Impact of extent of resection and adjuvant therapy in diffuse gliomas of the spine

Abstract

BACKGROUND CONTENTDiffuse gliomas of the spine (DGS)—consisting of intradural intramedullary glioblastoma, astrocytoma, and oligodendroglioma—are exceedingly rare tumors that account for about 2% of primary spinal cord tumors. Much is unknown about their optimal treatment regimen due to a relative lack of clinical outcome data. PURPOSETo provide an updated analysis on treatment and outcomes in DGS. STUDY DESIGN/SETTINGObservational cohort study using The National Cancer Database (NCDB), a multicenter prospectively collected oncology outcomes database. A systematic literature review was also performed to compare the resulting data to previous series. PATIENT SAMPLEPatients with histologically confirmed DGS from 2004 to 2018. OUTCOME MEASURESLong-term overall survival and short-term 30/90-day postsurgical mortality, 30-day readmission, and prolonged hospital length of stay. METHODSImpact of extent of resection and adjuvant therapy on overall survival was evaluated using Kaplan–Meier estimates and multivariable Cox proportional hazards regression. Univariate and multivariate logistic regression was used to analyze covariables and their prognostic impact on short-term surgical outcomes. RESULTSOf the 747 cases that met inclusion criteria, there were 439 astrocytomas, 14 oligodendrogliomas, and 208 glioblastomas. Sixty percent (n=442) of patients received radiation, and 45% (n=324) received chemotherapy. Tumor histology significantly impacted survival; glioblastoma had the poorest survival (median survival time [MS]: 12.3 months), followed by astrocytoma (MS: 70.8 months) and oligodendroglioma (MS: 71.6 months) (p<.001). Gross total resection (GTR) independently conferred a survival benefit in patients with glioblastoma (hazard ratio [HR]: 0.194, p<0.001) and other WHO grade four tumors (HR: 0.223, p=.003). Adjuvant chemotherapy also improved survival in patients with glioblastoma (HR: 0.244, p=.007) and WHO grade four tumors (HR: 0.252, p<.001). Systematic literature review identified 14 prior studies with a combined DGS mortality rate of 1.3%, which is lower than the 4% real-world outcomes calculated from the NCDB. This difference may be explained by selection biases in previously published literature in which only centers with favorable outcomes publish their results. CONCLUSIONSThere remains a paucity of data regarding treatment paradigms and outcomes for DGS. Our analysis, the largest to date, demonstrates that GTR and adjuvant therapy independently improve survival for certain high-grade subgroups of DGS. This best-available data informs optimal management for such patients.