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

Molecular Biology in Pediatric High-Grade Glioma: Impact on Prognosis and Treatment

High-grade gliomas are the main cause of death in children with brain tumours. Despite recent advances in cancer therapy, their prognosis remains poor and the treatment is still challenging. To date, surgery followed by radiotherapy and temozolomide is the standard therapy. However, increasing knowledge of glioma biology is starting to impact drug development towards targeted therapies. The identification of agents directed against molecular targets aims at going beyond the traditional therapeutic approach in order to develop a personalized therapy and improve the outcome of pediatric high-grade gliomas. In this paper, we critically review the literature regarding the genetic abnormalities implicated in the pathogenesis of pediatric malignant gliomas and the current development of molecularly targeted therapies. In particular, we analyse the impact of molecular biology on the prognosis and treatment of pediatric high-grade glioma, comparing it to that of adult gliomas.

Pediatric Brain Tumors: Innovative Genomic Information Is Transforming the Diagnostic and Clinical Landscape

Pediatric neuro-oncology has undergone an exciting and dramatic transformation during the past 5 years. This article summarizes data from collaborative group and institutional trials that have advanced the science of pediatric brain tumors and survival of patients with these tumors. Advanced genomic analysis of the entire spectrum of pediatric brain tumors has heralded an era in which stakeholders in the pediatric neuro-oncology community are being challenged to reconsider their current research and diagnostic and treatment strategies. The incorporation of this new information into the next-generation treatment protocols will unleash new challenges. This review succinctly summarizes the key advances in our understanding of the common pediatric brain tumors (ie, medulloblastoma, low- and high-grade gliomas, diffuse intrinsic pontine glioma, and ependymoma) and some selected rare tumors (ie, atypical teratoid/rhabdoid tumor and CNS primitive neuroectodermal tumor). The potential impact of this new information on future clinical protocols also is discussed. Cutting-edge genomics technologies and the information gained from such studies are facilitating the identification of molecularly defined subgroups within patients with particular pediatric brain tumors. The number of evaluable patients in each subgroup is small, particularly in the subgroups of rare diseases. Therefore, international collaboration will be crucial to draw meaningful conclusions about novel approaches to treating pediatric brain tumors.

Diffuse intrinsic pontine glioma: time for therapeutic optimism

Diffuse intrinsic pontine glioma (DIPG) is an aggressive tumor that is universally fatal, and to-date we are at a virtual standstill in improving its grim prognosis. Dearth of tissue due to rarity of biopsy has precluded understanding the elusive biology and frustration continues in reproducing faithful animal models for translational research. Furthermore the intricate anatomy of the pons has forestalled locoregional therapy and drug penetration. Over the last few years, biopsy-driven targeted therapy, development of vitro and xenograft animal models for therapeutic testing, profiling immunotherapeutic strategies and locoregional infusion of drugs in brain stem tumors, now provide a sense of hope in the years ahead. This review aims to discuss current status and advances in the management of these tumors.

Managing teenage/young adult (TYA) brain tumors: a UK perspective

Tumors of the CNS are among the commonest malignancies occurring in teenage/young adult patients (i.e., those aged between 15 and 24 years). The treatment of this patient population is challenging. Adolescence and young adulthood are a turbulent period of life, with physical, emotional, social and cognitive changes. Best practice advocates their treatment in dedicated teenage/young adult units, with multidisciplinary team input and access to clinical trials. Treatment of CNS malignancies is dependent upon histological subtype and staging, with varying combinations of surgery, radiotherapy and chemotherapy used. Clinical trials directly targeted at this patient population are rare; treatments are based on pediatric protocols as studies have demonstrated improved outcomes in patients (with other malignancies) treated as such. Scope for improvement lies in minimizing patient risk of recurrence and long-term sequelae of treatment. Molecular characterization of tumors may provide further information.

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.

Application of technical strategies for surgical management of adult intrinsic pontine gliomas: a retrospective series

OBJECT

The authors retrospectively analyzed the surgical treatment of adult intrinsic pontine gliomas in their department, and to enhance the understanding of technical strategies to treat this disease.

