Management of diffuse glioma in children: a retrospective study of 27 cases and review of literature.

Gliomas are the most common CNS tumours in children and present either as circumscribed tumours or diffusely infiltrative neoplasms. Diffuse gliomas develop both in the cerebral hemispheres and the brainstem and have a poor prognosis. Guidelines for the therapy of these tumours are still debated. In this study, we reviewed the clinical features of 27 consecutive patients with diffuse gliomas admitted to the Department of Paediatrics of CHR Citadelle, University of Liège, between 1985 and 2005. We review their clinical presentation, diagnosis, treatment and outcome with reference to the published literature.

Timing of chest radiotherapy in patients with limited stage small cell lung cancer: a systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: We undertook a systematic review and literature-based meta-analysis to determine whether the timing of chest radiotherapy may influence the survival of patients with limited stage small cell lung cancer (LS-SCLC). OBJECTIVES: To establish the most effective way of combining chest radiotherapy with chemotherapy for patients with limited-stage small cell lung cancer in order to improve long-term survival. MATERIALS: Eligible studies were identified according to the Cochrane Collaboration Guidelines and were randomised controlled clinical trials comparing different timing of chest radiotherapy in patients with LS-SCLC. Early chest irradiation was defined as beginning within 30 days after the start of chemotherapy. RESULTS: Seven randomised trials were eligible. The overall survival at 2 years or at 5 years was not significantly different between early or late chest radiotherapy. When only trials were considered that used platinum chemotherapy concurrent with chest radiotherapy, significantly higher 2 and 5-year survival rates were observed when chest radiotherapy (RT) was started within 30 days after the start of chemotherapy (2-year survival: HR: 0.73, 95% CI 0.57-0.94, p=0.01; 5-year survival: HR: 0.65, 95% CI 0.45-0.93, p=0.02). This was even more pronounced when the overall treatment time of chest radiotherapy was less than 30 days. In studies that did not show a survival advantage by early chest radiation, a lower dose-intensity of chemotherapy in the early vs. late arm was observed. CONCLUSIONS: When platinum-based chemotherapy concurrently with chest RT is used, the 2- and 5-year survival rates of patients with LS-SCLC may be in favour of early chest radiotherapy, with a significant difference if the overall treatment time of chest radiation is less than 30 days.

PET/CT of skull base meningiomas using 2-18F-fluoro-L-tyrosine: initial report.

UNLABELLED: Precise delineation of the shape of skull base meningiomas is critical for their treatment and follow-up but is often difficult using conventional imaging such as CT and MRI. We report our results with PET/CT and 2-(18)F-fluoro-L-tyrosine ((18)F-TYR), a marker of amino acid transport, as part of the yearly follow-up of irradiated patients. METHODS: Eleven patients (mean age, 56.5 y) with skull base meningiomas (n=13 lesions) previously irradiated were included. All patients received 300 MBq of (18)F-TYR and were imaged after 30 min of uptake, using a dedicated PET/CT system. The images were first visually examined, and regions of interest (ROI) were then placed over the transaxial PET slice showing the highest uptake. Another ROI was placed over the normal parietal cortex. Tumor-to-cortex activity ratios were obtained by dividing the maximum pixel value in the tumor ROI by the maximum pixel value in the cortex ROI. The PET/CT images were compared with the MR images obtained as part of routine follow-up. RESULTS: Accumulation of the tracer was higher in all meningiomas than in the surrounding tissue. The tumor-to-cortex activity ratio was 2.53 +/- 0.35 (range, 1.3-6). Nonneoplastic tissue such as hyperemic cavernous sinus did not take up the radionuclide and was therefore easily distinguished from the meningioma. The (18)F-TYR anomalies completely overlapped with the MR image in 54% of the tumors, extended beyond the MRI lesion in 38% of the tumors, and were smaller in 8% of the tumors. CONCLUSION: Meningiomas of the skull base are clearly visualized using (18)F-TYR PET/CT, even after irradiation. In addition to MRI, (18)F-TYR PET/CT images may contribute to the evaluation, delineation, and follow-up of these tumors.

Long-term follow-up reveals low toxicity of radiosurgery for vestibular schwannoma.

