Pediatric brain stem gliomas: a review

Evaluation of 18F-FDG PET and MRI associations in pediatric diffuse intrinsic brain stem glioma: a report from the Pediatric Brain Tumor Consortium

The purpose of this study was to assess (18)F-FDG uptake in children with a newly diagnosed diffuse intrinsic brain stem glioma (BSG) and to investigate associations with progression-free survival (PFS), overall survival (OS), and MRI indices.

METHODS

Two Pediatric Brain Tumor Consortium (PBTC) therapeutic trials in children with newly diagnosed BSG were designed to test radiation therapy combined with molecularly targeted agents (PBTC-007: phase I/II study of gefitinib; PBTC-014: phase I/II study of tipifarnib). Baseline brain (18)F-FDG PET scans were obtained in 40 children in these trials. Images were evaluated by consensus between 2 PET experts for intensity and uniformity of tracer uptake. Associations of (18)F-FDG uptake intensity and uniformity with both PFS and OS, as well as associations with tumor MRI indices at baseline (tumor volume on fluid-attenuated inversion recovery, baseline intratumoral enhancement, diffusion and perfusion values), were evaluated.

RESULTS

In most of the children, BSG (18)F-FDG uptake was less than gray-matter uptake. Survival was poor, irrespective of intensity of (18)F-FDG uptake, with no association between intensity of (18)F-FDG uptake and PFS or OS. However, hyperintense (18)F-FDG uptake in the tumor, compared with gray matter, suggested poorer survival rates. Patients with (18)F-FDG uptake in 50% or more of the tumor had shorter PFS and OS than did patients with (18)F-FDG uptake in less than 50% of the tumor. There was some evidence that tumors with higher (18)F-FDG uptake were more likely to show enhancement, and when the diffusion ratio was lower, the uniformity of (18)F-FDG uptake appeared higher.

CONCLUSION

Children with BSG for which (18)F-FDG uptake involves at least half the tumor appear to have poorer survival than children with uptake in less than 50% of the tumor. A larger independent study is needed to verify this hypothesis. Intense tracer uptake in the tumors, compared with gray matter, suggests decreased survival. Higher (18)F-FDG uptake within the tumor was associated with enhancement on MR images. Increased tumor cellularity as reflected by restricted MRI diffusion may be associated with increased (18)F-FDG uniformity throughout the tumor.

Role of temozolomide in the treatment of newly diagnosed diffuse brainstem glioma in children: experience at a single institution

PURPOSE

The purpose of this study was to assess the efficacy of TMZ on diffuse brainstem glioma, either concomitant with radiotherapy or as an adjuvant treatment after radiotherapy in children.

METHODS AND MATERIALS

Eighteen children (median age at diagnosis was 8.3 years) meet the following criteria: (1) newly diagnosed diffuse brainstem glioma; (2) aged less than 18 years old, which were treated with TMZ at Taipei Veterans General Hospital from January 2004 to December 2008. They were divided into two groups according to treatment modalities: a radiotherapy alone followed by adjuvant TMZ (RT+TMZ) group received conventional radiation after initial diagnosis, and a concomitant chemoradiotherapy followed by adjuvant TMZ (CCRT+TMZ) group received concurrent chemotherapy during radiation with TMZ (75 mg/M(2)/day). After completion of the radiotherapy, TMZ (150 mg/M(2)) was administered once per day for five consecutive days for all enrolled patients in each 28-day cycle. We evaluated the progression-free survival in both groups of patients.

RESULTS

There were 10 patients in RT+TMZ group and eight in CCRT+TMZ group. All patients experienced progression of disease. Twelve patients (75%) died, and all deaths were attributed to the disease progression. The median progression-free survival (PFS) was 7.4 months for the RT+TMZ group and 6.4 months for the CCRT+TMZ group. The 6-month and 1-year PFS in the RT+TMZ group were 70% (SD 14%) and 30% (SD 14%), respectively, and in the CCRT+TMZ group, they were 50% (SD 17%) and 0%, respectively. The log-rank test in PFS between the two groups was not statistically significant.

CONCLUSIONS

In this study, CCRT with TMZ followed by adjuvant TMZ did not result in a better outcome when compared with RT alone followed by adjuvant TMZ. In addition, TMZ either as adjuvant therapy or as CCRT did not improve the prognosis of the patients with newly diagnosed diffuse brainstem glioma.

Apparent diffusion and fractional anisotropy of diffuse intrinsic brain stem gliomas

BACKGROUND AND PURPOSE

DIBSGs have the worst prognosis among pediatric brain tumors with no improvement of outcome for several decades. In this study, we determined whether diffusion imaging could improve patient stratification and our understanding of the impact of therapies.

MATERIALS AND METHODS

Nine baseline and 24 follow-up DTI studies performed in 9 patients on a 1.5T clinical MR imaging scanner were reviewed. ADC and FA were measured for the whole lesion and at 5 anatomic levels: the rostral medulla, caudal pons, midpons, rostral pons, and caudal midbrain. Reference data were obtained from 8 controls with normal brain stem, 6 patients with medulloblastoma, and 7 patients with pilocytic astrocytoma.

RESULTS

ADC was higher in untreated DIBSG than in normal brain stem and medulloblastoma (1.14 ± 0.18 [×10⁻³ mm²/s] versus 0.75 ± 0.06 and 0.56 ± 0.05, both P < .001). FA was lower in DIBSG than in normal brain stem (0.24 ± 0.04 versus 0.43 ± 0.02, P < .001) but was higher than that in pilocytic astrocytoma (0.17 ± 0.05, P < .05). Lower baseline ADC and higher FA correlated with a worse clinical course. Correlations were more significant at the caudal midbrain than in other regions. ADC decreased and FA increased after RT. Changes of FA after RT at the caudal midbrain correlated with event-free survival.

CONCLUSIONS

Baseline ADC and FA of DIBSG revealed hypocellular tumors with extensive edema. Diffusion changes after therapy implied reduced edema but did not support a significant response to therapy. The significance of diffusion properties varied with anatomic locations, the caudal midbrain being particularly important.

Radiation therapy in paediatric gliomas: our institutional experience

BACKGROUND AND PURPOSE

The aim of our retrospective study was to analyze the clinical outcome of paediatric glioma patients treated with radiation therapy (RT) in our institution.

MATERIAL AND METHODS

We retrieved the case records of all children with gliomas (age < 18 years) who received RT in our department between 2004 and 2007. We analyzed the information regarding patients' demography, clinical details, treatment given, RT details, and survival. The event-free survival (EFS), the period from the date of completion of RT to the date of the event, i.e. death/recurrence, was calculated with respect to age, sex, location of tumour (brainstem vs. non-brainstem), histopathology (low grade vs. high grade), extent of surgical resection, dose and duration of RT, and use of chemotherapy.

RESULTS

A total of 70 children with glioma received RT during the above-mentioned period. The 3-year EFS rate for all patients was 44% and the median EFS period was 18 months. The 3-year EFS in patients who underwent surgical decompression and no surgery was 58% and 25%, respectively (p < 0.05). Patients with brainstem lesions had statistically significantly lower 3-year EFS to non-brainstem gliomas (28% vs. 56%, p < 0.01). Chemotherapy use showed no statistically significant trend towards better survival.