METHODS

7 patients with intrinsic pontine gliomas were recruited for this study, between January 2011 and June 2013. All patients underwent preoperative MRI and Diffusion Tensor Imaging Fiber Tracking (DTI-FT). In addition, multimodal Intraoperative Neuromonitoring (IOM) and Intraoperative Neuronavigation were also applied during microsurgery.

RESULTS

7 patients with intrinsic pontine gliomas were treated at the West China Hospital of Sichuan University. Mean age, mean duration of symptoms prior to diagnosis, and mean duration of follow-up average time were 38.0 years, 2.0 months, and 23.4 months, respectively. The main presentations were progressive cranial nerve deficits and long tract signs. Total resection was achieved in 3 patients, subtotal resection in 2, and partial resection in 2. Postoperative pathological examination revealed: astrocytoma (WHO II) in 4 cases, anaplastic oligoastrocytoma (AO, WHO III) in one case, and anaplastic astrocytoma (AA, WHO III) in two cases. Postoperative radiotherapy were administered to all patients, and 4 patients with astrocytoma (WHO II) rejected chemotherapy. After 11-39 months of follow-up, patient symptoms were resolved or stable without aggravation except one patient died because of rapidly progressive glioma at 11 months after operation. MRI in other patients showed residual tumor size to be unchanged or without obviously recurrence.

CONCLUSION

Combining preoperative MRI with preoperative DTI-FT, surgery can be better assessed and the operation for adult intrinsic pontine gliomas can be maximally and safely resected with the aid of Multimodal IOMs and Intraoperative Navigation during microsurgery.

Diffuse intrinsic pontine glioma biopsy: a single institution experience

Tumor biopsy is rarely performed in diffuse intrinsic pontine glioma (DIPG) due to the presumed risk of surgical complications, although data on the surgery related morbidity of DIPG biopsy is sparse. We performed a retrospective review on 22 consecutive cases of DIPG diagnosed from 2002 to 2012 at Children's Hospital of Michigan, 15 of which underwent biopsy. Transient new or worsening neurological deficits were observed in three of 15 cases following surgery. No surgery related mortality or permanent deficit was observed, and the mean overall survival was 10.4 ± 3.8 months. Undergoing biopsy did not adversely affect the outcome.

Temozolomide in the treatment of newly diagnosed diffuse brainstem glioma in children: a broken promise?

BACKGROUND

The purpose of this study was to assess the efficacy and toxicity of radiotherapy (RT) with concurrent temozolomide (TMZ) chemotherapy followed by adjuvant TMZ in children with diffuse intrinsic pontine glioma (DIPG).

METHODS

Patients younger than 18 years with newly diagnosed DIPG were enrolled. Children were treated with focal RT along with concurrent daily TMZ. Four weeks after completing the initial RT-TMZ schedule, adjuvant TMZ was given every 28 days up to 12 cycles or progression disease.

RESULTS

Fifteen children with a median age of 9 years were enrolled. Fourteenth out of the 15 patients completed the chemoradiotherapy. The toxicity associated with TMZ was primarily haematopoietic. At a median follow-up of 15 months 13 children had died and 2 children were alive with progressive disease. No patient experienced complete response (CR). The median time to progression was 7.15 months.

CONCLUSION

Chemoradiotherapy with TMZ followed by adjuvant TMZ did not improve the poor prognosis associated with DIPG in children.

A twenty-year review of diagnosing and treating children with diffuse intrinsic pontine glioma in The Netherlands

INTRODUCTION

Children with diffuse intrinsic pontine glioma (DIPG) face a dismal prognosis, with a median overall survival of 9 months. Our aims are to determine the incidence of DIPG in the Netherlands and to identify points for improvement in clinical research, a prerequisite for increasing the chance to find a cure.

METHODS

We performed a population-based retrospective cohort study by evaluating all children diagnosed with DIPG in the Netherlands between 1990 and 2010.

RESULTS

The incidence of DIPG in the Netherlands corresponds with international literature. Between 1990 and 2010, a large heterogeneity of treatment schedules was applied and only a minority of patients was included in clinical trials.

DISCUSSION

Given the rarity of DIPG, we emphasize the need for (inter-)national trials to facilitate the identification of potentially effective therapeutics in the future. This can be supported by the recent development of a European DIPG registry enabling international study collaborations.

