Brain-stem tumors in childhood: a prospective randomized trial of irradiation with and without adjuvant CCNU, VCR, and prednisone. A report of the Childrens Cancer Study Group

Applying single cell multi-omic analyses to understand treatment resistance in pediatric high grade glioma

Despite improvements in cancer patient outcomes seen in the past decade, tumor resistance to therapy remains a major impediment to achieving durable clinical responses. Intratumoral heterogeneity related to genetic, epigenetic, transcriptomic, proteomic, and metabolic differences between individual cancer cells has emerged as a driver of therapeutic resistance. This cell to cell heterogeneity can be assessed using single cell profiling technologies that enable the identification of tumor cell clones that exhibit similar defining features like specific mutations or patterns of DNA methylation. Single cell profiling of tumors before and after treatment can generate new insights into the cancer cell characteristics that confer therapeutic resistance by identifying intrinsically resistant sub-populations that survive treatment and by describing new cellular features that emerge post-treatment due to tumor cell evolution. Integrative, single cell analytical approaches have already proven advantageous in studies characterizing treatment-resistant clones in cancers where pre- and post-treatment patient samples are readily available, such as leukemia. In contrast, little is known about other cancer subtypes like pediatric high grade glioma, a class of heterogeneous, malignant brain tumors in children that rapidly develop resistance to multiple therapeutic modalities, including chemotherapy, immunotherapy, and radiation. Leveraging single cell multi-omic technologies to analyze naïve and therapy-resistant glioma may lead to the discovery of novel strategies to overcome treatment resistance in brain tumors with dismal clinical outcomes. In this review, we explore the potential for single cell multi-omic analyses to reveal mechanisms of glioma resistance to therapy and discuss opportunities to apply these approaches to improve long-term therapeutic response in pediatric high grade glioma and other brain tumors with limited treatment options.

Radiotherapy for Diffuse Intrinsic Pontine Glioma: Insufficient but Indispensable

Diffuse intrinsic pontine gliomas (DIPGs) account for 10%-20% of all central nervous system tumors in children and are the leading cause of death in children with brain tumors. Although many clinical trials have been conducted over the past decades, the survival outcome has remained unchanged. Over 90% of children die within 2 years of the diagnosis, and radiotherapy remains the standard treatment to date. To improve the prognosis, hyperfractionated and hypofractionated radiotherapy and/or addition of radiosensitizers have been investigated. However, none of the radiotherapy approaches have shown a survival benefit, and the overall survival of patients with DIPG is approximately 11 months. Here, we comprehensively review the management of DIPG with focus on radiotherapy.

Diffuse Intrinsic Pontine Glioma (DIPG): Breakthrough and Clinical Perspective

Diffuse intrinsic pontine glioma (DIPG) mainly affects children with a median age of 6-7 years old. It accounts for 10% of all pediatric tumors. Unfortunately, DIPG has a poor prognosis, and the median survival is generally less than 16-24 months independently from the treatment received. Up to now, children with DIPG are treated with focal radiotherapy alone or in combination with antitumor agents. In the last decade, ONC201 known as dopamine receptor antagonist was uncovered, by a high throughput screening of public libraries of compounds, to be endowed with cytotoxic activity against several cancer cell lines. Efforts were made to identify the real ONC201 target, responsible for its antiproliferative effect. The hypothesized targets were the Tumor necrosis factor-Related Apoptosis-Inducing Ligand stimulation (TRAIL), two oncogenic kinases (ERK/AKT system) that target the same tumor-suppressor gene (FOXO3a), dopamine receptors (DRD2 and DRD3 subtypes) and finally the mitochondrial Caseynolitic Protease P (ClpP). ONC201 structure-activity relationship is extensively discussed in this review, together with other two classes of compounds, namely ADEPs and D9, already known for their antibiotic activity but noteworthy to be discussed and studied as potential "leads" for the development of new drugs to be used in the treatment of DIPG. In this review, a detailed and critical description of ONC201, ADEPs, and D9 pro-apoptotic activity is made, with particular attention to the specific interactions established with its targets that also are intimately described. Pubmed published patents and clinical trial reports of the last ten years were used as the bibliographic source.

Pediatric diffuse intrinsic pontine glioma: where do we stand?

Pediatric diffuse intrinsic pontine glioma (DIPG) represents approximately 20% of all pediatric CNS tumors. However, disease outcomes are dismal with a median survival of less than 1 year and a 2-year overall survival rate of less than 10%. Despite extensive efforts to improve survival outcomes, progress towards clinical improvement has been largely stagnant throughout the last 4 decades. Focal radiotherapy remains the standard of care with no promising single-agent alternatives and no evidence for improvement with the addition of a long list of systemic therapies. A better understanding of the biology of DIPG, though not easy due to obstacles in obtaining pathological material to study, is promising for the development of specific individualized treatment for this fatal disease. Recent studies have found epigenetic mutations to be successful predictors and prognostic factors for developing future management policies. The aim of this review is to give a global overview about the epidemiology, diagnosis, and treatment of DIPG. We further examine the controversial biopsy and autopsy issue that is unique to DIPG and assess the subsequent impact this issue has on the research efforts and clinical management of DIPG.

Tenascin-C expression contributes to pediatric brainstem glioma tumor phenotype and represents a novel biomarker of disease

Diffuse intrinsic pontine glioma (DIPG), an infiltrative, high grade glioma (HGG) affecting young children, has the highest mortality rate of all pediatric cancers. Despite treatment, average survival is less than twelve months, and five-year survival under 5%. We previously detected increased expression of Tenascin-C (TNC) protein in DIPG cerebrospinal fluid and tumor tissue relative to normal specimens. TNC is an extracellular matrix (ECM) glycoprotein that mediates cell-matrix interactions, guides migrating neurons during normal brain development and is thought to maintain the periventricular stem cell niche in the developing brain. Tumor TNC expression is reported in adult glioma and other cancers. However, the pattern and effects of TNC expression in DIPG has not been previously explored. Here, we characterize TNC expression in patient derived pediatric supratentorial HGG (n = 3) and DIPG (n = 6) cell lines, as well as pediatric glioma tumor (n = 50) and normal brain tissue specimens (n = 3). We found tumor specific TNC gene and protein overexpression that directly correlated with higher tumor grade (WHO III and IV, p = 0.05), H3K27 M mutation (p = 0.012), shorter progression free survival (p = 0.034), and poorer overall survival (0.041) in association with these factors. TNC knockdown via lentiviral shRNA transfection of HGG (n = 1) and DIPG (n = 3) cell lines resulted in decreased cell proliferation, migration, and invasion in vitro (p < 0.01), while TNC cDNA transfection resulted in increased cell migration, invasion and proliferation (p < 0.01) as well as altered cell morphology in H3K27 M mutant DIPG lines. Whole transcriptome sequencing analysis (RNA-Seq) on DIPG (n = 3) and HGG (n = 2) cell lines after TNC cDNA, shRNA, and empty vector control transfection revealed the effects of TNC expression level on global gene expression profiles. Together, our findings reveal TNC expression in DIPG in association with H3K27 M mutation and VEGF signaling, and suggest that TNC may contribute to DIPG tumor phenotype, and serve as a clinically detectable biomarker for DIPG.

