A critical evaluation of cystic features in primary glioblastoma as a prognostic factor for survival: Clinical article
Department of Neurological Surgery, University of California, San Francisco, California, USA. Journal of Neurosurgery
(Impact Factor: 3.74).
07/2011; 115(4):754-9. DOI: 10.3171/2011.5.JNS11128
The presence of cystic features in glioblastoma (GBM) has been described as a favorable prognostic factor. The aim of this study was to determine the survival outcome in patients undergoing surgery for newly diagnosed primary GBM with a large cystic component as compared with a large cohort of patients with noncystic GBM, while controlling for well-characterized prognostic factors.
A retrospective review of 354 consecutive patients treated with resection of primary GBM was performed using medical records and imaging information obtained at the University of California, San Francisco from 2005 to 2009. Within this cohort, 37 patients with large cysts (≥ 50% of tumor) were identified. Clinical presentations and surgical outcomes were statistically compared between the cystic and noncystic patients.
There were no statistically significant differences in clinical presentation between groups, including differences in age, sex, presenting symptoms, tumor location, or preoperative functional status, with the exception of tumor size, which was marginally larger in the cystic group. Surgical outcomes, including extent of resection and postoperative functional status, were equivalent. The median actuarial survival for the patients with cystic GBM was 17.0 months (95% CI 12.6-21.3 months), and the median survival for patients with noncystic GBM was 15.9 months (95% CI 14.6-17.2 months). There was no significant between-groups difference in survival (p = 0.99, log-rank test). A Cox multivariate regression model was constructed, which identified only age and extent of resection as independent predictors of survival. The presence of a cyst was not a statistically significant prognostic factor.
This study, comprising the largest series of cases of primary cystic GBM reported in the literature to date, demonstrates that the presence of a large cyst in patients with GBM does not significantly affect overall survival as compared with survival in patients without a cyst. Preoperative discussions with patients with GBM should focus on validated prognostic factors. The presence of cystic features does not confer a survival advantage.
Available from: Ferdinand von Eggeling
- "Cystic features have also been observed in a number of entities, such as meningioma, hemangioblastoma, or metastatic tumors.1 While cystic low-grade gliomas have been associated with increased postoperative survival compared to non-cystic low-grade gliomas, this is a matter of debate for cystic glioblastoma compared to non-cystic glioblastoma.2,3 "
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ABSTRACT: In about 10% of glioblastoma patients, preoperative MRI discloses the presence of tumor cysts. Whereas the impact of cystic appearance on prognosis has been discussed extensively, only little is known about the tumor cyst fluid. In this study, we tested the feasibility of the surface enhanced laser desorption ionization time of flight (SELDI-TOF) technique to detect cyst fluid proteins.
Cyst fluid was collected from 21 glioblastoma patients for SELDI-TOF analysis and compared to control cerebrospinal fluids from 15 patients with spinal stenosis. Resulting protein peaks with significant differences between groups were further described, using the molecular weight in an internet search of protein databases and publications. Two potential cyst fluid proteins, basigin and ferritin light chain, were selected for immunohistological detection in the histologic slides of the patients, metallothionein (MT) served as negative control.
As supposed from the results of the SELDI-TOF analysis, basigin and ferritin were detected immunohistochemically in the cyst wall, whereas MT was more equally distributed between the cyst wall and the surrounding tumor tissue. Median survival time of the patients was 20 months (range 2 to 102 months) and correlated with age, but not with expression of the three proteins.
The SELDI-TOF approach reveals a number of proteins, potentially present in glioblastoma cyst fluid. Identification of these proteins in tumor cells may help understand the pathogenetic pathways and the prognostic value of cystic changes.
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The extent of resection (EOR) is a known prognostic factor in patients with glioblastoma. However, gross-total resection (GTR) is not always achieved. Understanding the factors that prevent GTR is helpful in surgical planning and when counseling patients. The goal of this study was to identify demographic, tumor-related, and technical factors that influence EOR and to define the relationship between the surgeon's impression of EOR and radiographically determined EOR.
The authors performed a retrospective review of the electronic medical records to identify all patients who underwent craniotomy for glioblastoma resection between 2006 and 2009 and who had both preoperative and postoperative MRI studies. Forty-six patients were identified and were included in the study. Image analysis software (FIJI) was used to perform volumetric analysis of tumor size and EOR based on preoperative and postoperative MRI. Using multivariate analysis, the authors assessed factors associated with EOR and residual tumor volume. Perception of resectability was described using bivariate statistics, and survival was described using the log-rank test and Kaplan-Meier curves.
The EOR was less for tumors in eloquent areas (p = 0.014) and those touching ventricles (p = 0.031). Left parietal tumors had significantly greater residual volume (p = 0.042). The average EOR was 91.0% in this series. There was MRI-demonstrable residual tumor in 69.6% of cases (16 of 23) in which GTR was perceived by the surgeon. Expert reviewers agreed that GTR could be safely achieved in 37.0% of patients (17 of 46) in this series. Among patients with safely resectable tumors, radiographically complete resection was achieved in 23.5% of patients (4 of 17). An EOR greater than 90% was associated with a significantly greater 1-year survival (76.5%) than an EOR less than 90% (p = 0.005).
The authors' findings confirm that tumor location affects EOR and suggest that EOR may also be influenced by the surgeon's ability to judge the presence of residual tumor during surgery. The surgeon's ability to judge completeness of resection during surgery is commonly inaccurate. The authors' study confirms the impact of EOR on 1-year survival.
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