Ventricular entry during resection of malignant gliomas: effect on intracranial cerebrospinal fluid tumor dissemination.

The ventricular system is not infrequently entered during the course of maximum cytoreductive surgery for high-grade supratentorial gliomas. It is unclear if ventricular entry during surgery and/or proximity of the tumor to the ventricular system affects cerebrospinal fluid (CSF) tumor dissemination or the patients' overall survival rate. The authors retrospectively reviewed hospital records and neuroradiological studies of 51 patients operated on at the University of Washington between 1987 and 1991. Inclusion in this study necessitated a pathological diagnosis of malignant glioma and the availability of preoperative and postoperative computerized tomography scans or magnetic resonance images. Patients were excluded from the study if they had radiographic evidence of ventricular entry or CSF tumor dissemination prior to referral to the authors' institution. The index operation was defined as the first operation at the University of Washington or (in those patients with ventricular entry) the operation in which the ventricle was entered. Patients were followed until time of death or, in the case of survivors, until February, 1992. The effect of both ventricular entry and the proximity of the tumor to the ventricular system on CSF tumor dissemination and survival rate was assessed using statistical survival methodology. There was no significant difference in time from diagnosis to the index operation between groups compared (Mann-Whitney U-test, p > 0.40). Cerebrospinal fluid dissemination was radiographically documented in 18 patients (35%) following the index operation. This occurrence was not significantly influenced by either ventricular entry during surgery (Mantel-Cox test, p = 0.13), the proximity of the tumor to the ventricular system (p = 0.63), or these two variables combined (p = 0.28). Survival rate following the index operation was not significantly affected by ventricular entry (p = 0.66), proximity of the tumor to the ventricular system (p = 0.61), or these two variable considered in combination (p = 0.44). However, survival rate was significantly decreased once CSF tumor dissemination had occurred (Cox model, p = 0.03).