Pre-irradiation intensive induction and marrow-ablative consolidation chemotherapy in young children with newly diagnosed high-grade brainstem gliomas: report of the "head-start" I and II clinical trials

BACKGROUND

The dismal outcome in children with high-grade brainstem gliomas (BSG) accentuates the need for effective therapeutic strategies. We investigated the role of intensive, including marrow-ablative, chemotherapy regimens in the treatment of young children with newly-diagnosed high-grade BSG.

METHODS

Between 1991-and-2002, 15 eligible children less than 10 years of age with a diagnosis of high-grade BSG were treated on "Head-Start" I and II protocols (HSI and HSII). Treatment included Induction with 4-5 cycles of one of three intensive chemotherapy regimens followed by Consolidation with one cycle of marrow-ablative chemotherapy (thiotepa, carboplatin and etoposide) with autologous hematopoietic cell rescue (AHCR). Irradiation was required for children over 6 years of age or for those with residual tumor at the end of Consolidation.

RESULTS

We had two long-term survivors who were found retrospectively to harbor low-grade glial tumors and thus were not included in the survival analysis. Of the remaining 13 patients, the 1-year event-free (EFS) and overall (OS) survival for these children were 31% (95% CI 9-55%) and 38% (95% CI 14-63%), respectively. Median EFS and OS were 6.6 (95% CI 2.7, 12.7) and 8.7 months (95% CI 6.9, 20.9), respectively. Eight patients developed progressive disease during study treatment (seven during Induction and one at the end of Consolidation). Ten children received focal irradiation, five for residual tumor (three following Induction and two following Consolidation) and five due to disease progression.

CONCLUSIONS

Children with high-grade BSG did not benefit from this intensive chemotherapy strategy administered prior to irradiation.

Pediatric high-grade glioma: biologically and clinically in need of new thinking

High-grade gliomas in children are different from those that arise in adults. Recent collaborative molecular analyses of these rare cancers have revealed previously unappreciated connections among chromatin regulation, developmental signaling, and tumorigenesis. As we begin to unravel the unique developmental origins and distinct biological drivers of this heterogeneous group of tumors, clinical trials need to keep pace. It is important to avoid therapeutic strategies developed purely using data obtained from studies on adult glioblastoma. This approach has resulted in repetitive trials and ineffective treatments being applied to these children, with limited improvement in clinical outcome. The authors of this perspective, comprising biology and clinical expertise in the disease, recently convened to discuss the most effective ways to translate the emerging molecular insights into patient benefit. This article reviews our current understanding of pediatric high-grade glioma and suggests approaches for innovative clinical management.

Surgical and molecular considerations in the treatment of pediatric thalamopeduncular tumors

OBJECTIVE Thalamopeduncular tumors are a group of pediatric low-grade gliomas that arise at the interface of the thalamus and brainstem peduncle. They typically occur within the first 2 decades of life, presenting with progressive spastic hemiparesis. Treatment strategies, including surgical intervention, have varied significantly. The authors present their experience in the treatment of 13 children, ages 2-15 years, with non-neurofibromatosis-related pilocytic astrocytomas located in the thalamopeduncular region. METHODS Between 2003 and 2016, 13 children presenting with progressive spastic hemiparesis due to a pilocytic astrocytoma at the interface of the thalamus and cerebral peduncles were identified. Medical records were reviewed retrospectively for clinical, radiological, pathological, and surgical data. Formalin-fixed, paraffin-embedded tissue was obtained for 12 cases and tested for KIAA1549-BRAF fusion and BRAF V600E point mutation. RESULTS On preoperative diffusion tensor imaging tractography (performed in 12 patients), the ipsilateral corticospinal tract was displaced laterally in 1 case (8.3%), medially in 1 case (8.3%), anterolaterally in 10 cases (83%), and posteriorly in no cases. Ten patients underwent resection via a transtemporal, transchoroidal approach, which was chosen to avoid further damage to motor function in cases of tumors that caused anterolateral or medial corticospinal tract displacement. With this approach, complications included hemianopia, oculomotor palsy, and tremor at a rate of 50%. Among the 12 patients with obtainable follow-up (mean 50.9 months), none received adjuvant therapy, and only 2 (17%) experienced recurrence or progression. KIAA1549-BRAF fusions were present in 10 cases (83%), while BRAF V600E was absent (0%). The 2 fusion-negative tumors had clinical features atypical for the series, including multi-focality and infiltration. CONCLUSIONS Transcortical, transchoroidal resection of thalamopeduncular tumors through the middle temporal gyrus allows for a high rate of gross-total resection and cure. Diffuse tensor tractography is a critical component of the preoperative planning process to determine the location of white matter tracts in proximity. Molecular status may correlate with clinical features, and the presence of BRAF lesions offers an additional target for future novel therapeutics.

Survival with concurrent temozolomide and radiotherapy in pediatric brainstem glioma with relation to the tumor volume

Background:

Brainstem gliomas account for approximately 25% of all posterior fossa tumors. In pediatric age group, it constitutes about 10% of all brain tumors. Brainstem glioma is an aggressive and lethal type of malignancy with poor outcome despite all treatments.

Aim:

We studied the incidence and treatment outcome in pediatric patients with brainstem glioma depending on their tumor volume presenting in our institution in last 5 years. Brain tumors comprised 2.95% of all cancers and brainstem gliomas were 8% of all brain tumors.

Materials and Methods:

Nine pediatric patients were included in this analysis, who were treated with localized external radiotherapy 54–59.4 Gy along with temozolomide 75 mg/m² during the whole course of radiotherapy.

Results:

The median survival in all these patients was 20 months and the overall 2 years survival is 44.4% (4/9). The median survival of patients with primary disease volume <40cc is 26 months whereas when the volume is more than 40cc the median survival is 13.5 months as calculated by Chi-square test.

Conclusion:

As this study includes a small number of patients with unknown histology and treated on the basis of magnetic resonance imaging findings, no definite opinion can be given as some patients may have a low-grade tumor. More studies are required to establish the relation of size of the tumor with survival.

Local delivery methods of therapeutic agents in the treatment of diffuse intrinsic brainstem gliomas

Brainstem gliomas comprise 10-20% of all pediatric central nervous system (CNS) tumors and diffuse intrinsic pontine gliomas (DIPGs) account for the majority of these lesions. DIPG is a rapidly progressive disease with almost universally fatal outcomes and a median survival less than 12 months. Current standard-of-care treatment for DIPG includes radiation therapy, but its long-term survival effects are still under debate. Clinical trials investigating the efficacy of systemic administration of various therapeutic agents have been associated with disappointing outcomes. Recent efforts have focused on improvements in chemotherapeutic agents employed and in methods of localized and targeted drug delivery. This review provides an update on current preclinical and clinical studies investigating treatment options for brainstem gliomas.

DIPG in Children - What Can We Learn from the Past?

Brainstem tumors represent 10–15% of pediatric central nervous system tumors and diffuse intrinsic pontine glioma (DIPG) is the most common brainstem tumor of childhood. DIPG is almost uniformly fatal and is the leading cause of brain tumor-related death in children. To date, radiation therapy (RT) is the only form of treatment that offers a transient benefit in DIPG. Chemotherapeutic strategies including multi-agent neoadjuvant chemotherapy, concurrent chemotherapy with RT, and adjuvant chemotherapy have not provided any survival advantage. To overcome the restrictive ability of the intact blood–brain barrier (BBB) in DIPG, several alternative drug delivery strategies have been proposed but have met with minimal success. Targeted therapies either alone or in combination with RT have also not improved survival. Five decades of unsuccessful therapies coupled with recent advances in the genetics and biology of DIPG have taught us several important lessons (1). DIPG is a heterogeneous group of tumors that are biologically distinct from other pediatric and adult high grade gliomas (HGG). Adapting chemotherapy and targeted therapies that are used in pediatric or adult HGG for the treatment of DIPG should be abandoned (2). Biopsy of DIPG is relatively safe and informative and should be considered in the context of multicenter clinical trials (3). DIPG probably represents a whole brain disease so regular neuraxis imaging is important at diagnosis and during therapy (4). BBB permeability is of major concern in DIPG and overcoming this barrier may ensure that drugs reach the tumor (5). Recent development of DIPG tumor models should help us accurately identify and validate therapeutic targets and small molecule inhibitors in the treatment of this deadly tumor.

