Treatment patterns and outcomes for cerebellar glioblastoma in the concomitant chemoradiation era: A National Cancer database study.

Cerebellar glioblastoma (GB) is much rarer than its supratentorial counterpart, and potentially of different molecular origin. Prior database studies are of limited size and reported on patients who preceded the validation of temozolomide. Thus, we provide an updated population-based analysis of the treatment trends and outcomes since the standardization of GB adjuvant chemoradiation. Patients diagnosed with primary cerebellar and supratentorial GB were identified from the National Cancer Database spanning 2005-2015. Patients were characterized by demographics, extent of resection, and adjuvant chemotherapy or radiation status. Cohorts were primarily and secondarily assessed for overall survival by tumor site and treatment history, respectively. A total of 655 patients with cerebellar GB were identified (0.6%). Cerebellar GB patients, compared to supratentorial GB were more likely to undergo a biopsy or subtotal resection (13.4% vs 9.3% and 16.0% vs 13.4%, p-value < 0.001), and less likely to pursue adjuvant therapy (48.4% vs 52.7%, p-value < 0.001). Overall median survivals were 9.3 and 9.4 months, respectively. On multivariable analysis, gross total resection, radiation, and chemotherapy were found to be predictors of improved overall survival (HR 0.77, p = 0.038; HR 0.67, p < 0.001; and HR = 0.77, p = 0.030, respectively). While many management principles are currently shared between cerebellar and supratentorial GB, aggressive regimens appear less frequently prescribed. Survival continues to match supratentorial outcomes and may benefit from future, systemic guidance by distinguishing molecular features.