CONCLUSIONS

RT is an effective modality of treatment in paediatric glioma patients in our setup. Early use of RT in incompletely resected low-grade gliomas is worth revisit-ing. Results of chemotherapy in high-grade glioma and brainstem gliomas are encouraging.

Balloon-assisted superselective intra-arterial cerebral infusion of bevacizumab for malignant brainstem glioma. A technical note

Malignant brainstem gliomas (BSG) are rare tumors in adults, associated with a grim prognosis and limited treatment options. Currently, radiotherapy represents the mainstay of treatment, although new studies suggest an increased role for certain chemotherapeutic agents. Intravenous (IV) administration of bevacizumab (Avastin, Genentech Pharmaceuticals) has been shown to be active in the treatment of some enhancing malignant brainstem gliomas. The IV route of administration, however, carries a risk of systemic side effects such as bowel perforation, wound disrepair and pulmonary embolism. In addition, the percentage of IV drug that reaches the tumor site is restricted by the blood brain barrier (BBB).Weill Cornell Brain Tumor Center, Department of Neurosurgery, Weill Cornell Medical College of Cornell University: New York, NY, USA. This technical report describes our protocol in performing superselective intra-arterial cerebral infusion (SIACI) of bevacizumab using endovascular balloon-assistance in the top of the basilar artery in a patient with a recurrent malignant brainstem glioma. It represents the first time such a technique has been performed for this disease. This method of drug delivery may have important implications in the treatment of both adult and pediatric brainstem gliomas.

Preclinical evaluation of radiation and perifosine in a genetically and histologically accurate model of brainstem glioma

Brainstem gliomas (BSG) are a rare group of central nervous system tumors that arise mostly in children and usually portend a particularly poor prognosis. We report the development of a genetically engineered mouse model of BSG using the RCAS/tv-a system and its implementation in preclinical trials. Using immunohistochemistry, we found that platelet-derived growth factor (PDGF) receptor alpha is overexpressed in 67% of pediatric BSGs. Based on this observation, we induced low-grade BSGs by overexpressing PDGF-B in the posterior fossa of neonatal nestin tv-a mice. To generate high-grade BSGs, we overexpressed PDGF-B in combination with Ink4a-ARF loss, given that this locus is commonly lost in high-grade pediatric BSGs. We show that the likely cells of origin for these mouse BSGs exist on the floor of the fourth ventricle and cerebral aqueduct. Irradiation of these high-grade BSGs shows that although single doses of 2, 6, and 10 Gy significantly increased the percent of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive nuclei, only 6 and 10 Gy significantly induce cell cycle arrest. Perifosine, an inhibitor of AKT signaling, significantly induced TUNEL-positive nuclei in this high-grade BSG model, but in combination with 10 Gy, it did not significantly increase the percent of TUNEL-positive nuclei relative to 10 Gy alone at 6, 24, and 72 hours. Survival analysis showed that a single dose of 10 Gy significantly prolonged survival by 27% (P = 0.0002) but perifosine did not (P = 0.92). Perifosine + 10 Gy did not result in a significantly increased survival relative to 10 Gy alone (P = 0.23). This PDGF-induced BSG model can serve as a preclinical tool for the testing of novel agents.

Pediatric high-grade gliomas and diffuse intrinsic pontine gliomas

Pediatric high-grade gliomas represent approximately 10% of all pediatric brain tumors. Similar to adult high-grade gliomas, they behave very aggressively, and these children have a very poor prognosis despite a variety of therapies that include chemotherapy and radiotherapy. In this review, we present an overview of both pediatric high-grade gliomas and diffuse intrinsic pontine gliomas with a focus on their epidemiology, etiology, presentation, prognostic factors, biology, treatment modalities, outcomes, and future research directions.

Pediatric low-grade gliomas

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.

Neuroimaging of pediatric brain tumors: from basic to advanced magnetic resonance imaging (MRI)

In this review, the basic magnetic resonance concepts used in the imaging approach of a pediatric brain tumor are described with respect to different factors including understanding the significance of the patient's age. Also discussed are other factors directly related to the magnetic resonance scan itself including evaluating the location of the tumor, determining if the lesion is extra-axial or intra-axial, and evaluating the contrast characteristics of the lesion. Of note, there are key imaging features of pediatric brain tumors, which can give information about the cellularity of the lesion, which can then be confirmed with advanced magnetic resonance imaging (MRI) techniques. The second part of this review will provide an overview of the major advanced MRI techniques used in pediatric imaging, particularly, magnetic resonance diffusion, magnetic resonance spectroscopy, and magnetic resonance perfusion. The last part of the review will provide more specific information about the use of advanced magnetic resonance techniques in the evaluation of pediatric brain tumors.

Pediatric brain tumors: current treatment strategies and future therapeutic approaches

Pediatric CNS tumors are the most common solid tumors of childhood and the second most common cancer after hematological malignancies accounting for approximate 20 to 25% of all primary pediatric tumors. With over 3,000 new cases per year in the United States, childhood CNS tumors are the leading cause of death related to cancer in this population. The prognosis for these patients has improved over the last few decades, but current therapies continue to carry a high risk of significant side effects, especially for the very young. Currently a combination of surgery, radiation, and chemotherapy is often used in children greater than 3 years of age. This article will outline current and future therapeutic strategies for the most common pediatric CNS tumors, including primitive neuroectodermal tumors such as medulloblastoma, as well as astrocytomas and ependymomas.

Brainstem gliomas in children and adults

PURPOSE OF REVIEW

The purpose of this review is to determine if recent advances in diagnostic and treatment modalities result in improvement in the pattern of care of brainstem gliomas.

RECENT FINDINGS

New MRI techniques may contribute to differential diagnosis and aid neurosurgeons in removing resectable brainstem tumors. A better radiological analysis of these heterogeneous tumors improves their classification and helps to better distinguish prognosis subgroups. However, biopsy remains indicated in many contrast enhancing brainstem masses in adults because of the great variety of differential diagnosis.

SUMMARY

Diffuse brainstem glioma is the most common subtype of brainstem tumor and remains a devastating malignancy in children. Conventional radiotherapy is the standard of care and chemotherapy has been disappointing to date. Given the lack of efficacy of conventional drugs, a better understanding of the biology of this tumor is the key to more targeted therapy.

Brainstem gliomas--retrospective analysis of 86 patients

Brainstem gliomas constitute 10% of brain tumors in children and less than 2% in adults. Since therapeutic options are limited and brainstem gliomas are associated with a high morbidity and mortality, we sought to analyze the prognostic factors associated with a better outcome. We reviewed the records of 86 patients with brainstem gliomas treated between 1996 and 2006. We recorded demographic and clinical variables as well as radiological findings and survival. Patients were divided in two groups regarding overall survival: late progressors (survival >or=12 months) or early progressors (survival<12 months). Of 86 patients with brainstem gliomas, 55.8% were females. The mean age at diagnosis was 14.2 years (range 1 to 52 years). Twenty-four (27.9%) patients were adults. Lesions were located at pons in 75.6% of patients, midbrain in 15.1% and medulla in 9.3%. There was no difference between early and late progressors concerning gender, age at onset, location at pons, presence of necrosis or contrast enhancement observed at MRI or surgical resection. In both univariate and multivariate analysis, only a short duration of symptoms before diagnosis (<3 months) was associated with a worst prognosis (odds ratio 5.59, 95% CI 1.94 to 16, p=0.0014). A short duration of symptoms, which may imply a more aggressive tumor, was associated with a worst prognosis in patients with brainstem gliomas. This information may be useful in the selection of patients for future therapeutic trials.