Diffuse intrinsic pontine gliomas: treatments and controversies

Diffuse intrinsic pontine gliomas (DIPGs) are a fairly common pediatric brain tumor, and children with these tumors have a dismal prognosis. They generally are diagnosed within the first decade of life, and due to their location within the pons, these tumors are not surgically resectable. The median survival for children with DIPGs is less than 1 year, in spite of decades of clinical trial development of unique approaches to radiation therapy and chemotherapy. Novel therapies are under investigation for these deadly tumors. As clinicians and researchers make a concerted effort to obtain tumor tissue, the molecular signals of these tumors are being investigated in an attempt to uncover targetable therapies for DIPGs. In addition, direct application of chemotherapies into the tumor (convection-enhanced delivery) is being investigated as a novel delivery system for treatment of DIPGs. Overall, DIPGs require creative thinking and a disciplined approach for development of a therapy that can improve the prognosis for these unfortunate children.

Diffuse intrinsic pontine glioma in children and adolescents: a single-center experience

BACKGROUND

Patients with diffuse intrinsic pontine glioma (DIPG) have a very poor prognosis. Only radiotherapy (XRT) has proven to be effective in delaying the disease progression. Several chemotherapy schedules have been applied so far, but none demonstrated significant improvements in progression and survival.

METHODS

We retrospectively analyzed the clinical data of children diagnosed with DIPG at our center (Pediatric Hospital "Regina Margherita," Turin, Italy) between 1999 and 2013. Progression-free survival (PFS) and overall survival (OS) were used to describe the outcomes.

RESULTS

Twenty-four children were included in our report. Patients diagnosed before March 2003 (n = 12) were treated with XRT and vincristine (VCR); the remaining 12 patients received XRT and temozolomide (TMZ). Progression-free survival was 18.8 % at 1 year (SE = 7.6 %), while overall survival was 44.1 % at 1 year (SE = 9.9 %). Median PFS was 8.1 months, whereas median OS was 11.2 months. No statistically significant difference in PFS or OS was evidenced between the two treatment groups.

CONCLUSION

Radiotherapy followed by VCR or TMZ allows obtaining results that are in line with previous reports, with no advantages over other similar treatment schedules. DIPGs are challenging tumors with a dismal outcome. Further research and newer therapies are urgently needed in order to achieve improvements in survival.

Phase 2 study of safety and efficacy of nimotuzumab in pediatric patients with progressive diffuse intrinsic pontine glioma

BACKGROUND

The prognosis of diffuse intrinsic pontine glioma (DIPG) remains poor, with no drug proven to be effective.

METHODS

Patients with clinically and radiologically confirmed, centrally reviewed DIPG, who had failed standard first-line therapy were eligible for this multicenter phase II trial. The anti-epidermal growth factor receptor (EGFR) antibody, nimotuzumab (150 mg/m(2)), was administered intravenously once weekly from weeks 1 to 7 and once every 2 weeks from weeks 8 to 18. Response evaluation was based on clinical and MRI assessments. Patients with partial response (PR) or stable disease (SD) were allowed to continue nimotuzumab.

RESULTS

Forty-four patients received at least one dose of nimotuzumab (male/female, 20/24; median age, 6.0 years; range, 3.0-17.0 years). All had received prior radiotherapy. Treatment was well tolerated. Eighteen children experienced serious adverse events (SAEs). The majority of SAEs were associated with disease progression. Nineteen patients completed 8 weeks (W8) of treatment: There were 2 PRs, 6 SDs, and 11 progressions. Five patients completed 18 weeks (W18) of treatment: 1 of 2 patients with PR at W8 remained in PR at W18, and 3 of 6 children with SD at W8 maintained SD at W18. Time to progression following initiation of nimotuzumab for the 4 patients with SD or better at W18 was 119, 157, 182 and 335 days, respectively. Median survival time was 3.2 months. Two patients lived 663 and 481 days from the start of nimotuzumab.

CONCLUSIONS

Modest activity of nimotuzumab in DIPG, which has been shown previously, was confirmed: A small subset of DIPG patients appeared to benefit from anti-EGFR antibody treatment.

Retrospective evaluation of the outcomes of children with diffuse intrinsic pontine glioma treated with radiochemotherapy and valproic acid in a single center

Diffuse intrinsic pontine glioma is a pediatric oncologic disease with dismal prognosis and no effective treatment. Since 2007, our patients have been using valproic acid as prophylactic anticonvulsant. We have undertaken a retrospective study in order to evaluate the influence of valproate in the outcomes of children with this disease in our center. Patients were treated with weekly carboplatin and vincristine and received conformal radiotherapy, either concurrent or sequential. Event-free survival and overall survival of patients not treated with valproic acid were 6.5 and 7.8 months. Accelerated failure time model (a parametric multivariate regression test for time-to-failure data) showed a statistically significant superiority of the median event-free survival of treated patients (6.5 vs. 9.5 months in treated patients; HR 0.54-95 % CI 0.33-0.87; p < 0.05) and also of overall survival (7.8 vs. 13.4 months in treated patients; HR 0.60-95 % CI 0.37-0.98; p = 0.05).

Management of diffuse pontine gliomas in children: recent developments

The prognosis for children with diffuse intrinsic pontine gliomas (DIPGs) is dismal. Although DIPGs constitute only 10-15 % of all pediatric brain tumors, they are the main cause of death in this group with a median survival of less than 12 months. Standard therapy involves radiotherapy, which produces transient neurologic improvement. Despite several clinical trials having been conducted, including trials on targeted agents to assess their efficacy, there is no clear improvement in prognosis. However, knowledge of DIPG biology is increasing, mainly as a result of research using biopsy and autopsy samples. In this review, we discuss recent studies in which systemic therapy was administered prior to, concomitantly with, or after radiotherapy. The discussion also includes novel therapeutic options in DIPG. Continuing multimodal and multitargeted therapies might lead to an improvement in the dismal prognosis of the disease.

Brainstem glioma: a review

Brainstem gliomas (BGs) are a heterogenous group of gliomas that occur predominately in children. They can be separated into groups on the basis of anatomy and clinical behavior: diffuse intrinsic pontine glioma (DIPG), exophytic medullary glioma, and tectal glioma. DIPG is the commonest BG. Median age at onset is 6.5 years and median survival is less than 1 year. Adults with DIPG survive longer, suggesting a less aggressive and biologically different tumor from that in children. Patients present with cranial nerve dysfunction, long tract signs, or ataxia, either in isolation or in combination. Magnetic resonance imaging shows an infiltrative lesion occupying most of the pons and contrast enhancement is usually not prominent. Standard treatment is fractionated radiotherapy. Platelet-derived growth factor receptor alpha and epidermal growth factor receptor mutations have been identified. Inhibitors of these growth factor receptors are being evaluated in clinical trials. Exophytic medullary and tectal gliomas are relatively indolent tumors that can often be followed closely without treatment.

