Comparative Analysis of Subventricular Zone Glioblastoma Contact and Ventricular Entry During Resection in Predicting Dissemination, Hydrocephalus, and Survival

Neurosurgery, Volume 85, Issue 5, November 2019, Pages E924–E932

Ventricular entry during glioblastoma resection and tumor contact with the subventricular zone (SVZ) have both been shown to associate with development of hydrocephalus, leptomeningeal dissemination, distant parenchymal recurrence, and decreased survival. However, prior studies did not analyze these variables together in a single-patient population; therefore, it is unknown which is an independent predictor of these outcomes.

OBJECTIVE: To conduct a comparative outcome analysis of surgical ventricular entry and SVZ contact by glioblastoma in a retrospective cohort of 232 patients.

METHODS: Outcomes studied included hydrocephalus, leptomeningeal dissemination, distant tumor recurrences, and progression-free (PFS) and overall (OS) survival. The Cox proportional regression analyses were adjusted for age at diagnosis, preoperative Karnofsky performance status score, extent of resection, temozolomide and radiation treatments, and tumor molecular status (specifically, IDH1/2 mutation and MGMT promoter methylation).

RESULTS: Surgical ventricular entry, SVZ-contacting glioblastoma, hydrocephalus, leptomeningeal dissemination, and distant recurrences were observed in 85 (36.6%), 114 (49.1%), 19 (8.2%), 78 (33.6%), and 59 (25.4%) patients, respectively. Multivariate, adjusted analysis revealed SVZ tumor contact—but not ventricular entry—associated with hydrocephalus (hazard ratio, HR, 4.20 [1.13-15.7], P = .03), leptomeningeal dissemination (HR 1.93 [1.14-3.28], P = .01), PFS (HR 2.10 [1.53-2.88], P < .001), and OS (HR 1.90 [1.35-2.67], P < .001). Distant recurrences were not associated with either. No interaction between the 2 variables was statistically noted.

CONCLUSION: SVZ contact by glioblastoma was independently associated with the development of hydrocephalus, leptomeningeal dissemination, and decreased survival. SVZ tumor contact was associated with ventricular entry during surgical resections, which did not independently correlate with these outcomes.

Relationship of glioblastoma multiforme to the subventricular zone is associated with survival

Relationship of glioblastoma multiforme to the subventricular zone is associated with survival

Neuro-Oncology 15(1):91–96, 2013

The subventricular zone (SVZ) lines the lateral ventricles and represents the origin of neural and some cancer stem cells. Tumors contacting the SVZ may be more invasive with higher potential to recruit migratory progenitor cells.

Our specific aim was to determine whether SVZ involvement in glioblastoma multiforme (GBM) is associated with a higher recurrence rate and shorter overall survival.

MR imaging and clinical data from 91 patients with GBM treated at our institution were retrospectively reviewed. Tumors were classified as type I if the contrast- enhancing lesion contacted both the SVZ and cortex on pre-operative MRI, type II if only the SVZ was involved, type III if only cortex was involved, and type IV if the lesion did not contact either the SVZ or cortex. Progression-free survival (PFS) and overall survival were estimated based on Kaplan-Meier calculations.

When comparing type I tumors with types II-IV, only 39% of patients with type I tumors were free of recurrence and alive at 6 months, significantly fewer than for all other types combined (67%; P = .01). PFS at 6 months was also less, at only 47% among patients with SVZ-positive tumors, compared with 69% in the SVZ-negative group (P = .002). Patients with SVZ involvement also demonstrated a more rapid time to progression, compared with those not involving the SVZ (P = .003). Patients with GBM involving the SVZ have decreased overall survival and PFS, which may have prognostic and therapeutic implications.