AIM: The long-term effects of radiosurgery of vestibular schwannomas were investigated in a group of consecutively treated patients. METHODS AND MATERIALS: Between 1995 and 2001, 26 patients (median age: 67, range: 30-82) with a vestibular schwannoma were treated by Linac-based stereotactic radiosurgery (SRS). The median follow-up was 49 months (16-85 months). Only progressive tumours were treated. The median size of tumours was 18 mm (range 9-30 mm). Before SRS, 11 patients had a useful hearing (Gardner-Robertson classes 1 and 2). Single doses of 10-14 Gy were prescribed at the 80% isodose at the tumour margin. The follow-up consisted of regular imaging with MRI the first 3-6 months after the intervention, followed by additional yearly MRIs, a hearing test and a neurological examination. RESULT: The 5-year-probability of tumour control (defined as stabilization or decrease in size) was 95%. Five-year-probability of preservation of hearing and facial nerve function was 96% and 100%, respectively. Hearing was preserved in 10 out of 11 patients who had a normal or useful hearing at the time of treatment. Mild and transient trigeminal toxicity occurred in 2 (8%) patients. It appeared to be significantly correlated to the dose used (p=0.044). However, only a tendency to significance could be demonstrated in the relationship between the two factors when using the Cox analysis (hazard ratio=1.7; 95% CI: 0.7-3.9; p=0.23). CONCLUSIONS: With the doses used, our study demonstrates that SRS provides an equivalent tumour control rate when compared to surgery, as well as on a long-term basis, an excellent preservation of the facial and the acoustic nerves. Although no permanent trigeminal toxicity was observed, our data confirm that doses below 14 Gy can avoid transient dysesthesias.

A pathology-based substrate for target definition in radiosurgery of brain metastases.

PURPOSE: To investigate the need of a margin other than for accuracy reasons in stereotactic radiosurgery (SRS) of brain metastases by means of histopathology. METHODS AND MATERIALS: Evaluation of 45 patients from two pathology departments having had brain metastases and an autopsy of the brain. Growth patterns were reviewed with a focus on infiltration beyond the metastases boundary and made visible with immunohistochemical staining: the metastasis itself with tumor-specific markers, surrounding normal brain tissue with a glial marker, and a possible capsule with a soft tissue marker. Measurements were corrected by a tissue-shrinkage correction factor taken from literature. Outcomes parameters for infiltration were mean and maximum depths of infiltration and number of measured infiltration sites. RESULTS: In 48 of 76 metastases, an infiltration was present. The largest group of metastases was lung cancer. Small-cell lung cancer (SCLC) and melanoma showed a maximum depth of infiltration of > or =1 mm, and other histologies <1 mm. For non-small-cell lung cancer (NSCLC), melanoma, and sarcoma, the highest number of infiltrative sites were observed (median, 2; range, 1-8). SCLC showed significantly larger infiltrative growth, compared with other diagnostic groups. In NSCLC, the highest percentage of infiltration was present (70%). CONCLUSIONS: Infiltrative growth beyond the border of the brain metastasis was demonstrated in 63% of the cases evaluated. Infiltrative growth, therefore, has an impact in defining the clinical target volume for SRS of brain metastases, and a margin of approximately 1 mm should be added to the visible lesion.

Atlas-based automatic segmentation of MR images: validation study on the brainstem in radiotherapy context.