Diffuse pontine lesions in children with neurofibromatosis type 1: making a case for unidentified bright objects

Using an illustrative case of a presumed pontine unidentified bright object (UBO) with spontaneous lesion regression over 2 years, we review the importance of including UBOs in the differential diagnosis of children with confirmed or possible neurofibromatosis type 1 (NF1) who present with diffuse pontine enlargement and T2-weighted changes on MRI. Asymptomatic children with presumed NF1 and diffuse pontine lesions should not be treated with radiation and should not be biopsied. Prior reports of good prognosis associated with pontine glioma in patients with NF1 may have been unrecognized UBOs in some cases.

Diffuse intrinsic pontine glioma: poised for progress

Diffuse intrinsic pontine gliomas (DIPGs) are amongst the most challenging tumors to treat. Surgery is not an option, the effects of radiation therapy are temporary, and no chemotherapeutic agent has demonstrated significant efficacy. Numerous clinical trials of new agents and novel therapeutic approaches have been performed over the course of several decades in efforts to improve the outcome of children with DIPG, yet without success. The diagnosis of DIPG is based on radiographic findings in the setting of a typical clinical presentation, and tissue is not routinely obtained as the standard of care. The paradigm for treating children with these tumors has been based on that for supratentorial high-grade gliomas in adults as the biology of these lesions were presumed to be similar. However, recent pivotal studies demonstrate that DIPGs appear to be their own entity. Simply identifying this fact releases a number of constraints and opens opportunities for biologic investigation of these lesions, setting the stage to move forward in identifying DIPG-specific treatments. This review will summarize the current state of knowledge of DIPG, discuss obstacles to therapy, and summarize results of recent biologic studies.

A phase 2 study of pegylated interferon α-2b (PEG-Intron(®)) in children with diffuse intrinsic pontine glioma

BACKGROUND

Interferon-α is a cytokine that has demonstrated activity in patients with supratentorial gliomas, but its ideal dose and schedule of administration is unknown. Studies suggest that low-dose, continuous exposure is more efficacious than intermittent, high doses. The authors performed a phase 2 study of recombinant interferon α-2b with monomethoxy polyethylene glycol (PEG-Intron(®)) in children with diffuse intrinsic pontine glioma (DIPG), a population with dismal survival despite decades of clinical investigation. The primary objective was to compare 2-year survival with a historic cohort that received radiation therapy alone.

METHODS

Patients received weekly subcutaneous PEG-Intron(®) at a dose of 0.3 μg/kg beginning 2 to 10 weeks after the completion of radiation therapy until they developed disease progression. Patients were evaluated clinically and radiographically at regular intervals. Serum and urine were assayed for biomarkers before each cycle. Quality-of-life (QOL) evaluations were administered at baseline and before every other cycle of therapy to the parents of patients ages 6 to 18 years.

RESULTS

Thirty-two patients (median age, 5.3 years; range, 1.8-14.8 years) were enrolled and received a median of 7 cycles of therapy (range, from 1 cycle to ≥70 cycles). PEG-Intron(®) was well tolerated, and no decrease in QOL scores was noted in the subset of patients tested. The 2-year survival rate was 14%, which was not significantly improved compared with the historic cohort. However, the median time to progression was 7.8 months, which compared favorably with recent trials reporting a time to progression of 5 months in a similar population.

CONCLUSIONS

Although low-dose PEG-Intron(®) therapy did not significantly improve 2-year survival in children with DIPG compared with an historic control population, it did delay the time to progression.

Paediatric and adult malignant glioma: close relatives or distant cousins?

Gliomas in children differ from their adult counterparts by their distribution of histological grade, site of presentation and rate of malignant transformation. Although rare in the paediatric population, patients with high-grade gliomas have, for the most part, a comparably dismal clinical outcome to older patients with morphologically similar lesions. Molecular profiling data have begun to reveal the major genetic alterations underpinning these malignant tumours in children. Indeed, the accumulation of large datasets on adult high-grade glioma has revealed key biological differences between the adult and paediatric disease. Furthermore, subclassifications within the childhood age group can be made depending on age at diagnosis and tumour site. However, challenges remain on how to reconcile clinical data from adult patients to tailor novel treatment strategies specifically for paediatric patients.

Potential role for valproate in the treatment of high--risk brain tumors of childhood-results from a retrospective observational cohort study

Although substantial progress has been made in pediatric brain tumor management, patients with brainstem tumors and high-grade gliomas, as well as patients less than 3 years of age with high-risk malignant tumors, have a poorer prognosis. The authors have been treating these patients with radiotherapy and standard carboplatin and vincristine chemotherapy. Since January 2007 the authors have been using valproate as anticonvulsant for prophylaxis. The authors performed a retrospective cohort analysis of pediatric patients with high-risk brain tumors treated with chemotherapy, radiotherapy, and valproate prophylaxis, comparing this group with a historical control. The 2007-2008 group was comprised of 22 patients, 15 with brainstem tumors (7 diffuse intrinsic pontine glioma [DIPG], 3 focal, the remaining infiltrating with a solid portion), 4 with diencephalic tumors (2 thalamic), and 3 with supratentorial high-grade tumors (1 glioblastoma, 1 recurrent grade III ependymoma, 1 with gliomatosis). There were 15 patients alive (68%) after a mean follow-up time of 19 months. Survival function comparison by log rank test was highly significant (P = .004) with a hazard ratio of 0.31 (0.14-0.70). Radiological response showed 3 complete responses (14%), 8 partial responses (36%), 5 stable diseases (23%), and 5 progresssive diseases (23%). The authors hypothesize that valproate may have potentiated the antiangiogenic effect of vincristine, diminished expression of resistance to carboplatin, and sensitized tumor cells to radiotherapy. The authors suggest that clinical trials of carboplatin and vincristine associated with oral continuous low-dose valproate are indicated for pediatric patients with high-risk brain tumor.

Diffuse intrinsic pontine glioma-current status and future strategies

INTRODUCTION

Diffuse intrinsic pontine gliomas which constitute 15% of all childhood brain tumors are inoperable and response to radiation and chemotherapy has not improved long-term survival. Due to lack of newer effective therapies, mean survival after diagnosis has remained less than 12 months. Trials investigating chemotherapy and/or radiation have proven disappointing. As biopsy of these tumors are rarely performed due to the high eloquence of the brain stem, information about the pathology and biology remains elusive hindering development of novel biologic agents. Poor access of most chemotherapeutic agents to these tumors due to the blood-brain barrier continues to undermine therapeutic efficacy. Thus, to date, we remain at a virtual standstill in our attempts to improve the prognosis of children with these tumors.

METHODS

An extensive review of the literature was performed concerning children with diffuse brain stem gliomas including clinical trials, evolving molecular biology, and newer therapeutic endeavors.

CONCLUSION

A pivotal approach in improving the prognosis of these tumors should include the initiation of biopsy and encouraging families to consider autopsy to study the molecular biology. This will help in redefining this tumor by its molecular signature and profiling targeted therapy. Continued advances should be pursued in neuroimaging technology including identifying surrogate markers of early disease progression. Defining strategies to enhance local delivery of drugs into tumors with the help of newer surgical techniques are important. Exhaustive research in all these aspects as a multidisciplinary approach could provide hope to children with these fatal tumors.