Motexafin gadolinium and involved field radiation therapy for intrinsic pontine glioma of childhood: a Children's Oncology Group phase I study

The purpose of this study was to determine the dose-limiting toxicities, maximum tolerated dose, pharmacokinetics, and intratumor and brain distribution of motexafin gadolinium (MGd) with involved field radiation therapy in children with newly diagnosed intrinsic pontine gliomas. MGd was administered as a 5-min intravenous bolus 2-5 h prior to standard radiation. The starting dose was 1.7 mg/kg. After first establishing that 5 doses/week for 6 weeks was tolerable, the dose of MGd was escalated until dose-limiting toxicity was reached. Radiation therapy was administered to 54 Gy in 30 once-daily fractions. Forty-four children received MGd at doses of 1.7 to 9.2 mg/kg daily prior to radiation therapy for 6 weeks. The maximum tolerated dose was 4.4 mg/kg. The primary dose-limiting toxicities were grade 3 and 4 hypertension and elevations in serum transaminases. Median elimination half-life and clearance values were 6.6 h and 25.4 ml/kg/h, respectively. The estimated median survival was 313 days (95% confidence interval, 248-389 days). The maximum tolerated dose of MGd and the recommended phase II dose was 4.4 mg/kg when administered as a daily intravenous bolus in conjunction with 6 weeks of involved field radiation therapy for pediatric intrinsic pontine gliomas.

Inter-observer variability in the measurement of diffuse intrinsic pontine gliomas

Diffuse intrinsic pontine glioma (DIPG) is an invasive pediatric brainstem tumor with a poor prognosis. Patients commonly enter investigational trials, many of which use radiographic response as an endpoint for assessing drug efficacy. However, DIPGs are difficult to measure on magnetic resonance imaging (MRI). In this study, we characterized the reproducibility of these commonly performed measurements. Each of four readers measured 50 MRI scans from DIPG patients and inter-observer variability was estimated with descriptive statistics. Results confirmed that there is wide variability in DIPG tumor measurements between readers for all image types. Measurements on FLAIR imaging were most consistent. For patients on clinical trials, measurement of DIPG should be performed by a single reader while comparing prior images side-by-side. Endpoints for clinical trials determining efficacy in this population should also include more objective measures, such as survival, and additional endpoints need to be investigated.

Diffuse intrinsic brainstem tumors in neonates. Report of two cases

The authors report on 2 newborn infants with the unusual presentation of intrinsic brainstem tumors. Both nondysmorphic, full-term neonates had cranial nerve palsies and hypotonia. Diagnoses of diffuse intrinsic brainstem gliomas were made on the basis of magnetic resonance imaging, which showed large expansive, nonenhancing intrinsic pontine masses. Intrinsic pontine tumors, characteristically seen in school-age children, are most often high-grade gliomas that are almost invariably fatal. However, the microanatomy and natural history of pontine tumors in neonates are unknown. With parental consent, both newborns were treated expectantly with supportive care but died of progressive disease by 2 weeks of age. In one child, postmortem examination revealed a primary brainstem primitive neuroectodermal tumor. The authors conclude that, as in older children, neonatal intrinsic brainstem tumors may be of a highly malignant nature. The rapid tumor progression in both cases indicates that where a diagnostic procedure may pose significant risks, supportive observation can aid in distinguishing malignant from benign tumor growth.

Phase I trial of tipifarnib in children with newly diagnosed intrinsic diffuse brainstem glioma

The purpose of this study is to estimate the maximum-tolerated dose (MTD) and describe toxicities and preliminary clinical effects of tipifarnib, a farnesyltransferase (FTase) inhibitor, administered concurrently with radiation therapy in children with newly diagnosed intrinsic diffuse brainstem glioma (BSG). Children >or=3 and <or=21 years of age with newly diagnosed nondisseminated intrinsic diffuse BSG were treated with concurrent tipifarnib and radiation, followed by adjuvant tipifarnib. Escalating doses of tipifarnib were administered orally twice daily, continuously, for the entire duration of radiation, followed by a 2-week break. Postradiation tipifarnib, 200 mg/m(2)/dose, was administered twice daily for 21 consecutive days, in 28-day cycles. Seventeen patients, median age 5.9 years (range, 3.6-13.8), received external beam radiation therapy administered concurrently with tipifarnib at dose levels ranging from 100 to 150 mg/m(2)/dose, followed by adjuvant tipifarnib for up to 24 months in the absence of tumor progression or unacceptable toxicity. Dose-limiting toxicities were grade 3 skin rash in one patient at the 125 mg/m(2) dose level and two patients at the 150 mg/m(2) dose level, and grade 3 pneumonia with a normal absolute neutrophil count (ANC) in one patient at the 150 mg/m(2) dose level. One patient had isolated grade 4 neutropenia at the 150 mg/m(2) dose level. The MTD of tipifarnib administered was estimated as 125 mg/m(2)/dose b.i.d. When administered concurrently with radiation, the dose-limiting toxicities of tipifarnib are rash, infection with normal ANC, and neutropenia. The MTD of tipifarnib with concurrent radiation is 125 mg/m(2)/dose b.i.d. One-year survival and progression-free survival estimates are 36.4% (SE 16.7%) and 9.4% (SE 6.3%), respectively.

Pediatric brain stem lesions: introduction of a scoring system for clinical evaluation and their treatment analysis

INTRODUCTION

Brainstem lesions in pediatric age group include mainly gliomas. As these are not usually amenable to complete surgical resection, multimodality treatments are used. To assess treatment responses, Karnofsky's Performance Score (KPS) has been the gold standard; however, in pediatric patients, comprehensive neurological examination is more valuable.

OBJECTIVE

Our purpose was to formulate neurological examination based scoring system and compare its effectiveness with KPS.

MATERIALS AND METHODS

A retrospective analysis of 37 pediatric patients with brainstem lesions was performed. All these patients were assessed both pre- and post-treatment and in every follow up using standard KPS and our proposed scoring system, Kumar's and Samir's Score (K&SS). K&SS was devised choosing the common clinical features and those affecting outcome the most. Twenty-two features were hence selected, and points were allotted to each according to their functional importance, with range from 22 to 100.

RESULTS AND DISCUSSION

Twenty-seven had gliomas, and in nonglioma group, seven had brainstem tuberculosis (BSTB). Nineteen patients with BSG were less than 6 years of age. Most gliomas were pilocytic astrocytomas (n = 21). Outcome analysis of patients in both groups using KPS showed deterioration or no change in the scores in majority whereas using K&SS, most patients showed improvement.