PURPOSE: Brain tumor radiotherapy requires the volume measurements and the localization of several individual brain structures. Any tool that can assist the physician to perform the delineation would then be of great help. Among segmentation methods, those that are atlas-based are appealing because they are able to segment several structures simultaneously, while preserving the anatomy topology. This study aims to evaluate such a method in a clinical context. METHODS AND MATERIALS: The brain atlas is made of two three-dimensional (3D) volumes: the first is an artificial 3D magnetic resonance imaging (MRI); the second consists of the segmented structures in this artificial MRI. The elastic registration of the artificial 3D MRI against a patient 3D MRI dataset yields an elastic transformation that can be applied to the labeled image. The elastic transformation is obtained by minimizing the sum of the square differences of the image intensities and derived from the optical flow principle. This automatic delineation (AD) enables the mapping of the segmented structures onto the patient MRI. Parameters of the AD have been optimized on a set of 20 patients. Results are obtained on a series of 6 patients' MRI. A comprehensive validation of the AD has been conducted on performance of atlas-based segmentation in a clinical context with volume, position, sensitivity, and specificity that are compared by a panel of seven experimented physicians for the brain tumor treatments. RESULTS: Expert interobserver volume variability ranged from 16.70 cm(3) to 41.26 cm(3). For patients, the ratio of minimal to maximal volume ranged from 48% to 70%. Median volume varied from 19.47 cm(3) to 27.66 cm(3) and volume of the brainstem calculated by AD varied from 17.75 cm(3) to 24.54 cm(3). Medians of experts ranged, respectively, for sensitivity and specificity, from 0.75 to 0.98 and from 0.85 to 0.99. Median of AD were, respectively, 0.77 and 0.97. Mean of experts ranged, respectively, from 0.78 to 0.97 and from 0.86 to 0.99. Mean of AD were, respectively, 0.76 and 0.97. CONCLUSIONS: Results demonstrate that the method is repeatable, provides a good trade-off between accuracy and robustness, and leads to reproducible segmentation and labeling. These results can be improved by enriching the atlas with the rough information of tumor or by using different laws of deformation for the different structures. Qualitative results also suggest that this method can be used for automatic segmentation of other organs such as neck, thorax, abdomen, pelvis, and limbs.

Primary central nervous system lymphoma report of 32 cases and review of the literature.

We retrospectively analyzed 32 cases of primary central nervous system lymphoma (PCNSL). Five cases were diagnosed in the period 1987-1994, for 27 cases in the period 1995-2002. There were 17 men and 15 women whose median age was 69 years. Three patients were immunodeficient. The commonest symptoms were focal deficit (16 patients) and cognitive/behaviour disturbances (14 patients). Radiologically, a total of 47 contrast-enhancing lesions were observed in 32 patients; 18 patients had deep-seated lesions. All but two patients underwent histological diagnosis following craniotomy (11 patients) and/or stereotaxic biopsy (22 patients); diagnosis was obtained on CSF cytology in one patient with a third ventricle tumour. In the last patient, the diagnosis was based on the finding of marked tumour shrinkage under corticotherapy, despite two negative histological examinations. Treatment included surgical resection (10 patients), chemotherapy (25 patients) and/or radiotherapy (12 patients). According to the therapeutic recommendations of the GELA (Groupe d'Etude des Lymphomes de l'Adulte), 19 patients received at least two courses of high-dose methotrexate; intrathecal chemotherapy was used in 20 patients with methotrexate and/or cytosine arabinoside. Radiation therapy consisted of whole brain irradiation followed by a boost on tumour site. Nine patients received a combined treatment of chemotherapy and radiotherapy. Twelve patients showed rapid progression to death. At the time of last contact, 28/32 patients (88%) had died, all from PCNSL disease or from complications due to its treatment. The median survival time was 13.9 months. We conclude that PCNSL is an increasingly frequent tumour. The diagnosis is obtained by stereotactic biopsy in the majority of cases. The prognosis appears dismal despite an intensive multidisciplinary therapeutic approach.

Contribution of NMR spectroscopy to the differential diagnosis of a recurrent cranial mass 7 years after irradiation for a pediatric ependymoma.

CASE REPORT: We describe the case of a 5-year-old-boy who underwent surgery and focal radiotherapy for an anaplastic ependymoma of the fourth ventricle. One year later, a spinal metastasis was treated the same way. Six years later, a 16-mm lesion was found on a control MRI in the posterior fossa. To help the differential diagnosis between a relapse, a radio-induced modification, and a new tumor, magnetic resonance spectroscopy was performed. The main findings were a peak at the expected resonance frequency of reduced glutathione, a prominent peak of glutamate/glutamine compounds, a low N-acetylaspartate, and the absence of elevated choline. These findings were suggestive of a meningioma, although the latency between irradiation and development of the lesion was quite short. The diagnosis was confirmed by the pathological examination. CONCLUSION: This case exemplifies the fact that magnetic resonance spectroscopy provides useful biochemical information in such a clinical setting.