Article
The reliability of stereotactic biopsy in suspected low-grade glioma in the era of molecular imaging
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Published: | May 21, 2013 |
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Objective: To date the role of conventional magnetic resonance imaging (MRI)-guided stereotactic biopsy in suspected low grade glioma is discussed controversially, criticism concerns purported inaccuracy, patient morbidity, and unsuitability of the samples for genetic profiling. The objective of the current prospective study was to reevaluate stereotactic biopsy in the light of technical development of recent years including molecular imaging in an unselected patient group.
Method: Ninty-eight consecutive patients with MRI-suspected low grade glioma were included (2006-2010). All patients underwent dynamic O-(2-[18F]fluoroethyl)-1-tyrosine (18FET)-positron emission tomography (PET)-guided stereotactic biopsy to obtain both a histological and molecular diagnosis. Subsequent treatment strategies were determined in the interdisciplinary neurooncological tumor board. Date of last follow-up was September 2012. Progression free survival was estimated with the Kaplan-Meier method. Informed consent was available from all patients.
Results: Median age at diagnosis was 45 years, median KPS was 90. Median follow-up was 33 months. Histopathological analysis revealed 54 grade II gliomas and 44 high-grade gliomas. The transient morbidity rate was 1%. MGMT-promotor methylation, IDH 1/2 mutation and 1p/19q co-deletion were seen in 81%, 65%, and 30% of the tumors. The latter was associated with an oligo-tumor phenotype (p<0.001). In thirteen patients who underwent open tumor resection both tumor grade and biomarker profile could be confirmed. The one-year/two-year progression free survival for verified low- and high-grade glioma was 91%/82% and 66%/38% (p<0.0001) after the application of personalized treatment strategies. Tumor progression was always verified by stereotactic biopsy resulting in the same biomarker profile.
Conclusions: MRI-supected low-grade gliomas represent a highly heterogeneous tumor entity including a high percentage of malignant gliomas. The inclusion of molecular imaging data is essential for target selection to avoid undergrading and undertreatment. Stereotactic biopsy is a safe procedure with low morbidity rate. Biomarker profiles can reliably be determined from small sized tissue samples.