CONCLUSION

Gliomas form majority of pediatric brainstem lesions, with high occurrence of BSTB in nongliomatous group. Our proposed scoring system, based on comprehensive neurological examination, is more sensitive than KPS in treatment analysis of brainstem lesions.

Citrate in pediatric CNS tumors?

BACKGROUND AND PURPOSE

In a subset of in vivo MR spectra acquired from pediatric brain tumors, we have observed an unassigned peak. The goal of this study was to determine the molecule of origin, and the prevalence and concentration of this chemical in various pediatric brain tumors.

MATERIALS AND METHODS

Single-voxel point-resolved spectroscopy (PRESS) spectra from 85 patients with brain tumors and 469 control subjects were analyzed. Citrate seemed to be a likely candidate, and model spectra of citrate were added to the basis set of metabolites for automated processing with use of LCModel software. Absolute "apparent" concentrations of citrate and the Cramer-Rao lower bounds (CRLB), indicators for the reliability of detection, were determined.

RESULTS

"Apparent" citrate was detected in 26 of 85 patients with CRLB of less than 25%. Diffuse intrinsic brain stem glioma (DIBSG) had the highest mean concentration (4.0 +/- 1.1 mmol/kg in all subjects), and 8 of 12 patients had CRLB less than 25%. A significant reduction of citrate (P < .01) was observed in 6 DIBSGs that had follow-up MR spectroscopy studies after radiation therapy. "Apparent" citrate with CRLB less than 25% was detected in 5 of 22 medulloblastomas (mean citrate, 2.9 +/- 2.2 mmol/kg), in 5 of 14 ependymomas (2.6 +/- 1.8 mmol/kg), 5 of 14 astrocytomas (1.9 +/- 1.2 mmol/kg), and 3 of 23 pilocytic astrocytomas (1.4 +/- 1.1 mmol/kg). In control subjects older than 6 months, CRLB less than 25% was not observed, whereas CRLB less than 25% was observed in 39 of 194 subjects younger than 6 months,.

CONCLUSION

MR signal consistent with citrate was observed in pediatric brain tumors and in the developing brain of infants younger than 6 months.

Metabolism of diffuse intrinsic brainstem gliomas in children

Progress in the development of effective therapies for diffuse intrinsic brainstem gliomas (DIBSGs) is compromised by the unavailability of tissue samples and the lack of noninvasive markers that can characterize disease status. The purpose of this study was to compare the metabolic profile of DIBSGs with that of astrocytomas elsewhere in the CNS and to determine whether the measurement of metabolic features can improve the assessment of disease status. Forty in vivo MR spectroscopy (MRS) studies of 16 patients with DIBSG at baseline and after radiation therapy were retrospectively reviewed. Control data for baseline studies of DIBSGs were obtained from 14 untreated regular and anaplastic astrocytomas. All spectra were acquired with single-voxel, short echo-time (35 ms), point-resolved spectroscopy. Absolute metabolite concentrations (mmol/kg) and lipid intensities (arbitrary units) were determined. At baseline, creatine and total choline (tCho) were significantly lower in DIBSGs than in astrocytomas elsewhere in the CNS (4.3 +/- 1.1 vs. 7.5 +/- 1.9 mmol/kg, p < 0.001; 1.9 +/- 0.7 vs. 4.2 +/- 2.6, p < 0.001). Serial MRS in individual subjects revealed increasing levels of tCho (p < 0.05) and lipids (p < 0.05) and reduced ratios of N-acetylaspartate, creatine, and myoinositol relative to tCho (all p < 0.01). Metabolic progression defined by increased tCho concentration in serial MRS preceded clinical deterioration by 2.4 +/- 2.7 months (p < 0.04). Low tCho of DIBSG at baseline is consistent with low proliferative tumors. Subsequent metabolic changes that have been associated with malignant degeneration preceded clinical deterioration. MRS provides early surrogate markers for disease progression.

Treatment of newly diagnosed diffuse brain stem gliomas in children: in search of the holy grail

Diffuse brain stem glioma is the most devastating of pediatric malignancies. Virtually all children with this disease die within 1-2 years of diagnosis. After three decades of exhaustive research, the key to controlling this malignancy still eludes us. Attempts to improve survival using radiation, chemotherapy and biologic agents have yet to culminate in meaningful advances. Recent advances in molecular biology have led to the development of more targeted therapies, which are now being introduced in clinical trials for children with brain stem glioma. As our understanding of the biology of this disease improves, so too will our ability to target it more effectively. Real strides in improving the lives of children with brain stem glioma may finally be within our grasp.

Pontine mass presenting as anxiety, obsessions, and severe eating problems: a case report

Psychiatric symptoms are rarely reported as presenting symptoms in brainstem gliomas in children, with anxiety being the most common one. An 8-year-old girl patient had loss of appetite, weight loss, and difficulty in swallowing severe enough to warrant parenteral nutrition and hospitalization. Psychiatric examination revealed ego-dystonic obsessions related with choking and compulsory religious rituals. Symptoms partially responded to psychotropic treatment. However, because of unremitting hiccups and left-sided weakness, brain imaging was conducted, and magnetic resonance imaging revealed a diffuse pontine mass. The possible explanations for the relationship between the pontine mass and the psychiatric symptoms are discussed.

Treatments for astrocytic tumors in children: current and emerging strategies

Strategies for the treatment of childhood cancer have changed considerably during the last 50 years and have led to dramatic improvements in long-term survival. Despite these accomplishments, CNS tumors remain the leading cause of death in pediatric oncology. Astrocytic tumors form the most common histologic group among childhood brain tumors. They are a heterogeneous group that from a practical therapeutic point of view can be subdivided into low-grade astrocytomas (LGA), optic pathway gliomas (OPG), high-grade astrocytomas (HGA), and brainstem gliomas (BSG). This article focuses on the practical application of treatments that lead to long-term survival, improved quality of life, and reduced long-term complications. Improvement in therapy has led to better outcomes for patients with LGA and OPG. Careful follow-up without any treatment is indicated for a small percentage of patients diagnosed with LGA with an indolent course including children with neurofibromatosis type 1 (NF1). Surgery is the main recommended treatment for children with resectable LGA. Radiation therapy is generally recommended for children with progressive LGA, or after failure of chemotherapy, accomplishing tumor control at 10 years in over 60% of patients. Cytotoxic chemotherapy is usually reserved for children who have had treatment failure with surgery and radiation therapy. It is also offered for children who are too young to be treated with radiation or to defer or avoid radiotherapy. Carboplatin and vincristine achieve 5% complete and 28% partial responses but the use of vincristine is criticized due to poor penetration of the CNS. A regimen of tioguanine, procarbazine, mitolactol, lomustine, and vincristine is frequently administered as an alternative to carboplatin and vincristine in LGA. The introduction of temozolomide has allowed better responses, including a 24% complete response rate compared with 0-5% complete response rates with the previous regimens. OPG are usually histologically LGA, and are treated with similar chemotherapy regimens. OPG is the most common type of brain tumor associated with NF1. Tumor growth in some of these patients is slow with no treatment recommended for an extended period of time. The prognosis for children with the remaining types of astrocytomas remains poor. Surgical resection is typically the first step in the treatment of HGA followed in older children by radiation therapy. The data regarding chemotherapy are mixed. Combination chemotherapy before or after radiation, including cisplatin, carmustine, cyclophosphamide, and vincristine or carboplatin, ifosfamide, cyclophosphamide, and etoposide has provided disappointing results. Clinical trials with temozolomide and agents directed against single targets have not shown substantially better results, but it is hoped that currently conducted studies will provide better outcomes. Diffuse intrinsic BSG are among the most difficult-to-treat brain tumors. Surgical treatment is not recommended for diffuse intrinsic BSG and standard radiation therapy is typically given in children aged >3 years. None of the numerous chemotherapy regimens, including temozolomide, has provided a significant response rate or an improvement in survival. It is expected that newer agents affecting multiple targets such as AEE-788 and antineoplastons, and combinations of single-targeted agents with chemotherapy will provide better results. Careful evaluation of histology, location of the tumor, patient age, and consideration of treatment-related morbidity play an important part in selecting between clinical observation, surgery, radiation, chemotherapy, or investigational agents. The goals of treatment for astrocytic tumors should extend well beyond objective responses and increased survival. Improvement of quality of life is an equally important objective of treatment. Radiation therapy and chemotherapy result in serious late toxicities.

