AUTHOR=Gómez Vecchio Tomás , Neimantaite Alice , Corell Alba , Bartek Jiri , Jensdottir Margret , Reinertsen Ingerid , Solheim Ole , Jakola Asgeir S. 

TITLE=Lower-Grade Gliomas: An Epidemiological Voxel-Based Analysis of Location and Proximity to Eloquent Regions

JOURNAL=Frontiers in Oncology

VOLUME=Volume 11 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.748229

DOI=10.3389/fonc.2021.748229

ISSN=2234-943X

ABSTRACT=BACKGROUND: Glioma is the most common intra-axial tumor and its location relative to critical areas of the brain is important for treatment decision making. Studies often report tumor location based on anatomical taxonomy alone since estimation of eloquent regions requires considerable knowledge of functional neuroanatomy and is to some degree a subjective measure. An unbiased and reproducible method to determine tumor location and eloquence is desirable, both for clinical use and for research purposes. 
OBJECTIVE: To report on a voxel-based method for assessing anatomical distribution and proximity to eloquent regions in diffuse lower-grade gliomas (World Health Organization grade 2 and 3).
METHODS: A multi-institutional population-based dataset of adult patients (≥18 years) histologically diagnosed with lower-grade glioma was analyzed. Tumor segmentations were registered to a standardized space where two anatomical atlases were used to perform a voxel-based comparison of the proximity of segmentations to brain regions of traditional clinical interest. 
RESULTS: Exploring the differences between patients with oligodendrogliomas, isocitrate dehydrogenase (IDH) mutated astrocytomas and patients with IDH wild-type astrocytomas we found that the latter were older, more often had lower Karnofsky performance status and that these tumors were more often found in the proximity of eloquent regions. Eloquent regions are found slightly more frequently in the proximity of IDH-mutated astrocytomas compared to oligodendrogliomas. The regions included in our voxel-based definition of eloquence showed a high degree of association with performing biopsy compared to resection.
CONCLUSION: We present a simple, robust, unbiased and clinically relevant method for assessing tumor location and eloquence in lower-grade gliomas.