High-grade gliomas (HGGs; WHO grade III or IV) are the most common and lethal brain malignancy. Patients of Hispanic ethnicity are diagnosed with HGGs earlier than non-Hispanic patients, but they exhibit improved HGG survival following diagnosis. Either environmental or biological factors could explain this survival benefit. We aimed to determine if post-diagnosis advantages would still be present in Hispanic patients with high social vulnerability, an environmental condition predisposing patients to poor oncologic outcomes. HGG outcomes were retrospectively assessed in a cohort of 22 Hispanic patients and 33 non-Hispanic patients treated for HGGs from 2015 to 2020 at a single institution that serves a highly vulnerable region. Compared to non-Hispanic patients, Hispanic patients demonstrated higher social vulnerability index scores (96.8 + 0.7 vs. 76.3 + 4.6; *** p = 0.0002) and a 14-month longer interval between diagnosis and recurrence (19.7 + 5.9 (n = 13) vs. 5.5 + 0.6 months (n = 19); ** p = 0.001). In only those patients with more aggressive IDH-1 wildtype tumors (glioblastoma), Hispanic ethnicity still related to a longer time before recurrence (15.8 + 5.9 months (n = 9); 5.5 + 0.6 months (n = 18); * p = 0.034), and in a multivariate analysis, Hispanic ethnicity predicted time-to-recurrence (* p = 0.027) independent of patient age, functional status, MGMT gene methylation, or treatments received. Therefore, environmental factors, specifically social vulnerability, did not obscure the post-diagnosis benefits associated with Hispanic ethnicity. In future experiments, basic studies should be prioritized which investigate the cellular or genetic mechanisms underlying this ethnicity effect on HGG progression in the hopes of improving care for these devastating malignancies.
Keywords: ethnicity; glioblastoma; high-grade glioma; social vulnerability; time to recurrence.