Elsevier

World Neurosurgery

Volume 73, Issue 2, February 2010, Pages 128-134
World Neurosurgery

Neoplasm
Evaluating the prognostic factors effective on the outcome of patients with glioblastoma multiformis: does maximal resection of the tumor lengthen the median survival?

https://doi.org/10.1016/j.wneu.2009.06.001Get rights and content

Abstract

Background

The ETR that should be undertaken in patients with GBM remains controversial. This study aims to reiterate some independent predicting factors and to underscore the role and the ETR in increasing the survival of patients in the situation of developing countries, that is, without preoperative MRI or tractography. The authors submit additional information to be added to the list of CTRs in the management of malignant brain tumors.

Methods

The authors prospectively analyzed a cohort of 35 consecutive patients with histologically proven GBM who underwent tumor resection in surgically amenable areas for the first time at Sina Hospital, Tehran, between 2003 and 2005. Demographic data, volumetric measurements, and other characteristics identified on preoperative and immediate postoperative MR imaging as well as intraoperative and postoperative clinical data were collectively analyzed by SPSS for Windows, version 11.5 (SPSS, Chicago, Ill).

Results

Cox proportional hazards model multivariate analysis identified the following independent predictors of survival: Karnofsky performance scale ≥80 (P = .01), ETR (P = .01), tumor location in functionally silent prefrontal area (P = .002) vs tumor location in corpus callosum (P = .001), postoperative RT (P = .004), and postoperative chemotherapy (P = .001)

Conclusion

Maximal resection of the tumor volume is an independent variable associated with longer survival times in patient with GBM. Gross total resection should be performed whenever possible, although not at the expense of increased morbidity.

Introduction

Glioblastoma multiforme is the most common primary CNS tumor. Glioblastoma multiforme comprises almost 25% of primary CNS tumors and 50% to 55% of adult gliomas [30]. The optimal treatment for patients with GBM still remains a controversy. Continued refinements in microsurgical techniques and the use of adjunctive technologies have reduced major neurologic morbidity to 8.5% and mortality to 1.7% for patients undergoing craniotomy, respectively [30]. Extensive resection of the primary tumor may lead in a better short-term outcome, but there has been little scientific evidence so far to give maximal tumor resection a credit to prolong survival of the cases. Despite recent advances in surgical techniques and adjunctive therapies, the prognosis for GBM still remains poor with a median survival of approximately 1 year [23]. The results of a critical and comprehensive review of the literature performed by Sanai and Berger [23] proved the lack of class 1 evidence confirming the unbiased effect of ETR on the outcome of patients undergoing surgery for GBM.

Radical resection of malignant gliomas carries the risk of injuring the adjacent vital structures in the brain due to the infiltrative nature of the neoplasm, especially when it is located within the eloquent areas. The major role of surgery is to extirpate the tumor along its macroscopic boundaries and debulk it as completely as possible [12], [22], [33]. Studies have shown that tumor cells may invade far beyond the main tumor mass into the brain due to the infiltrating nature of the malignant gliomas. Although many authors stress the consistent finding of a variable zone of microscopic tumor infiltration of the brain outside of the enhancing area, extending at least as far as the abnormal T2 signal intensity, a great deal of evidence confirms the presence of the tumor cells centimeters beyond the presumed tumor margin [7], [10], [22]. As volumetric data were collected to determine the amount of residual tumor mass as accurately as possible based on pre- and postoperative imaging techniques, maximal resection emerged as a strong predictor of survival [3], [8], [9], whereas high-quality imaging is necessary and should include MRI [1], [27], [29]. Early studies have shown that even hemispherectomy is inadequate for the control of malignant gliomas [12]. In the situation in developing countries wherein several high-technology instruments are used in a restricted way, this requires the operating physician having a grasp of knowledge in the anatomy of the region and paying meticulous attention to changes in color and consistency of the tissue while working in the vicinity of the tumor. With significant reduction in the mass effect of the tumor, the patient may tolerate RT better and experience fewer side effects [9].

Several factors can affect the survival of patients with GBM, the more prominent of which are age, preoperative performance status according to the KPS, tumor location, preoperative imaging characteristics, the extent of tumor excision, and finally, postoperative RT [17]. Performing a prospective multivariate analysis in a cohort of patients operated by a single group of surgeons (FA and AA), we may reliably identify the independent significant predictors of survival of such patients. In this study, we tried to create a multivariate analysis and to overcome the possible selection biases affecting the outcome demonstrated by other authors [28].

Hereby, it is not intended to illustrate a new event but only to present a correctly designed and managed prospective surgical cohort performed by a group of young investigators (FA, MRZ, MA) so that their findings may be added to the literature for possible meta-analysis in the future.

Section snippets

Clinical material and method

Thirty-five consecutive patients with GBM who underwent craniotomy by a single group of surgeons (FA and AA) at Sina Hospital, TUMS, between 2003 and 2005 were enrolled in this study. All cases were classified from the histopathology point of view to GBM or grade 4 astrocytoma, according to the classification of the WHO. The demographic data, clinical manifestations, KPS score on admission, and history of previous head and neck RT were all prospectively recorded.

Volumetric assessments were

Statistical techniques

χ2 test was used to identify the significance of a given variable (P < .05). Cumulative survival duration was measured by the Kaplan-Meier curve. Cox proportional hazards model was used to perform univariate and multivariate analysis and identify independent predictors of survival. Statistical analysis was performed using the Statistical Package for the Social Sciences for Windows—ver.11.5; SPSS, Chicago, Ill).

Clinical findings

The demographic and clinical characteristics of the 35 patients with GBM are summarized in Table 2. There were 24 men (69%) and 11 women (31%) with a mean age of 49.3 years (SD, 17 years). The most common chief complaint on admission was headache and limb paresis (each 34.3%). The most prevalent sign on examination was papilledema (62.9%) followed by hemiparesis (36.7%). Five patients had minor changes in the level of consciousness.

The preoperative KPS score was higher than 80 in 28 cases

Discussion

A long-standing controversy in the neurosurgical literature involves the efficacy of “maximal resection of malignant gliomas” [23]. The optimal extent of resection in any patient depends on the tumor location and size, the patient's general status, and the experience of the individual surgeon [1], [20], [24], [30]. In a comprehensive retrospective analysis on 416 patients with GBM, Lacronix et al [20] illustrated the role of aggressive surgical resection as an independent variable in the

Conclusion

With the advances in surgical techniques and preoperative imaging technologies, it is possible to maximally resect malignant gliomas, even within functionally critical areas without increased morbidity. Gaining enough experience may substitute instruments with sophisticated technology, at least partially, by which the surgeons may deliver acceptable service to their patients in rather difficult situations of the underdeveloped countries. This CTR has not been designed to evaluate the efficacy

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