Cerebellar location may predict an unfavourable prognosis in paediatric high-grade glioma.

BACKGROUND: High-grade glioma (HGG) of the cerebellum accounts for only 5% of paediatric HGG. Since little is known about these tumours, the present study aimed at their further characterisation. METHODS: Twenty-nine paediatric patients with centrally reviewed cerebellar HGG were identified from the HIT-GBM/HIT-HGG database. Clinical and epidemiological data were compared with those of 180 paediatric patients with cortical HGG. RESULTS: Patients with cerebellar tumours were younger (median age of 7.6 vs 11.7 years, P=0.028), but both groups did not differ significantly with regard to gender, tumour predisposing syndromes, secondary HGG, primary metastasis, tumour grading, extent of tumour resection, chemotherapy regimen, or radiotherapy. Except for an increased incidence of anaplastic pilocytic astrocytoma (APA) in the cerebellar subset (20.7% vs 3.3%; P<0.001), histological entities were similarly distributed in both groups. As expected, tumour grading had a prognostic relevance on survival. Compared with cortical HGG, overall survival in the cerebellar location was significantly worse (median overall survival: 0.92 ± 0.02 vs 2.03 ± 0.32 years; P=0.0064), and tumour location in the cerebellum had an independent poor prognostic significance as shown by Cox-regression analysis (P=0.019). CONCLUSION: High-grade glioma represents a group of tumours with an obviously site-specific heterogeneity associated with a worse survival in cerebellar location.

[Clinical value of amino acid imaging in paediatric brain tumours. Comparison with MRI]. / Der klinische Wert der Darstellung kindlicher Hirntumore mit Aminosäuren: Vergleich mit MRT.

PURPOSE: To evaluate single photon emission computed tomography (SPECT) using the amino acid l-3-[123I]-alpha-methyl tyrosine (IMT) and contrast enhanced magnetic resonance imaging (MRI) as diagnostic tools in primary paediatric brain tumours in respect of non-invasive tumour grading. Patients, materials, methods: 45 children with primary brain tumours were retrospectively evaluated. IMT uptake was quantified as tumour/nontumour-ratio, a 4-value-scale was used to measure gadolinium enhancement on contrast enhanced MRI. Statistical analyses were performed to evaluate IMT uptake and gadolinium enhancement in low (WHO I/II) and high (WHO III/IV) grade tumours and to disclose a potential relationship of IMT uptake to disruption of blood brain barrier as measured in corresponding MRI scans. RESULTS: IMT uptake above background level was observed in 35 of 45 patients. IMT uptake was slightly higher in high grade tumours but the difference failed to attain statistical significance. Grading of individual tumours was neither possible by IMT SPECT nor by gadolinium enhanced MRI. CONCLUSION: IMT is accumulated in most brain tumours in children. Tumour grading was not possible using IMT or contrast enhancement as determined by MRI. Neither morphological nor functional imaging can replace histology in paediatric brain tumours.

O-(2-[18F]fluorethyl)-L-tyrosine PET in the clinical evaluation of primary brain tumours.

PURPOSE: The aim of this study was to evaluate the differential uptake of O-(2-[18F]fluorethyl)-L-tyrosine (FET) in suspected primary brain tumours. METHODS: Positron emission tomography (PET) was performed in 44 patients referred for the evaluation of a suspected brain tumour. Acquisition consisted of four 10-min frames starting upon i.v. injection of FET. Tumour uptake was calculated as the ratio of maximal tumour intensity to mean activity within a reference region (FETmax). RESULTS: FET uptake above the cortical level was observed in 35/44 lesions. All histologically confirmed gliomas and many other lesions showed FET uptake to a variable extent. No uptake was observed in nine lesions (one inflammatory lesion, one dysembryoplastic neuroepithelial tumour, one mature teratoma, six lesions without histological confirmation). An analysis of uptake dynamics was done in the patients with increased FET uptake (22 gliomas, three lymphomas, three non-neoplastic lesions, three lesions with unknown histology and four other primaries). Upon classification of tumours into low (i.e. WHO I and II) and high grade (i.e. WHO III and IV), a significant difference in FETmax between the two categories was observed only in the first image frame (0-10 min p.i.), with FETmax=2.0 in low-grade and 3.2 in high-grade tumours (p<0.05); no significant differences were found in frame 4 (30-40 min p.i.), with FETmax=2.4 vs 2.7. Similar results were obtained when the analysis was applied only to astrocytic tumours (2.0 vs 3.1 in the first frame; 2.4 vs 2.6 in the fourth frame). CONCLUSION: These initial results indicate that FET PET is a useful method to identify malignant brain lesions. It appears that high- and low-grade brain tumours exhibit a different uptake kinetics of FET. A kinetic analysis of FET PET may provide additional information in the differentiation of suspected brain lesions.

Medulloblastoma: experience of a single institution.

BACKGROUND: The treatment of medulloblastoma has changed considerably during the last decades. Treatment differences between centers may affect a multicenter analysis. We analyzed data from patients of a single institution gathered over a long period of time. PATIENTS: Between 1968 and 1995, 60 patients with medulloblastoma were treated at the University of Munster. Thirty-six were male, 24-female. The ages ranged between 11 months and 32 years. METHODS: Data were retrospectively analyzed from files. Survival was estimated using the Kaplan Meier method and compared using the logranktest and multivariance analysis. RESULTS: The 5-year survival rate was 37%. This included an early mortality of 20% within the first two months, prior to 1980. Significant single, positive, prognostic factors included: no solid metastases (p = 0.001), age > 10 years (p < 0.002); total resection (p < 0.025); posterior fossa radiation with more than 50 Gy (p = 0.04); and intense chemotherapy (p = 0.02). Male patients did slightly worse (not significant). The three-year event-free survival rate of 16 patients treated after 1991 was 70%. CONCLUSION: The prognosis of medulloblastoma has clearly improved with the reduction of the perioperative mortality, standardized radiotherapy, and the introduction of intense chemotherapy.