Center between 2012 and 2025. We identified functional regions, including Broca’s and Wernicke’s areas and the arcuate fasciculus. We documented tumor volumes and geometries, and compared the Lateralization Index (LI) of language activation and the Fractional Anisotropy (FA) values of the arcuate fasciculus between pre- and post-treatment scans. RESULTS: The median age-at-diagnosis was 41 (range: 4-64), and the median overall survival was 89 months (range: 19-130). Surgical resection was performed in 13 patients, including five with high-grade gliomas. The mean radiation dose was 57.5 Gy (range: 40.1-60), and the mean conformality index was 0.83 (range: 0.75-0.94). Eight patients underwent tumor resection and subsequent radiation between brain-mapping scans, with median intervals of 29 months (range: 1-110) and 26 months (range: 10-102) between radiation and the second scan. In six patients with language mapping, surgical resection and radiation significantly altered LAA laterality (p=0.044). FA values of the arcuate fasciculus showed measurable post-treatment change. CONCLUSIONS: These results suggest that surgical resection followed by radiation may significantly impact language network lateralization and white matter integrity, indicating a compensatory response to post-treatment brain injury. These findings necessitate validation in larger, prospective studies but support the integration of functional brain-imaging into radiation planning to safeguard critical language pathways, underscoring the importance of preserving these structures during treatment, similar to the maximal protection sought during tumor resection.