Association between Facility Volume and Overall Survival for Patients with Grade II Meningioma after Gross Total Resection.

BACKGROUND: The role of adjuvant radiation after gross total resection (GTR) for grade II meningioma is evolving, prompting further evaluation in NRG-BN003, a phase III national trial. Furthermore, the relationship between facility volume and outcomes in grade II meningioma patients after GTR has not been examined at a national level. We aim to assess overall survival (OS) of GTR grade II meningioma patients by surgical case volume and OS by receipt of adjuvant radiation. METHODS: We used the National Cancer Database to identity 2823 patients diagnosed with grade II meningioma who underwent GTR. Propensity score matching was applied to balance covariates in GTR grade II meningioma patients stratified by adjuvant radiation status. Multivariable logistic regression was used to assess factors associated with radiation receipt. Kaplan-Meier and log-rank tests were used to assess OS by facility volume. RESULTS: As facility volume increased, OS increased, with a five-year OS of 72.8% for facilities with GTR grade II meningioma volumes of 8 or less cases per decade and 87.5% for more than 8 cases per decade (p<.0001). There was no difference in five-year OS between GTR alone and GTR with adjuvant radiation (84.8% versus 86.4%; p=.151). Covariates significantly associated with radiation receipt included facility location, facility volume, distance, and tumor size. CONCLUSIONS: Treatment at higher surgical case volume facilities is associated with improved OS for GTR grade II meningioma. These facilities also have more patients receiving adjuvant radiation. However, we observed no difference in OS between adjuvant radiation and surgery alone.