Inadvertent high-dose therapy with temozolomide in a child with recurrent pontine glioma followed by a rapid clinical response but deteriorated after substitution with low-dose therapy

We present a case of inadvertent high-dose therapy with temozolomide in a child with recurrent diffuse intrinsic pontine glioma followed by a rapid clinical response. The patient was a 7-year-old boy who initially presented with a history of left facial palsy, double vision, headache, and ataxia. His symptoms were completely resolved following radiotherapy but recurred 3 months after. Following recurrence, he received temozolomide in a dose >3 times higher than prescribed inadvertently but tolerated well with a rapid clinical response. He eventually deteriorated after he was substituted with a lower dose of temozolomide and died.

Radiation therapy and concurrent topotecan followed by maintenance triple anti-angiogenic therapy with thalidomide, etoposide, and celecoxib for pediatric diffuse intrinsic pontine glioma

BACKGROUND

Despite major treatment attempts, the prognosis for pediatric diffuse intrinsic pontine gliomas (DIPGs) remains dismal. Gliomas are highly vascularized tumors, suggesting that the prevention of vessel formation by anti-angiogenic treatment might be effective.

PROCEDURE

Forty-one pediatric patients with DIPG were treated according to the Angiocomb protocol, starting with radiotherapy combined with topotecan and followed by anti-angiogenic triple medication consisting of thalidomide, etoposide, and celecoxib. Overall survival, radiological response, quality of life, requirement of corticosteroids, and adverse effects were monitored. Eight patients treated with only radiotherapy were used as controls.

RESULTS

For study patients, the 12 and 24 months overall survival was 61% and 17%, respectively. The median overall survival was 12 months (range 4-60 months). Four radiological complete responses were seen, of which two were transient. Radiologically, 56% of the tumors reduced in size and 78% in signal intensity. Study patients were able to visit school or daycare and walk for a significantly longer time compared to controls (Log Rank 0.036 and 0.008, respectively). Adverse effects were generally minor.

CONCLUSIONS

The Angiocomb protocol created a noticeable share of long-term survivors and was well tolerated, suggesting that anti-angiogenic therapy for patients with DIPG should be studied more in the future.

Effect of time from diagnosis to start of radiotherapy on children with diffuse intrinsic pontine glioma

BACKGROUND

Children with diffuse intrinsic pontine glioma (DIPG) continue to have poor outcomes, and radiotherapy (RT) is the only temporarily effective treatment. In this retrospective analysis, we studied the effect of time from diagnosis to start of RT on event-free survival (EFS) and overall survival (OS) in children with DIPG.

METHODS

Records of children (n = 95) with DIPG treated with RT at a single institution between April 1999 and September 2009 were analyzed. RT was delivered at doses of 54.0-55.8 Gy at 1.8 Gy per fraction, and children were followed prospectively. The effect of gender, race, interruption during treatment course, age at diagnosis, duration of symptoms prior to diagnosis, use of protocol-based chemotherapy, and time from diagnosis to initiation of RT on EFS and OS was assessed by the Cox proportional hazards model.

RESULTS

Time as a continuous variable from diagnosis to start of RT did not affect outcome. Time dichotomized to ≤14 days significantly affected OS (hazard ratio [HR] = 1.70, P = 0.014) and race other than white or black affected EFS (HR = 2.32, P = 0.017). The 95 patients had a 6-month EFS and OS of 60 ± 5% and 94.7 ± 2.3%, respectively, and a 12-month EFS and OS of 11.6 ± 3.1% and 49.5 ± 5%, respectively.

CONCLUSIONS

Time as a continuous variable did not affect OS or EFS in our cohort; however, children treated within 2 weeks of diagnosis had poor outcomes. Although rapid initiation of RT is desirable, our findings do not support intensive efforts aimed at shortening delays from diagnosis to start of RT.

Survival prediction model of children with diffuse intrinsic pontine glioma based on clinical and radiological criteria

BACKGROUND

Although diffuse intrinsic pontine glioma (DIPG) carries the worst prognosis of all pediatric brain tumors, studies on prognostic factors in DIPG are sparse. To control for confounding variables in DIPG studies, which generally include relatively small patient numbers, a survival prediction tool is needed.

