Role of postoperative tumor volume in patients with MGMT-unmethylated glioblastoma

J Neurooncol. 2019 May;142(3):529-536. doi: 10.1007/s11060-019-03124-z. Epub 2019 Feb 21.

Abstract

Purpose: The aim of this study is to investigate the association between postoperative tumor volume and overall survival (OS) of O6-methylguanine DNA methyltransferase (MGMT)-unmethylated glioblastoma patients.

Methods: One hundred-twenty-six patients with MGMT-unmethylated glioblastoma who were treated either with surgical resection or needle biopsy between 2006 and 2015 were included in this retrospective cohort. Pre- and postcontrast T1 weighted images were evaluated in order to determine pre- and postoperative contrast-enhancing tumor volumes (CE-TV). Cox regression models adjusted for other significant prognostic factors were used to investigate the association between postoperative tumor volume and survival.

Results: Complete resection of CE-TV was significantly associated with longer OS in the univariate analysis (HR 0.61; 95% CI 0.40-0.94; p = 0.02). However, this fact could not be confirmed after adjusting the model for other relevant prognostic factors (HR 1.01; 95% CI 0.65-1.55; p = 0.962). Postoperative CE-TV was significantly associated with survival in both univariate (HR: 1.04; 95% CI 1.025-1.055; p < 0.001) and multivariate analyses (HR: 1.027; 95% CI 1.005-1.049; p = 0.014).

Conclusions: Although complete resection of tumor tissue was not significantly associated with longer OS in MGMT-unmethylated GBM patients, maximum safe resection should always be attempted, since postoperative tumor volume is strongly associated with OS.

Keywords: Glioblastoma; Gross-total resection; MGMT-methylation; Surgery.

MeSH terms

  • DNA Methylation*
  • DNA Modification Methylases / genetics*
  • DNA Repair Enzymes / genetics*
  • Female
  • Follow-Up Studies
  • Glioblastoma / genetics
  • Glioblastoma / mortality*
  • Glioblastoma / pathology*
  • Glioblastoma / surgery
  • Humans
  • Male
  • Middle Aged
  • Neurosurgery / methods*
  • Postoperative Complications*
  • Prognosis
  • Retrospective Studies
  • Survival Rate
  • Tumor Suppressor Proteins / genetics*

Substances

  • Tumor Suppressor Proteins
  • DNA Modification Methylases
  • MGMT protein, human
  • DNA Repair Enzymes