Multidisciplinary management of childhood brain tumors: a review of outcomes, recent advances, and challenges

OBJECT

Brain tumors are the most common category of childhood solid tumors. In the 1970s and 1980s, treatment protocols for benign tumors focused almost exclusively on surgery, with radiation treatment as a salvage modality, whereas the management of malignant tumors employed a combination of surgery, radiation therapy, and chemotherapy, with therapeutic approaches such as "8-in-1" chemotherapy often applied across histological tumor subsets that are now recognized to be prognostically distinct. During the ensuing years, treatment has become increasingly refined, based on clinical and, more recently, molecular factors, which have supported risk-adapted treatment stratification. The goal of this report is to provide an overview of recent progress in the field.

METHODS

A review of the literature was undertaken to examine recent advances in the management of the most common childhood brain tumor subsets, and in particular to identify instances in which molecular categorization and treatment stratification offer evidence or promise for improving outcome.

RESULTS

For both medulloblastomas and infant tumors, refinements in clinical and molecular stratification have already facilitated efforts to achieve risk-adapted treatment planning. Current treatment strategies for children with these tumors focus on improving outcome for tumor subsets that have historically been relatively resistant to therapy and reducing treatment-related sequelae for children with therapy-responsive tumors. Recent advances in molecular categorization offer the promise of further refinements in future studies. For children with ependymomas and low-grade gliomas, clinical risk stratification has facilitated tailored approaches to therapy, with improvement of disease control and concomitant reduction in treatment sequelae, and recent discoveries have identified promising therapeutic targets for molecularly based therapy. In contrast, the prognosis remains poor for children with diffuse intrinsic pontine gliomas and other high-grade gliomas, despite recent identification of biological correlates of tumor prognosis and elucidation of molecular substrates of tumor development.

CONCLUSIONS

Advances in the clinical and molecular stratification for many types of childhood brain tumors have provided a foundation for risk-adapted treatment planning and improvements in outcome. In some instances, molecular characterization approaches have also yielded insights into new therapeutic targets. For other tumor types, outcome remains discouraging, although new information regarding the biological features critical to tumorigenesis are being translated into novel therapeutic approaches that hold promise for future improvements.

Surgical management of tumors producing the thalamopeduncular syndrome of childhood

OBJECT

Thalamopeduncular tumors arise at the junction of the inferior thalamus and cerebral peduncle and present with a common clinical syndrome of progressive spastic hemiparesis. Pathologically, these lesions are usually juvenile pilocytic astrocytomas and are best treated with resection with the intent to cure. The goals of this study are to define a common clinical syndrome produced by thalamopeduncular tumors and to discuss imaging characteristics as well as surgical adjuncts, intraoperative nuances, and postoperative complications relating to the resection of these neoplasms.

METHODS

The authors present a retrospective review of their experience with 10 children presenting between 3 and 15 years of age with a thalamopeduncular syndrome. Formal preoperative MR imaging was obtained in all patients, and diffusion tensor (DT) imaging was performed in 9 patients. Postoperative MR imaging was obtained to evaluate the extent of tumor resection. A prospective analysis of clinical outcomes was then conducted by the senior author.

RESULTS

Pilocytic astrocytoma was the pathological diagnosis in 9 cases, and the other was fibrillary astrocytoma. Seven of 9 pilocytic astrocytomas were completely resected. Radical surgery was avoided in 1 child after DT imaging revealed that the corticospinal tract (CST) coursed through the center of the tumor, consistent with the infiltrative nature of fibrillary astrocytoma as identified by stereotactic biopsy. In 8 patients, tractography served as an important adjunct for designing a surgical approach that spared the CST. In 6 cases the CSTs were pushed anterolaterally, making a transsylvian approach a poor choice, as was evidenced by the first patient in the series, who underwent operation prior to the advent of tractography, and who awoke with a dense contralateral hemiparesis. Thus, subsequent patients with this deviation pattern underwent a transcortical approach via the middle temporal gyrus. One patient exhibited medial deviation of the tracts and another had lateral deviation, facilitating a transtemporal and a transfrontal approach, respectively.

CONCLUSIONS

The thalamopeduncular syndrome of progressive spastic hemiparesis presenting in children with or without symptoms of headache should alert the examiner to the possibility of a tumoral involvement of CSTs. Preoperative tractography is a useful adjunct to surgical planning in tumors that displace motor pathways. Gross-total resection of pilocytic astrocytomas usually results in cure, and therefore should be entertained when developing a treatment strategy for thalamopeduncular tumors of childhood.

Temozolomide in the treatment of children with newly diagnosed diffuse intrinsic pontine gliomas: a report from the Children's Oncology Group

An open-label phase II study (ACNS0126) testing the efficacy of chemoradiotherapy with temozolomide (TMZ) followed by adjuvant TMZ was conducted by the Children's Oncology Group. During the period from July 6, 2004 through September 6, 2005, 63 children with newly diagnosed diffuse intrinsic pontine glioma (DIPG) were enrolled in the study. All patients received TMZ at a dosage of 90 mg/m(2)/day for 42 days to a dose of 59.4 Gy. Four weeks following irradiation, TMZ was given at a dosage of 200 mg/m(2)/day for 5 days every 28 days, for a total of 10 cycles. The primary objective of the statistical analysis was to determine whether the current treatment produced a 1-year event-free survival (EFS) rate higher than the historical baseline of 21.9% observed in CCG-9941. The mean 1-year EFS (± standard deviation) was 14% ± 4.5%, compared with 21.9% ± 5% for CCG-9941. The P value of the test of comparison of 1-year EFS, based on a 1-sided, 1-sample test of proportions, was .96. There was no evidence that temozolomide produced a 1-year EFS rate higher than 21.9%. The mean 1-year OS (± standard deviation) was 40% ± 6.5%, compared with 32% ± 6% for CCG-9941. The median time to death was 9.6 months. Chemoradiotherapy with TMZ followed by adjuvant TMZ is not more effective than previously reported regimens for the treatment of children with DIPG.

The addition of high-dose tamoxifen to standard radiotherapy does not improve the survival of patients with diffuse intrinsic pontine glioma

The study aimed to examine the tolerability of the combination of radiotherapy and tamoxifen and the effect on median and event free survival as well as collecting data on the use of steroids in this population. 31 patients with diffuse intrinsic pontine glioma, diagnosed on clinical and radiological criteria, were treated with high-dose oral tamoxifen (120 mg/m(2)/day) given concomitantly with standard dose radiotherapy (54 Gy in 1.8 Gy fractions over 6 weeks). Results Tamoxifen was well tolerated with no grade 3 or 4 CTC toxicity reported. At 1 year, the progression free and event free survival were 3.2% (95% CI: 0.2-14.1%), and at 6 months 19.4% (CI: 7.9% to 34.6%). The overall survival at 1 year was 16.1% (CI: 5.9-30.9%) with median survival 6.32 months. In this study, in which tamoxifen was used in conjunction with radiotherapy, progression free survival was shown to be less good when compared with historical data HR = 3.1 (CI: 1.7-5.7). There was no significant reduction in overall survival. The addition of high-dose tamoxifen, although well tolerated, confers no clinical benefit to patients treated with diffuse intrinsic pontine glioma treated with standard radiotherapy.

Prospective evaluation of radiotherapy with concurrent and adjuvant temozolomide in children with newly diagnosed diffuse intrinsic pontine glioma

PURPOSE

To present outcome data in a prospective study of radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ) in children with diffuse intrinsic pontine gliomas (DIPGs).