METHODS

A multicenter retrospective cohort study was performed in the Netherlands, the UK, and Germany with central review of clinical data and MRI scans of children with DIPG. Cox proportional hazards with backward regression was used to select prognostic variables (P < .05) to predict the accumulated 12-month risk of death. These predictors were transformed into a practical risk score. The model's performance was validated by bootstrapping techniques.

RESULTS

A total of 316 patients were included. The median overall survival was 10 months. Multivariate Cox analysis yielded 5 prognostic variables of which the coefficients were included in the risk score. Age ≤3 years, longer symptom duration at diagnosis, and use of oral and intravenous chemotherapy were favorable predictors, while ring enhancement on MRI at diagnosis was an unfavorable predictor. With increasing risk score categories, overall survival decreased significantly. The model can distinguish between patients with very short, average, and increased overall survival (medians of 7.0, 9.7, and 13.7 mo, respectively). The area under the receiver operating characteristic curve was 0.68.

CONCLUSIONS

We developed a DIPG survival prediction tool that can be used to predict the outcome of patients and for stratification in trials. Validation of the model is needed in a prospective cohort.

Antigen-specific immune responses and clinical outcome after vaccination with glioma-associated antigen peptides and polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose in children with newly diagnosed malignant brainstem and nonbrainstem gliomas

PURPOSE

Diffuse brainstem gliomas (BSGs) and other high-grade gliomas (HGGs) of childhood carry a dismal prognosis despite current treatments, and new therapies are needed. Having identified a series of glioma-associated antigens (GAAs) commonly overexpressed in pediatric gliomas, we initiated a pilot study of subcutaneous vaccinations with GAA epitope peptides in HLA-A2-positive children with newly diagnosed BSG and HGG.

PATIENTS AND METHODS

GAAs were EphA2, interleukin-13 receptor alpha 2 (IL-13Rα2), and survivin, and their peptide epitopes were emulsified in Montanide-ISA-51 and given every 3 weeks with intramuscular polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose for eight courses, followed by booster vaccinations every 6 weeks. Primary end points were safety and T-cell responses against vaccine-targeted GAA epitopes. Treatment response was evaluated clinically and by magnetic resonance imaging.

RESULTS

Twenty-six children were enrolled, 14 with newly diagnosed BSG treated with irradiation and 12 with newly diagnosed BSG or HGG treated with irradiation and concurrent chemotherapy. No dose-limiting non-CNS toxicity was encountered. Five children had symptomatic pseudoprogression, which responded to dexamethasone and was associated with prolonged survival. Only two patients had progressive disease during the first two vaccine courses; 19 had stable disease, two had partial responses, one had a minor response, and two had prolonged disease-free status after surgery. Enzyme-linked immunosorbent spot analysis in 21 children showed positive anti-GAA immune responses in 13: to IL-13Rα2 in 10, EphA2 in 11, and survivin in three.

CONCLUSION

GAA peptide vaccination in children with gliomas is generally well tolerated and has preliminary evidence of immunologic and clinical responses. Careful monitoring and management of pseudoprogression is essential.

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.

Molecular profiling of childhood cancer: Biomarkers and novel therapies

BACKGROUND

Technological advances including high-throughput sequencing have identified numerous tumor-specific genetic changes in pediatric and adolescent cancers that can be exploited as targets for novel therapies.

SCOPE OF REVIEW

This review provides a detailed overview of recent advances in the application of target-specific therapies for childhood cancers, either as single agents or in combination with other therapies. The review summarizes preclinical evidence on which clinical trials are based, early phase clinical trial results, and the incorporation of predictive biomarkers into clinical practice, according to cancer type.

MAJOR CONCLUSIONS

There is growing evidence that molecularly targeted therapies can valuably add to the arsenal available for treating childhood cancers, particularly when used in combination with other therapies. Nonetheless the introduction of molecularly targeted agents into practice remains challenging, due to the use of unselected populations in some clinical trials, inadequate methods to evaluate efficacy, and the need for improved preclinical models to both evaluate dosing and safety of combination therapies.

GENERAL SIGNIFICANCE

The increasing recognition of the heterogeneity of molecular causes of cancer favors the continued development of molecularly targeted agents, and their transfer to pediatric and adolescent populations.

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.