Phase II study of thalidomide and radiation in children with newly diagnosed brain stem gliomas and glioblastoma multiforme

A phase II study was conducted to assess the efficacy of administering daily thalidomide concomitantly with radiation and continuing for up to 1 year following radiation in children with brain stem gliomas (BSG) or glioblastoma multiforme (GBM). Secondary objectives were to obtain preliminary evidence of biologic activity of thalidomide and to evaluate toxicities from chronic administration of thalidomide in this population. Thirteen patients (2-14 years old) with newly diagnosed BSG (12 patients) or GBM (one patient) were enrolled between July 1999 and June 2000. All patients received focal radiotherapy to a total dose of 5,580 cGy. Thalidomide was administered once daily beginning on the first day of radiation and continued for 12 months or until the patient came off study. The starting dose was 12 mg/kg (rounded down to the nearest 50 mg) and was increased by 20% weekly, if tolerated, to 24 mg/kg or 1,000 mg (whichever was lower). Advanced imaging techniques and urine and serum analysis for anti-angiogenic markers were performed in some patients in an attempt to correlate changes with clinical effect of therapy. No patients completed the planned 12 months of thalidomide therapy and all have since died of disease progression. The median duration of therapy was 5 months (range 2-11 months). Nine patients came off study for progressive disease (PD), three patients due to toxicity and one patient withdrew consent. Several patients on this study required more extended courses of high dose steroids than would have been otherwise expected for this population due to significant peritumoral edema and necrosis. No consistent pattern emerged from the biologic correlative studies from 11 patients. However, advanced imaging with techniques such as MR spectroscopy, MR perfusion and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) were helpful in distinguishing growing tumor from treatment effect and necrosis in some patients. The median time to progression (TTP) was 5 months (range 2-11 months) and the median time to death (TTD) was 9 months (range 5-17 months). In this small patient sample adding thalidomide to radiation did not improve TTP or TTD from historical controls, however, toxicity appeared to be increased.

Paediatric brain-stem gliomas: MRI, FDG-PET and histological grading correlation

BACKGROUND

MRI and FDG-PET may predict the histological grading of paediatric brain-stem gliomas.

OBJECTIVE

To assess MRI findings and metabolic imaging using FDG-PET of brain-stem gliomas based on histological grading.

MATERIALS AND METHODS

Included in the study were 20 paediatric patients (age 3-14 years, mean 8.2 years) with brain-stem glioma (five glioblastomas, ten anaplastic astrocytomas and five low-grade astrocytomas). MR images were assessed for the anatomical site of tumour origin, focality, pattern of tumour growth, and enhancement.

RESULTS

All glioblastomas were located in the pons and showed diffuse pontine enlargement with focally exophytic features. Eight anaplastic astrocytomas were located in the pons and demonstrated diffuse pontine enlargement without exophytic features. Low-grade astrocytomas were located in the pons, midbrain or medulla and showed focally exophytic growth features and peripheral enhancement. In 12 patients in whom FDG-PET was undertaken, glioblastomas showed hypermetabolic or hypometabolic lesions, anaplastic astrocytomas showed no metabolic change or hypometabolic lesions and low-grade astrocytomas showed hypometabolism compared with the cerebellum.

CONCLUSION

MRI findings correlated well with histological grading of brain-stem gliomas and MRI may therefore predict the histological grading. FDG-PET may be helpful in differentiating between anaplastic astrocytoma and glioblastomas among high-grade tumours.

Incidence and patterns of neuraxis metastases in children with diffuse pontine glioma

PURPOSE

We performed a retrospective study of patients with diffuse pontine glioma (DPG) who suffered neuraxis metastasis (NM) and characterized the incidence, clinical features, radiologic findings, and patterns of disease dissemination.

METHODS

Magnetic resonance imaging (MRI) of brain and spine was used to assess NM. Some patients also underwent magnetic resonance spectroscopy (MRS) (6 patients) and fluorodeoxyglucose positron emission tomography (FDG-PET) scans (13 patients) to further evaluate areas of metastatic disease. Three patients had histologic confirmation of disease at the site of NM.

RESULTS

Between 1986 and 2003, 18 of 96 patients (17.3%) with DPG developed NM. The median age at diagnosis was 8 years (range, 4-17). All patients had adjuvant chemotherapy and/or focal radiotherapy at diagnosis. The NM occurred at a median of 15 months from diagnosis of DPG (range, 3-96). Three patterns of NM were seen on MRI of brain and spine in these patients; 8 (39%) had parenchymal (PM), 4 (22%) leptomeningeal (PM), 2 (11%) subependymal, and in 5 a combination of two or more patterns. The MRS and FDG-PET scan of suspected areas of metastatic disease was consistent with tumor in 6 of 6 and 12 of 13 patients who underwent these procedures respectively. Three patients also had histologic confirmation of malignant glioma at the site of NM. Despite salvage therapy, all 18 patients have died of disease at a median of 5 months (range, 0.5-20) from diagnosis of neuraxis spread.

CONCLUSION

Our study emphasizes the need for screening patients with DPG for NM at the time of recurrence.

Outcome and prognostic factors in cerebellar glioblastoma multiforme in adults: a retrospective study from the Rare Cancer Network

PURPOSE

The aim of this study was to assess the outcome in patients with cerebellar glioblastoma (GBM) treated in 15 institutions of the Rare Cancer Network.

METHODS AND MATERIALS

Data from a series of 45 adult patients with cerebellar GBM were collected in a retrospective multicenter study. Median age was 50.3 years. Brainstem invasion was observed in 9 (20%) patients. Radiotherapy (RT) was administered to 36 patients (with concomitant chemotherapy, 7 patients). Adjuvant chemotherapy after RT was administered in 8 patients. Median RT dose was 59.4 Gy. Median follow-up was 7.2 months (range, 3.4-39.0).

