Subventricular zone contacting glioblastoma: tumor size, molecular biological factors and patient survival. (1st December 2020)

• Record Type: Journal Article
• Authors: Hallaert, G.; Pinson, H.; Van den Broecke, C.; Vanhauwaert, D.; Van Roost, D.; Boterberg, T.; Kalala, J. P.
• Is Part Of: Acta oncologica. Volume 59:Number 12(2020)
• Page Start: 1474
• Page End: 1479
• Publication Date: 2020-12-01
• Subjects: Oncology -- Periodicals; Cancer -- Treatment -- Periodicals; 616.992
• DOI: 10.1080/0284186X.2020.1794032
• Languages: English
• ISSNs: 0284-186X

Abstract

Abstract: Background: Several studies show that subventricular zone (SVZ) contact of glioblastoma at diagnosis is a negative prognosticator of survival. In this report, we study glioblastoma patient survival, molecular biological and MRI-based volumetric findings according to SVZ contact. Patients and methods: We conducted a retrospective study of adult patients diagnosed with supratentorial glioblastoma and uniformly treated with temozolomide-based chemoradiotherapy after surgery. The patient cohort was dichotomized according to tumor contact with the SVZ at diagnosis as determined on preoperative MR imaging. Tumor volume was measured using semi-automated segmentation technique. MGMT-gene promoter methylation and IDH mutation status were determined on stored tumor tissue. Kaplan-Meier survival curves were constructed. Cox regression analysis was used to adjust for known confounding factors of glioblastoma patient survival. Results: A total of 214 patients were included in the study of whom 68% belonged to the SVZpos group. Median tumor volume was significantly larger in the SVZpos group (33, 8 mL vs 15, 6 mL; p < .001). MGMT-unmethylated glioblastoma was more frequent in the SVZpos group (61.4% vs 44.9%; p = .028). The overall survival and progression-free survival were 12.2 months and 5.9 months for the SVZpos patient group but 16.9 months and 10.3 months for the SVZneg group (log-rank p = .016 and .007 respectively). In multivariate Cox survival analysis, SVZ contact proved a negative prognostic parameter, independent from age, KPS, extent of resection, MGMT-methylation and IDH mutation status. Conclusions: This study confirms SVZ contact at diagnosis as an independent negative prognostic factor for glioblastoma patient survival. SVZpos glioblastoma had larger tumor size and a larger proportion of unmethylated tumors than SVZneg glioblastoma. Further research is needed to establish whether the observed differences are solely explained by a different molecular profile of SVZpos glioblastoma or by interaction of glioblastoma with the unique SVZ microenvironment.