Diffuse intrinsic pontine glioma: a reassessment

Diffuse intrinsic pontine glioma (DIPG) is a disease of childhood whose abysmal prognosis has remained unchanged for over 50 years. Biologic investigation has been stymied by lack of pretreatment tissue, as biopsy has been reserved for atypical cases. Recent advances in surgical and molecular-analytic techniques have increased the safety and potential utility of biopsy; brainstem biopsy has now been incorporated into several prospective clinical trials. These and other recent efforts have yielded new insights into DIPG molecular pathogenesis, and opened new avenues for investigation.

Clinical management and outcome of histologically verified adult brainstem gliomas in Switzerland: a retrospective analysis of 21 patients

Because of low incidence, mixed study populations and paucity of clinical and histological data, the management of adult brainstem gliomas (BSGs) remains non-standardized. We here describe characteristics, treatment and outcome of patients with exclusively histologically confirmed adult BSGs. A retrospective chart review of adults (age >18 years) was conducted. BSG was defined as a glial tumor located in the midbrain, pons or medulla. Characteristics, management and outcome were analyzed. Twenty one patients (17 males; median age 41 years) were diagnosed between 2004 and 2012 by biopsy (n = 15), partial (n = 4) or complete resection (n = 2). Diagnoses were glioblastoma (WHO grade IV, n = 6), anaplastic astrocytoma (WHO grade III, n = 7), diffuse astrocytoma (WHO grade II, n = 6) and pilocytic astrocytoma (WHO grade I, n = 2). Diffuse gliomas were mainly located in the pons and frequently showed MRI contrast enhancement. Endophytic growth was common (16 vs. 5). Postoperative therapy in low-grade (WHO grade I/II) and high-grade gliomas (WHO grade III/IV) consisted of radiotherapy alone (three in each group), radiochemotherapy (2 vs. 6), chemotherapy alone (0 vs. 2) or no postoperative therapy (3 vs. 1). Median PFS (24.1 vs. 5.8 months; log-rank, p = 0.009) and mOS (30.5 vs. 11.5 months; log-rank, p = 0.028) was significantly better in WHO grade II than in WHO grade III/IV tumors. Second-line therapy considerably varied. Histologically verification of adult BSGs is feasible and has an impact on postoperative treatment. Low-grade gliomas can simple be followed or treated with radiotherapy alone. Radiochemotherapy with temozolomide can safely be prescribed for high-grade gliomas without additional CNS toxicities.

Hypofractionated conformal radiotherapy for pediatric diffuse intrinsic pontine glioma (DIPG): a randomized controlled trial

BACKGROUND

The pediatric diffuse intrinsic pontine glioma (DIPG) outcome remains dismal despite multiple therapeutic attempts.

PURPOSE

To compare the results of treatment of pediatric diffuse intrinsic pontine glioma (DIPG) using hypofractionated versus conventional radiotherapy.

PATIENTS AND METHODS

Seventy-one newly diagnosed DIPG children were randomized into hypofractionated (HF) (39Gy/13 fractions in 2.6weeks) and conventional (CF) arm (54Gy/30 fractions in 6weeks).

RESULTS

The median and one-year overall survival (OS) was 7.8months and 36.4±8.2% for the hypofractionated arm, and 9.5 and 26.2±7.4% for the conventional arm respectively. The 18-month OS difference was 2.2%. The OS hazard ratio (HR) was 1.14 (95% CI: 0.70-1.89) (p=0.59). The hypofractionated arm had a median and one-year progression-free survival (PFS) of 6.6months and 22.5±7.1%, compared to 7.3 and 17.9±7.1% for the conventional arm. The PFS HR was 1.10 (95% CI: 0.67-1.90) (p=0.71). The 18-month PFS difference was 1.1%. These differences exceed the non-inferiority margin. The immediate and delayed side effects were not different in the 2 arms.

CONCLUSIONS

Hypofractionated radiotherapy offers lesser burden on the patients, their families and the treating departments, with nearly comparable results to conventional fractionation, though not fulfilling the non-inferiority assumption.