RESULTS

The 1-year and 2-year actuarial overall survival rate was 37.8% and 14.7%, respectively, and was significantly influenced by salvage treatment (p = 0.048), tumor volume (p = 0.044), extent of neurosurgical resection (p = 0.019), brainstem invasion (p = 0.0013), additional treatment after surgery (p < 0.001), and completion of the initial treatment (p < 0.001) on univariate analysis. All patients experienced local progression: 8 and 22 had progression with and without a distant failure, respectively. The 1- and 2-year actuarial progression free survival was 25% and 10.7%, respectively, and was significantly influenced by brainstem invasion (p = 0.002), additional treatment after surgery (p = 0.0016), and completion of the initial treatment (p < 0.001). On multivariate analysis, survival was negatively influenced by the extent of surgery (p = 0.03) and brainstem invasion (p = 0.02).

CONCLUSIONS

In this multicenter retrospective study, the observed pattern of failure was local in all cases, but approximately 1 patient of 4 presented with an extracerebellar component. Brainstem invasion was observed in a substantial number of patients and was an adverse prognostic factor.

Targeted therapy with antineoplastons A10 and AS2-1 of high-grade, recurrent, and progressive brainstem glioma

BACKGROUND

Brainstem glioma carries the worst prognosis of all malignancies of the brain. Most patients with brainstem glioma fail standard radiation therapy and chemotherapy and do not survive longer than 2 years. Treatment is even more challenging when an inoperable tumor is of high-grade pathology (HBSG). The objective of this report is to summarize the outcome of patients with HBSG treated with antineoplastons in 4 phase 2 trials.

PATIENTS

The following group of 18 patients was evaluable: 4 patients with glioblastomas and 14 patients with anaplastic HBSG. Fourteen patients had diffuse intrinsic tumors. Twelve patients suffered from recurrence, and 6 patients did not have radiation therapy or chemotherapy.

METHODS

Antineoplastons, which consist of antineoplaston A10 (A10I) and AS2-1 injections, were given in escalating doses by intravenous injections. The median duration of antineoplaston administration was 5 months, and the average dosage of A10I was 9.22 g/kg/d and of AS2-1 was 0.31 g/kg/d. Responses were assessed by gadolinium-enhanced magnetic resonance imaging and positron emission tomography.

RESULTS

The overall survival at 2 and 5 years was 39% and 22%, respectively, and maximum survival was more than 17 years for a patient with anaplastic astrocytoma and more than 5 years for a patient with glioblastoma. Progression-free survival at 6 months was 39%. Complete response was achieved in 11%, partial response in 11%, stable disease in 39%, and progressive disease in 39% of patients. Antineoplastons were tolerated very well with 1 case of grade 4 toxicity (reversible anemia).

CONCLUSION

Antineoplastons contributed to more than a 5-year survival in recurrent diffuse intrinsic glioblastomas and anaplastic astrocytomas of the brainstem in a small group of patients.

Paediatric brainstem gliomas: Prognostic factors and management

BACKGROUND

Although most types of tumours involving the brainstem can be surgically removed, patients with diffuse pontine brainstem glioma do not benefit from surgical intervention. The aim of the present study is to establish whether clinical symptoms, their duration prior to diagnosis, the presence of enhancement on MRI scans and the histology of the lesion in paediatric brainstem glioma can guide the surgeon in choosing appropriate management options.

METHODS

We retrospectively reviewed the charts and MRI scans of paediatric patients admitted to Turin's Ospedale Regina Margherita with a diagnosis of brainstem glioma.

RESULTS

Patients with a diffuse pontine tumour on MRI scan (group 1) had a mean duration of symptoms prior to diagnosis of 2.61 months, 77% had symptoms involving at least one cranial nerve at diagnosis, and no MRI scans showed enhancement with gadolinium. No patients underwent radical surgery and 84.6% died. For all other patients (group 2), the mean duration of symptoms at diagnosis was 10.58 months, cranial nerve involvement was present in only 28.5%, and the MRI scans showed enhancement in 78.6%. Radical surgery was the treatment of choice (100%). In this study, survival of patients with diffuse pontine brainstem glioma was 25% at 2 years and survival of patients with any other brainstem glioma was 90% at 2 years.

Advances in the treatment of pediatric brain tumors

Brain tumors are a heterogeneous group of neoplasms with different origins, pathobiologies, treatments and prognoses. The collective contributions from the fields of neuro-oncology, neurosurgery, radiation oncology, neurology, neuropathology, neuroradiology and molecular biology have all led to significant advances in the treatment of certain brain tumors. Ideas from these fields, under the cooperative umbrella of clinical cancer trial consortia, have been tested in large-scale studies. As a result, patient survivals have increased markedly for these tumor types. Unfortunately, there are certain brain tumors in childhood, such as the diffuse intrinsic pontine glioma and atypical teratoid rhabdoid tumor, for which survival advantages have not been found. This review will discuss the current and possible future therapies of the most common pediatric brain tumors and highlight some of the novel imaging modalities that are used pre- and intraoperatively.

Treatment options in childhood pontine gliomas

BACKGROUND

Pontine gliomas are the subgroup of brainstem gliomas with the worst prognosis. Controversial treatment approaches are discussed.

PATIENTS AND METHODS

Data of children with pontine gliomas treated in different prospective multi-center studies who were registered in the HIT-GBM database were pooled and analyzed addressing prognostic factors and the relevance of intensive treatment using contingency tables, Kaplan-Meier curves and Cox regression analyses.

RESULTS

From 1983 to 2001, 153 patients (74 males, 79 females, mean age: 8.1 years) with pontine gliomas were registered. Twenty-one tumors were low-grade and 60 were high-grade gliomas (72 undefined histology: 67 no surgery, 5 incomplete data). Sixteen tumors were partially resected, and 125 were irradiated. Ninety children received chemotherapy according to the "HIT-GBM" protocols ("Hirntumor-Glioblastoma multiforme"). The one-year overall survival rate (1YOS) of all patients with pontine glioma was 39.9+/-4.3%. None of the surviving patients had an observation time longer than 3.9 years. Favorable prognostic factors seemed to be age younger than 4 years, low-grade histology and smaller tumor. All three major treatment modalities including resection, irradiation and chemotherapy had prognostic relevance in univariable analysis. Chemotherapy remained beneficial, even if the analysis was restricted to the subgroup of irradiated tumors (1YOS 45.8+/-5.4% vs. 34.4+/-13.5%, P=0.030).

CONCLUSION

Irradiation is an effective element for the treatment of pontine gliomas. Intensive chemotherapy seems to be important in achieving a better OS.

Advances toward an understanding of brainstem gliomas

The diagnosis of brainstem glioma was long considered a single entity. However, since the advent of magnetic resonance imaging in the late 1980s, neoplasms within this anatomic region are now recognized to include several tumors of varying behavior and natural history. More recent reports of brainstem tumors include diverse sites such as the cervicomedullary junction, pons, midbrain, or the tectum. Today, these tumors are broadly categorized as either diffuse intrinsic gliomas, most often in the pons, or the nondiffuse brainstem tumors originating at the tectum, focally in the midbrain, dorsal and exophytic to the brainstem, or within the cervicomedullary junction. Although we briefly discuss the nondiffuse tumors, we focus specifically on those diffuse brainstem tumors that regrettably still carry a bleak prognosis.