METHODS AND MATERIALS

Pediatric patients with newly diagnosed DIPGs were prospectively treated with focal RT to a dose of 54 Gy in 30 fractions along with concurrent daily TMZ (75 mg/m(2), Days 1-42). Four weeks after completing the initial RT-TMZ schedule, adjuvant TMZ (200 mg/m(2), Days 1-5) was given every 28 days to a maximum of 12 cycles. Response was evaluated clinically and radiologically with magnetic resonance imaging and positron emission tomography scans.

RESULTS

Between March 2005 and November 2006, 20 children (mean age, 8.3 years) were accrued. Eighteen patients have died from disease progression, one patient is alive with progressive disease, and one patient is alive with stable disease. Median overall survival and progression-free survival were 9.15 months and 6.9 months, respectively. Grade III/IV toxicity during the concurrent RT-TMZ phase included thrombocytopenia in 3 patients, leucopenia in 2, and vomiting in 7. Transient Grade II skin toxicity developed in the irradiated fields in 18 patients. During the adjuvant TMZ phase, Grade III/IV leucopenia developed in 2 patients and Grade IV thrombocytopenia in 1 patient. Patients with magnetic resonance imaging diagnosis of a high-grade tumor had worse survival than those with a low-grade tumor (p = 0.001). Patients with neurologic improvement after RT-TMZ had significantly better survival than those who did not (p = 0.048).

CONCLUSIONS

TMZ with RT has not yielded any improvement in the outcome of DIPG compared with RT alone. Further clinical trials should explore novel treatment modalities.

Treatment of diffuse intrinsic brainstem gliomas: failed approaches and future strategies

Diffuse intrinsic pontine gliomas constitute ~ 60-75% of tumors found within the pediatric brainstem. These malignant lesions present with rapidly progressive symptoms such as cranial nerve, long tract, or cerebellar dysfunctions. Magnetic resonance imaging is usually sufficient to establish the diagnosis and obviates the need for surgical biopsy in most cases. The prognosis of the disease is dismal, and the median survival is < 12 months. Resection is not a viable option. Standard therapy involves radiotherapy, which produces transient neurological improvement with a progression-free survival benefit, but provides no improvement in overall survival. Clinical trials have been conducted to assess the efficacy of chemotherapeutic and biological agents in the treatment of diffuse pontine gliomas. In this review, the authors discuss recent studies in which systemic therapy was administered prior to, concomitantly with, or after radiotherapy. For future perspective, the discussion includes a rationale for stereotactic biopsies as well as possible therapeutic options of local chemotherapy in these lesions.

Diagnostic and therapeutic stratification of childhood brain tumors: implications for translational research

Recent advances in the categorization of childhood brain tumors have improved risk-based treatment planning. In several instances, new therapeutic strategies that incorporate these advances have resulted in meaningful improvements in progression-free and overall survival. Current studies are directed at further refining therapy based on clinical, biological, and molecular data; testing the effectiveness of a number of novel therapeutic strategies for high-risk tumors; and examining approaches to reduce sequelae of treatment among more favorable-risk tumor subsets. Because multiple tumor subtypes are individually relatively uncommon, most such studies are being conducted by large co-operative groups, such as the Children's Oncology Group, or by smaller brain tumor-focused consortia, such as the Pediatric Brain Tumor Consortium.

Preradiation chemotherapy may improve survival in pediatric diffuse intrinsic brainstem gliomas: final results of BSG 98 prospective trial

Radiation therapy remains the only treatment that provides clinical benefit to children with diffuse brainstem tumors. Their median survival, however, rarely exceeds 9 months. The authors report a prospective trial of frontline chemotherapy aimed at delaying radiation until time of clinical progression. The aim was to investigate the possibility that radiotherapy would maintain its activity in children whose disease progressed after chemotherapy. Twenty-three patients took part in this protocol, the BSG 98 protocol, which consisted of frontline chemotherapy alternating hematotoxic and nonhematotoxic schedules. Each cycle included three courses delivered monthly; the first course was 1,3-bis(2-chloroethyl)-1-nitrosoureacisplatin, and the second and third were high-dose methotrexate. Three patients underwent one cycle; 5 patients each, two and three cycles; and 10 patients, four cycles. Twenty of the 23 patients eventually received local radiation therapy. A historical cohort of 14 patients who received at least local radiation therapy served as controls. Four patients experienced severe iatrogenic infections, and 11 patients required platelet transfusions. Median survival increased significantly in patients participating in the protocol compared to that in the historical controls (17 months, 95% confidence interval [CI], 10-23 months, vs. 9 months, 95% CI, 8-10 months; p = 0.022), though hospitalization was prolonged (57 vs. 25 days, p = 0.001). Although frontline chemotherapy alternating hematotoxic and nonhematotoxic schedules significantly increases overall median survival, its cost from infection and hospitalization deserves honest discussion with the children and their parents.

Concurrent radiotherapy with temozolomide followed by adjuvant temozolomide and cis-retinoic acid in children with diffuse intrinsic pontine glioma

The prognosis of children with diffuse intrinsic pontine glioma (DIPG) is very poor. Radiotherapy remains the standard treatment for these patients, but the median survival time is only 9 months. Currently, the use of concurrent radiotherapy with temozolomide (TMZ) has become the standard care for adult patients with malignant gliomas. We therefore investigated this approach in 12 children diagnosed with DIPG. The treatment protocol consisted of concurrent radiotherapy at a dose of 55.8-59.4 Gy at the tumor site with TMZ (75 mg/m(2)/day) for 6 weeks followed by TMZ (200 mg/m(2)/day) for 5 days with cis-retinoic acid (100 mg/m(2)/day) for 21 days with a 28-day cycle after concurrent radiotherapy. Ten of the 12 patients had a clinical response after the completion of concurrent radiotherapy. Seven patients had a partial response, four had stable disease, and one had progressive disease. At the time of the report, 9 of the 12 patients had died of tumor progression, one patient was alive with tumor progression, and two patients were alive with continuous partial response and clinical improvement. The median time to progression was 10.2 +/- 3.0 months (95% confidence interval [CI], 4.2-16.1 months). One-year progression-free survival was 41.7% +/- 14.2%. The median survival time was 13.5 +/- 3.6 months (95% CI, 6.4-20.5 months). One-year overall survival was 58% +/- 14.2%. The patients who had a partial response after completion of concurrent radiotherapy had a longer survival time (p = 0.036) than did the other patients (those with stable or progressive disease). We conclude that the regimen of concurrent radiotherapy and TMZ should be considered for further investigation in a larger series of patients.

Treatment of children with diffuse intrinsic brain stem glioma with radiotherapy, vincristine and oral VP-16: a Children's Oncology Group phase II study

BACKGROUND

The prognosis for children with brain stem glioma remains grim. Based on studies suggesting efficacy of vincristine and oral VP-16, The Pediatric Oncology Group (POG, now part of the Children's Oncology Group) conducted a study using these agents in combination with standard external beam radiation for children with newly diagnosed brain stem glioma.

METHODS

Children were eligible for the study if they 3-21 years of age, had MRI-evidence of a diffuse intrinsic pontine glioma, and had neurologic deficits of <6 months duration. Patients received local radiotherapy to a dosage of 54 Gy. Chemotherapy consisted of two 28-day cycles of vincristine, 1.5 mg/m(2), days 1, 8, and 15 and oral VP-16, 50 mg/m(2), days 1-21, starting concurrent with radiation, and continuing for ten cycles following radiation.

