Article
Management and prognostic factors of intra-axial brainstem tumours
Management und prognostische Faktoren von intraaxialen Hirnstammtumoren
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Published: | April 11, 2007 |
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Objective: The diagnostic value of magnetic resonance imaging (MRI) in the management of intra-axial brainstem glioma is debated. The aim of the current prospective study was to analyze the validity of a MRI based suspicion of a brainstem glioma as verified by stereotactic biopsy and follow-up evaluation.
Methods: The MRI-based diagnostics/characteristics of the tumours were performed independently by a neuroradiologist. Well marginated tumours which occupy <50% of the axial diameter of the brainstem were classified as focal tumours; otherwise a diffuse glioma was assumed. The lesion was considered multi-focally if it involves more than one segment of the brainstem. Histological evaluation was performed in all patients using multi-modally imaging guided stereotactic serial biopsy technique. Length of survival was estimated with the Kaplan Meier method and prognostic factors were obtained from multivariate regression models.
Results: Thirty-nine patients were included. Histological evaluation revealed no tumor (N=3), pilocytic astrocytoma (N=5), WHO Grade II glioma (N=13), malignant glioma (N=8), metastases (N=5), lymphoma (N=3), and an inflammatory disease (N=2). Perioperative morbidity was 2.5%. All patients harbouring no tumor, an inflammatory disease, or a pilocytic astrocytoma survived. Patients with low-grade glioma and malignant glioma have a 1-year survival rate of 75% and 25%, respectively (p<0.001); 1-year survival was in the range of 30% for those with a lymphoma or a metastasis. In the subgroup of a verified brainstem glioma negative predictors for length of survival were a diffuse tumor delineation (p=0.02), a multifocal extension of the tumor (p<0.003), and a higher tumour grade (p<0.0005).
Conclusions: Intra-axial brainstem tumours represent a heterogeneous tumor group with completely different outcome. Stereotactic biopsy is a safe method to obtain a valid tissue diagnosis and should not be omitted before treatment.