Excision of juvenile pilocytic astrocytoma of the midbrain after radiotherapy

A 13-year-old girl presented with consciousness disturbance, right hemiparesis, and impairment of hearing, swallowing, and ocular movements. A magnetic resonance image demonstrated marked hydrocephalus due to a large cystic tumor (40 x 40 x 30 mm) in the midbrain. Emergency ventricular drainage and stereotactic cyst puncture dramatically improved her condition. Since her family did not agree to surgery on the brain stem, radiotherapy was performed after ventriculoperitoneal shunting. Conventional radiotherapy of 50.4 Gy was temporarily effective, and the growth of the tumor was stabilized until approximately 8 months later when regrowth was noticed. At this stage, with the consent of her family, the tumor was removed via an infratentorial supracerebellar approach. The pathological diagnosis was juvenile pilocytic astrocytoma. The postoperative course was uneventful. No recurrence has been observed during the follow-up period of more than 6 years. This case study shows that initial excision may be appropriate for some low-grade focal lesions in the midbrain when the histological diagnosis and consent have been obtained.

Role of MRI in the management of children with diffuse pontine tumors: a study of 15 patients and review of the literature

BACKGROUND

Pontine tumors carry the worst prognosis of all brain tumors. In most cases, the diagnosis is based solely on MR imaging, without biopsy.

OBJECTIVE

To describe the MR findings of pontine tumors at diagnosis and during follow-up and correlate those with prognosis and to assess the value of MR imaging in patient management compared to clinical evaluation.

MATERIALS AND METHODS

Ninety-one MR scans of 15 children with diffuse pontine tumors were reviewed at diagnosis and during follow-up. The parameters analyzed were as follows: tumor extent, area, and volume; encasement of the basilar artery; presence of exophytic component; necrosis; cysts; hydrocephalus; and intensity and enhancement. Findings were correlated to length of progression-free and overall survival. Trends of amelioration or worsening on imaging were compared with the clinical findings.

RESULTS

Median length of progression-free survival was 10 months, and median survival was 20 months. Only hydrocephalus at presentation was associated with shorter progression-free survival (P=0.02). On the last examination of each patient, the craniocaudal diameter was significantly greater than at diagnosis (P=0.03). The concordance between the imaging and the clinical findings was good.

CONCLUSION

MR is the mainstay for the diagnosis and management of pontine tumors. Cranial growth seems to be an ominous sign. However, the prognostic value of MR is limited. MR findings correlate well with the clinical examination.

Pediatric surgical neuro-oncology: current best care practices and strategies

Significant advances have been made in the diagnosis and treatment of childhood brain tumors. Gross total surgical resection combined with appropriate adjuvant therapies can achieve a high rate of disease control for low grade gliomas, ependymomas and medulloblastomas. High grade gliomas, tumors involving the optic apparatus or diencepahalic structures, diffuse brainstem lesions, and recurrent or metastatic disease still pose considerable therapeutic challenges. We review the current treatment strategies of the three most common types of pediatric brain tumors: gliomas, medulloblastomas and ependymomas, and discuss current and future diagnostic and therapeutic modalities.

Evaluation of quality of life in long-term survivors of paediatric brain stem tumors, treated with radiotherapy

The quality of life in long-term survivors of paediatric brain stem tumors, treated with radiotherapy is evaluated. They suffer predominantly from pre-treatment neurological impairments, which seriously influence their quality of life. The most often observed treatment sequelae are pituitary insufficiency and hearing loss.

Can mouse models for brain tumors inform treatment in pediatric patients?

Brain tumors represent the most common solid tumor of childhood. Although the histology of many pediatric brain tumors is similar to that of their adult counterparts, significant differences exist with regard to tumor location and response to therapy. The biological and genetic basis for this difference is poorly understood, as tumor tissue is generally unavailable for such studies. While targeted therapies directed against specific molecules active in cancer represents a new arsenal of agents for treating these tumors, such agents are generally not being developed for pediatric cancer in particular. Therefore, new agents for treatment of pediatric glioma must be obtained from compounds being tested against tumors of comparable histology in adult patients. Compounding this problem, although brain tumors are among the most lethal tumors of childhood, their absolute number is relatively small. As a consequence, trials with new agents must be prioritized based on the likelihood that a particular agent or combination of agents will have efficacy in pediatric cancer. Mouse models for brain tumors may help to identify targeted agents, and combinations of agents, effective against these tumors. Such data can be used to prioritize therapies for clinical trials in children with these tumors.

A tenascin-C aptamer identified by tumor cell SELEX: systematic evolution of ligands by exponential enrichment

The targeting of molecular repertoires to complex systems rather than biochemically pure entities is an accessible approach that can identify proteins of biological interest. We have probed antigens presented by a monolayer of tumor cells for their ability to interact with a pool of aptamers. A glioblastoma-derived cell line, U251, was used as the target for systematic evolution of ligands by exponential enrichment by using a single-stranded DNA library. We isolated specifically interacting oligonucleotides, and biochemical strategies were used to identify the protein target for one of the aptamers. Here we characterize the interaction of the DNA aptamer, GBI-10, with tenascin-C, an extracellular protein found in the tumor matrix. Tenascin-C is believed to be involved in both embryogenesis and oncogenesis pathways. Systematic evolution of ligands by exponential enrichment appears to be a successful strategy for the a priori identification of targets of biological interest within complex systems.

Phase II study of antineoplaston A10 and AS2-1 in patients with recurrent diffuse intrinsic brain stem glioma: a preliminary report

OBJECTIVE

A phase II study of antineoplaston A10 and AS2-1 was conducted to evaluate the antineoplastic activity in patients with recurrent diffuse intrinsic brain stem glioma.

PATIENTS AND METHODS

This report describes the results of treatment of the first 12 patients admitted to the study. Patients received escalating doses of antineoplaston A10 and AS2-1 by intravenous bolus injections. The median duration of treatment was 6 months and the average dosage of antineoplaston A10 was 11.3 g/kg/day and of antineoplaston AS2-1 0.4 g/kg/day. Responses were assessed by gadolinium-enhanced magnetic resonance imaging of the head.

RESULTS

Of ten evaluable patients, complete response was determined in two cases (20%), partial response in three (30%), stable disease in three (30%) and progressive disease in two (20%). Survival at 2 years was 33.3%. Currently, of all 12 patients, two (17%) were alive and tumour free for over 5 years since initial diagnosis; one was alive for more than 5 years, and another for more than 4 years from the start of treatment. Only mild and moderate toxicities were observed, which included three cases of skin allergy, two cases of anaemia, fever and hypernatraemia, and single cases of agranulocytosis, hypoglycaemia, numbness, tiredness, myalgia and vomiting.

CONCLUSION

The results of this study compared favourably with the responses of patients treated with radiation therapy and chemotherapy. The study continues with accrual of additional patients.