RESULTS

Of the 31 children enrolled, 30 were eligible and evaluable for survival and toxicity. Their median age was 8 years (range 3-14 years). Seven patients (23%) had a partial response following radiation, 18 (60%) had stable disease, 2 (7%) had progressive disease, and response in 3 patients (10%) was not measured. All 30 children have died. Overall survival at 1 year was 27 +/- 7% and at 2 years, 3 +/- 2%. The median survival was 9 months (range 3-36 months). Hematologic toxicity was significant; other toxicities included constipation, mucositis, emesis, and infection.

CONCLUSION

The addition of vincristine and oral VP-16 to standard external beam radiation causes moderate toxicity and does not improve survival of children with diffuse intrinsic brain stem glioma.

Concurrent carbogen and radiation therapy in children with high-risk brainstem gliomas

In an attempt to improve local control, we assessed the feasibility of the addition of 4 min of carbogen inhalation (as a radiosensitizer) to daily fractionated radiotherapy in pediatric patients with high grade and/or diffuse brainstem gliomas. Ten patients inhaled carbogen for >90% of the radiation treatments. Median survival time from start of therapy was 0.80 years. Carbogen inhalation did not appear to improve the dismal prognosis.

Molecular and cellular response of the most extensively used rodent glioma models to radiation and/or cisplatin

Purpose Anti-glioma strategies are generally based on trials involving rodent models whose choice remains based on proliferative capacity and availability. Recently, our group obtained the most protracted survival of rats bearing F98 gliomas by combining synchrotron X-rays and intracerebral cisplatin injection (Biston et al., Cancer Res, 64:2317-2323, 2004). The response to such treatment was suggested to be dependent on BRCA1, a tumour suppressor known to be involved in the response to radiation and cisplatin. In order to verify the impact of BRCA1 functionality upon success of anti-glioma trials, radiobiological features and BRCA1-dependent stress signalling were investigated in the most extensively used rodent glioma models. Methods Cell death pathways, cell cycle arrests, DNA repair and stress signalling were evaluated in response to radiation and cisplatin in C6, 9L and F98 models. Results Rodent glioma models showed a large spectrum of cellular radiation response. Surprisingly, BRCA1 was found to be functionally impaired in C6 and F98 favouring genomic instability, tumour heterogeneity and tolerance of unrepaired DNA damage. Significance Our findings strengthened the importance of the choice of the glioma model on genetic and radiobiological bases, inasmuch as all these rat glioma models are induced by nitrosourea-mediated mutagenesis that may favour specific gene mutations. Particularly, BRCA1 status may condition the response to anti-glioma treatments. Furthermore, since BRCA1 acts as a tumour suppressor in a number of malignancies, our findings raise also the question of the implication of BRCA1 in brain tumours formation.

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.

Diffuse and focal brain stem tumors in childhood: prognostic factors and surgical outcome. Experience in a single institution

OBJECTIVE

Brainstem tumors (BSTs) are usually gliomas and are divided into diffuse BSTs (DBSTs) and focal BSTs (FBSTs). The aim of this study is to investigate the different outcomes of these two entities.

METHODS

Thirty-one patients with BSTs were admitted to our institution from 1995 to 2003. Patients with DBSTs were treated with locoregional radiotherapy (1.8 Gy/day for 54 Gy) and weekly vincristine for radiosensitization (1.5 mg/sm for six total doses). Patients with FBSTs underwent surgical resection. Chemotherapy and/or radiotherapy were considered in progression.

RESULTS AND CONCLUSIONS

Fourteen patients were diagnosed as having DBSTs. The responses to treatment were ten cases of partial response, three of stable disease, and one of progressive disease. General and/or neurological symptoms improved in more than 80% of patients. The median time from diagnosis to progression and to death were, nonetheless, 8 (range of 3-13) and 13 (range of 4-25) months, respectively, with a 2-year overall survival rate of 12.3% [standard error (SE) 11.2]. Seventeen patients were diagnosed as having FBSTs. Gross total removal was achieved in 4/17 cases, subtotal removal in 7/17, and partial removal in 6/17. There was one surgery-related death. Eight out of 17 patients had adjuvant chemo- and/or radiotherapy after progression: 6/8 are without neurological symptoms and 2/8 have died due to tumor progression. The 4-year overall and disease-free survival rates are 87.4 (SE 8.4) and 58.8% (SE 11.9), respectively, the extent of resection being the most important prognostic factor (p=0.012). DBSTs continue to carry a dismal prognosis, thus demanding new treatment modalities; FBSTs can be treated surgically and patients benefit from a better prognosis.

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.

Diffuse brainstem glioma in children: critical review of clinical trials

Diffuse intrinsic brainstem gliomas constitute 15-20% of all CNS tumours in children, and are the main cause of death in children with brain tumours. Many clinical trials have been done over the past three decades, but survival has remained static. More than 90% of children die within 2 years of diagnosis, and conventional fractionated radiation remains the standard treatment. However, median survival differs substantially between clinical trials, suggesting a survival benefit with some strategies. We appraised the consistency between protocols in terms of eligibility criteria, definition and assessment of response and progression, statistical design, and endpoints. Study designs varied substantially, which could explain the differences in outcome, and no treatment has shown a benefit over conventional radiotherapy. However, consistency between protocols (eg, eligibility criteria and outcome measures) is important to measure the progress in management of diffuse pontine gliomas.

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.

A Phase I study of concurrent RMP-7 and carboplatin with radiation therapy for children with newly diagnosed brainstem gliomas

BACKGROUND

Ninety percent of children with diffuse, intrinsic brainstem tumors will die within 18 months of diagnosis. Radiotherapy is of transient benefit to these children, and a potential way to improve its efficacy is to add radiosensitizers. Carboplatin is antineoplastic and radiosensitizing; however, its delivery to the primary tumor site is problematic. RMP-7 is a bradykinin analog that causes selective permeability of the blood-brain-tumor interface. The objective of this Phase I study was to determine the toxicity and feasibility of delivering RMP-7 and carboplatin for 5 successive days during radiotherapy to children with newly diagnosed, diffuse, intrinsic brainstem gliomas.

METHODS

RMP-7 was given prior to the end of carboplatin infusion. Local radiotherapy, in dose fractions of 180 centigrays (cGy) per day (to a total dose of 5940 cGy), was given within 4 hours of completion of drug delivery. Duration of treatment was escalated in a stepwise, weekly fashion in cohorts of 3 patients, until there was treatment-limiting toxicity or until radiotherapy was completed. Thirteen patients were treated, and their median age was 7 years (age range, 3-12 yrs).

RESULTS

One child died early during treatment of progressive disease and was not assessable for toxicity. Treatment for 3 weeks, 4 weeks, and 5 weeks was tolerated well, with mild flushing, tachycardia, nausea, emesis, dizziness, and abdominal pain. One of 3 children treated at the full duration of therapy (33 doses over 7 weeks) developed dose-limiting hepatotoxicity and neutropenia. The estimated median survival was 328 days, and 1 patient remained free of disease progression for > 400 days after the initiation of treatment.

CONCLUSIONS

The results of this study confirmed the feasibility of giving RMP-7 and carboplatin daily during radiotherapy to children with brainstem tumors.

