Prognostic Implications of Extent of Resection in Glioblastoma: Analysis from a Large Database

Abstract Objective To analyze the predictors for and clinical impact of gross total resection (GTR) in patients with glioblastoma (GBM). Methods and Materials The National Cancer Database was queried for patients with GBM diagnosed from 2004-2013 with known survival and extent of resection. Patients were grouped based on extent of resection into biopsy alone, subtotal resection (STR), and GTR. Univariable and multivariable (MVA) analyses were performed to investigate factors associated with the likelihood of GTR and overall survival (OS) following diagnosis. Results 27,865 patients met inclusion criteria. Factors associated with increased odds of GTR on MVA included later year of diagnosis, younger age, higher performance status, non-right sided tumors, multifocal tumors, and O6-methylguanine-methyltransferase (MGMT) gene promoter non-hypermethylated tumors (each p < 0.020). Factors associated with improved OS on MVA included younger patient age, female gender, race, lower comorbidity score, higher performance score, smaller tumor size, unifocality, MGMT hypermethylation, radiotherapy, chemotherapy, and facility volume (each p < 0.005). After adjusting for each of these factors, compared to biopsy alone, GTR was associated with improved OS (HR 0.768, p < 0.001), while STR (grouped together) was not (HR 0.995, p = 0.930). Conclusions While a prospective randomized trial on this topic is unlikely to be completed, this large retrospective analysis provides evidence to support the recommendation of GTR in patients with GBM. This study does not support a survival benefit of STR over biopsy alone (when grouped into these two groups), although there may be a subset of patients with near total resection who would benefit.