A phase I trial of etanidazole and hyperfractionated radiotherapy in children with diffuse brainstem glioma

PURPOSE

To determine the toxicity and maximum tolerated dose of etanidazole administered concurrently with hyperfractionated radiation therapy (HRT) for children with brainstem glioma.

METHODS AND MATERIALS

Eighteen patients with brainstem glioma were treated with etanidazole and HRT on a dose escalation protocol (Phase I trial) between 1990 and 1996. All patients had MRI confirmation of diffuse pontine glioma and signs/symptoms of cranial nerve deficit, ataxia, or long tract signs of <6 months' duration. Cervicomedullary tumors were excluded. Patients (median age: 8.5 years; 11 males, 7 females) received HRT to the tumor volume plus a 2-cm margin with parallel-opposed 6-15-MV photons. The total dose was 66 Gy in 44 fractions (1.5 Gy b.i.d., with at least 6 h between fractions) for the first 3 patients and 63 Gy in 42 fractions for the subsequent 15 patients. Etanidazole was administered as a rapid i.v. infusion 30 min before the morning fraction of HRT. Planned doses of etanidazole were 1.8 g/m(2) x 17 doses (30.6 g/m(2)) at Step 1 to a maximum of 2.4 g/m(2) x 21 doses (50.4 g/m(2)) at Step 8. Dose escalation was planned with 3 patients at each of the 8 levels.

RESULTS

Three patients were treated at each dose level except Level 2, on which only 1 patient was treated. The highest dose level achieved was Level 7, which delivered a total etanidazole dose of 46.2 g/m(2). Two patients were treated at this level, and both patients experienced Grade 3 toxicity in the form of a diffuse cutaneous rash. Three patients received a lower dose of 42 g/m(2) (dose Level 6) without significant toxicity, and this represents the maximum tolerated dose (MTD). There were 23 cases of Grade 1 toxicity (10 vomiting, 5 peripheral neuropathy, 2 rash, 2 constipation, 1 weight loss, 3 others), 11 cases of Grade 2 toxicity (4 vomiting, 2 skin erythema, 2 constipation, 1 arthralgia, 1 urinary retention, 1 hematologic), and 4 Grade 3 toxicities (2 rash, 1 vomiting, 1 skin desquamation). Grade 2 or 3 peripheral neuropathy was not seen at any dose level. The median survival from the start of treatment was 8.5 months (range: 3-58 months).

CONCLUSION

The MTD of etanidazole in children receiving HRT for brainstem glioma is 42 g/m(2), with cutaneous rash as the dose-limiting toxicity. This is in contrast to the adult experience, which demonstrates a 24% lower MTD of 34 g/m(2) limited by peripheral neuropathy.

Treatment of paediatric pontine glioma with oral trophosphamide and etoposide

To evaluate the overall survival of paediatric patients with pontine gliomas treated with oral trophosphamide and etoposide. Patients between 3 and 17 years of age with either typical diffuse pontine glioma on MRI or histologically proven anaplastic astrocytoma/glioblastoma multiforme located in the pons, were eligible. Treatment consisted of oral trophosphamide 100 mg x m(-2) x day(-1) combined with oral etoposide at 25 mg x m(-2) x day(-1) starting simultaneously with conventional radiation. Twenty patients were enrolled (median age 6 years, male : female=9 : 11). Surgical procedures included: no surgery: five, open biopsy: three, stereotactic biopsy: six, partial resection: three, and sub-total resection: three. Histological diagnoses included pilocytic astrocytoma: one, astrocytoma with no other specification: three, anaplastic astrocytoma: three, glioblastoma multiforme: eight, no histology: five. The most frequent side effects were haematologic and gastrointestinal. There was no toxic death. The response to combined treatment in 12 evaluable patients was: complete response: 0, partial response: three, stable disease: four, and progressive disease: five. All tumours progressed locally and all patients died. The overall median survival was 8 months. The overall survival rates at 1 and 4 years were: 0.4 and 0.05 respectively. This was not different from a control group of patients documented in the same population. Oral trophosphamide in combination with etoposide did not improve survival of pontine glioma patients. The treatment was well tolerated and should be evaluated for more chemoresponsive paediatric malignancies.

Experimental rodent models of brainstem tumors

Despite recent advances in surgical technology, resection is not an option for many brainstem tumors. Experimental models have played essential roles in examining new approaches to therapy. The objective of the present study was to generate models by determining coordinates for safe inoculation into the brainstem of mice and rats, and to establish whether the implantation of heterotopic cells would create reproducible survival curves. Morbidity and survival studies were used to map stereotactic coordinates allowing successful inoculation of tumor cells. Survival studies were used to investigate the time course of tumor growth. Tumor location was examined by light microscopy and magnetic resonance imaging. Mice survived injections of 2 microL of saline at interaural, lateral, and depth coordinates of -2.5, 1.0, and 3.5 mm and -1.5, 1.0, and 3.5 mm. Rats survived injections at interaural, lateral, and depth coordinates of -2.0, 2.0, and 7.0 mm and -3.0, 0, and 7.0 mm. Median survival of mice challenged with 5 x 10(5) EMT6 and 10(4) B16 tumor cells was 11 and 10 days, respectively. Median survival for rats challenged with 10(4) 9L and F98 cells was 14 and 13 days, respectively. The present study demonstrates a feasible approach to preparing models of brainstem tumors. Limitations of these models are discussed.

Carboplatin before and during radiation therapy for the treatment of malignant brain stem tumours: a study by the Société Française d'Oncologie Pédiatrique

Childhood malignant brain stem tumours have a very poor prognosis with a median survival of 9 months despite radiotherapy. No chemotherapy has improved survival. However, carboplatin has been reported to have activity in glial tumours as well as antitumour synergy with radiation. Our aims were to test the response rate of these tumours to carboplatin alone and to evaluate the efficacy on survival of carboplatin alone followed by concurrent carboplatin and radiotherapy. Patients younger than 16 years with typical clinical and radiological presentation of infiltrating brain stem tumour, as well as histologically-documented cases in the atypical forms, were eligible. Two courses of carboplatin (1050 mg/m2 over 3 days) were administered initially. This treatment was followed by a chemoradiotherapy phase including five weekly carboplatin courses (200 mg/m2) and conventional radiotherapy. 38 eligible patients were included. No tumour response was observed after the initial phase. This schedule of first-line carboplatin followed by concurrent carboplatin and radiotherapy did not improve survival.

Magnetic resonance imaging of pediatric brain tumors: state of the art

Over the past 25 years, magnetic resonance imaging (MRI) has developed into the primary imaging tool for evaluation of the central nervous system. MRI is the essential imaging study in the twenty-first century for the evaluation of the child with a brain tumor for initial preoperative diagnosis, treatment planning and image-guided therapies. This article provides an overview of the locations and MRI features of common pediatric tumors of childhood.

Brain stem gliomas

Brainstem gliomas are now regarded as a heterogeneous group of tumors that can be distinguished by age of onset, clinical and radiological presentation and biological behavior. This paper will focus on each subtype of tumor, in children and in adults, and on recent advances in diagnostic criteria and therapeutic options.