Phase 1 study of concurrent RMP-7 and carboplatin with radiotherapy for children with newly diagnosed brainstem gliomas

BACKGROUND

Ninety percent of children with diffuse intrinsic brainstem tumors will die within 18 months of diagnosis. Radiotherapy is of transient benefit, and one way to potentially improve its efficacy is to add radiosensitizers. Carboplatin is antineoplastic and radiosensitizing. However, delivery to the primary tumor site is problematic. RMP-7 is a bradykinin analog that causes selective permeability of the blood-brain-tumor interface. The goal of the current Phase I study was to determine the toxicity and feasibility of delivering RMP-7 and carboplatin for 5 successive days during radiotherapy.

METHODS

RMP-7 was given before the end of carboplatin infusion. Local radiotherapy (5940 centigrays) was given within 4 hours of completion of drug delivery. Duration of treatment was escalated in a stepwise, weekly fashion, in cohorts of 3, until there was treatment-limiting toxicity or until radiotherapy was completed. Thirteen patients were treated, whose median age was 7 years (range, 3-14 yrs).

RESULTS

One child died early in treatment of progressive disease and was not assessable for toxicity. Treatment for 3, 4, or 5 weeks was tolerated well, with mild flushing, tachycardia, nausea, emesis, dizziness, and abdominal pain. Of 3 children treated at the full duration of therapy (33 doses over 7 wks), 1 developed dose-limiting hepatotoxicity and neutropenia. The estimated median survival period was 328 days, and 1 patient remained disease progression free > 400 days from initiation of treatment.

CONCLUSIONS

The results of the current study confirmed the feasibility of giving RMP-7 and carboplatin daily during radiotherapy.

Gross total surgical removal of malignant glioma from the medulla oblongata: report of two adult cases with reference to surgical anatomy

Surgery was performed on the medulla oblongata of two adult patients with malignant glioma. Gross total resection of the tumors, located laterally or medially in the upper half of the medulla respectively, was achieved. The patient with the medially located tumor experienced significant postoperative neurological deterioration including sleep apnea. The other patient with the laterally located tumor showed symptomatic improvement without respiratory complications. The patient with an anaplastic astrocytoma survived approximately 4 years and the patient with a glioblastoma multiforme approximately 2 years. Although the upper half of the medulla is more critical than the lower half, a lateral approach to the upper half of the medulla appears to be relatively safer than a medial approach. Some cases of focal malignant gliomas in the medulla may be amenable to gross total resection in order to achieve improved outcome. Surgery can be undertaken when a tumor is unilateral and its margin appears relatively clear on magnetic resonance images.

Prolonged convection-enhanced delivery into the rat brainstem

OBJECTIVE

Prolonged convection-enhanced delivery was used in an attempt to achieve large volumes of distribution (V(d)) in the rat brainstem. Clinical assessment and histological analysis were performed to establish the safety of this approach.

METHODS

For evaluation of V(d,), 10 rats underwent stereotactic cannula placement into the brainstem. Five rats underwent a 24-hour infusion (volume of infusion [V(i)], 200 microl), and 5 rats underwent a 7-day infusion (V(i), 2 ml) of fluorescein isothiocyanate-dextran. Serial brainstem sections were imaged with ultraviolet illumination, and V(d) was assessed. For assessment of clinical tolerance, 30 additional rats underwent chronic infusions of an isotonic saline solution into the brainstem. Serial neurological examinations were performed, followed by histological analysis after the animals' death.

RESULTS

No animal demonstrated clinically recognized neurological deficits. Foci of organizing necrosis were limited to the site of infusion and cannula tract. V(d) increased linearly with increasing V(i) (range, 24.8-130.6 mm(3)). Maximal cross sectional area of fluorescence and craniocaudal extent of fluorescence increased with increasing V(i). Fluorescence was detected throughout the entire brainstem beyond the compact area of highly concentrated tracer.

CONCLUSION

Prolonged convection-enhanced delivery can be applied safely in the rat brainstem with no recognized limitations of V(d) and minimal histological changes beyond the site of infusion. Chronic brainstem infusions may enhance the potential application of convection-enhanced delivery for therapeutic purposes in treating diffuse pontine gliomas.

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.

Preradiation chemotherapy in primary high-risk brainstem tumors: phase II study CCG-9941 of the Children's Cancer Group

PURPOSE

This Children's Cancer Group group-wide phase II trial evaluated the efficacy and toxicity of two chemotherapy arms administered before hyperfractionated external-beam radiotherapy (HFEBRT).

PATIENTS AND METHODS

Thirty-two patients with newly diagnosed brainstem gliomas were randomly assigned to regimen A and 31 to regimen B. Regimen A comprised three courses of carboplatin, etoposide, and vincristine; regimen B comprised cisplatin, etoposide, cyclophosphamide, and vincristine. Both arms included granulocyte colony-stimulating factor. Patients were evaluated by magnetic resonance imaging after induction chemotherapy and HFEBRT at a dose of 72 Gy.

RESULTS

Ten percent +/- 5% of regimen A patients objectively responded to chemotherapy. For combined induction and radiotherapy, 27% +/- 9% of patients improved. The neuroradiographic response rate for regimen B was 19% +/- 8% for chemotherapy and 23% +/- 9% after HFEBRT. Response rates were not statistically significant between regimens after induction or chemotherapy/HFEBRT. Event-free survival was 17% +/- 5% (estimate +/- SE) at 1 year and 6% +/- 3% at 2 years. Survival was significantly longer among patients who responded to chemotherapy (P <.05). Among patients who received regimen A induction, grades 3 and 4 leukopenia were observed in 50% to 65%, with one toxicity-related death. For regimen B, severe leukopenia occurred in 86% to 100%, with febrile neutropenia in 48% to 60% per course.

CONCLUSION

Neither chemotherapy regimen meaningfully improved response rate, event-free survival, or overall survival relative to previous series of patients with brainstem gliomas who received radiotherapy with or without chemotherapy.

Effect of hyperosmolar mannitol on convection-enhanced delivery into the rat brain stem

INTRODUCTION

Convection-enhanced delivery (CED) can safely achieve high local infusate concentrations within the rat brain stem with predictable distribution volumes. The authors investigated the effects of co-infusion or systemic administration of hyperosmolar mannitol on distribution parameters for infusions into the rat brain stem.

METHODS

Fifteen rats underwent stereotactic cannula placement into the pontine nucleus oralis (PnO) followed by infusions at a constant rate to a total volume of 1 microl. Five rats underwent infusion of fluorescein isothiocyanate (FITC)-dextran diluted in 20% mannitol. Five rats received an intraperitoneal injection of 20% mannitol 10 min prior to infusion of FITC-dextran diluted in isotonic saline. As a control group, 5 rats underwent infusion of FITC-dextran diluted in isotonic saline without mannitol administration. Serial brain sections were imaged using confocal microscopy with ultraviolet illumination, and distribution volume (Vd) was calculated by computer image analysis. Histologic analysis was performed on adjacent sections.

RESULTS

Volumes of distribution were not significantly increased by co-infusion of mannitol directly into the brain stem or by systemic mannitol administration compared to infusion without mannitol. Similarly, mannitol administration by either means failed to significantly alter maximal cross-sectional area or cranio-caudal extent of fluorescence. No animal demonstrated a postoperative neurological deficit or histologic evidence of tissue disruption.

CONCLUSIONS

Neither systemic administration nor co-infusion of hyperosmolar mannitol significantly affects distribution parameters for CED infusions into the rat brain stem.