Diffuse intrinsic pontine glioma treated with prolonged temozolomide and radiotherapy--results of a United Kingdom phase II trial (CNS 2007 04)

Diffuse intrinsic pontine glioma (DIPG) has a dismal prognosis with no chemotherapy regimen so far resulting in any significant improvement over standard radiotherapy. In this trial, a prolonged regimen (21/28d) of temozolomide was studied with the aim of overcoming O(6)-methylguanine methyltransferase (MGMT) mediated resistance. Forty-three patients with a defined clinico-radiological diagnosis of DIPG received radiotherapy and concomitant temozolomide (75 mg/m(2)) after which up to 12 courses of 21d of adjuvant temozolomide (75-100mg/m(2)) were given 4 weekly. The trial used a 2-stage design and passed interim analysis. At diagnosis median age was 8 years (2-20 years), 81% had cranial nerve abnormalities, 76% ataxia and 57% long tract signs. Median Karnofsky/Lansky score was 80 (10-100). Patients received a median of three courses of adjuvant temozolomide, five received all 12 courses and seven did not start adjuvant treatment. Three patients were withdrawn from study treatment due to haematological toxicity and 10 had a dose reduction. No other significant toxicity related to temozolomide was noted. Overall survival (OS) (95% confidence interval (CI)) was 56% (40%, 69%) at 9 months, 35% (21%, 49%) at 1 year and 17% (7%, 30%) at 2 years. Median survival was 9.5 months (range 7.5-11.4 months). There were five 2-year survivors with a median age of 13.6 years at diagnosis. This trial demonstrated no survival benefit of the addition of dose dense temozolomide, to standard radiotherapy in children with classical DIPG. However, a subgroup of adolescent DIPG patients did have a prolonged survival, which needs further exploration.

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.

Treatment of children with diffuse intrinsic pontine gliomas with chemoradiotherapy followed by a combination of temozolomide, irinotecan, and bevacizumab

BACKGROUND

Diffuse intrinsic pontine gliomas (DIPG) are inoperable and highly resistant tumors to chemotherapy and irradiation. DIPG has the worst prognosis among all pediatric brain tumors and the overwhelming majority of patients die within 6-18 months after diagnosis.

METHODS

We retrospectively reviewed the charts of six DIPG patients treated with chemoradiotherapy (daily carboplatin and oral etoposide in five patients and temozolomide in one patient) followed by maintenance chemotherapy consisting of irinotecan, temozolomide, and bevacizumab at our institution between January 2007 until December 2007.

RESULTS

Event-free survival (EFS) and overall survival (OS) were 10.4 ± 3.08 and 14.6 ± 3.55 months, respectively. Side effects in the patients included hypertension in two, abdominal cramping and diarrhea in four, and neutropenia in five patients.

CONCLUSIONS

This augmented regimen was associated with increased but tolerable toxicity and a modest increase in EFS and OS when compared with published literature in patients with DIPG (median EFS and OS of 6.1 and 9.6 months, respectively). More effective therapies are desperately needed.

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.

A pediatric phase 1 trial of vorinostat and temozolomide in relapsed or refractory primary brain or spinal cord tumors: a Children's Oncology Group phase 1 consortium study

PURPOSE

We conducted a pediatric phase I study to estimate the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), and pharmacokinetic properties of vorinostat, a histone deacetylase (HDAC) inhibitor, when given in combination with temozolomide in children with refractory or recurrent CNS malignancies.

PATIENTS AND METHODS

Vorinostat, followed by temozolomide approximately 1 hour later, was orally administered, once daily, for 5 consecutive days every 28 days at three dose levels using the rolling six design. Studies of histone accumulation in peripheral blood mononuclear cells were performed on Day 1 at 0, 6, and 24 hours after vorinostat dosing. Vorinostat pharmacokinetics (PK) and serum MGMT promoter status were also assessed.

RESULTS

Nineteen eligible patients were enrolled and 18 patients were evaluable for toxicity. There were no DLTs observed at dose level 1 or 2. DLTs occurred in four patients at dose level 3: thrombocytopenia (4), neutropenia (3), and leucopenia (1). Non-dose limiting grade 3 or 4 toxicities related to protocol therapy were also hematologic and included neutropenia, lymphopenia, thrombocytopenia, anemia, and leucopenia. Three patients exhibited stable disease and one patient had a partial response. There was no clear relationship between vorinostat dosage and drug exposure over the dose range studied. Accumulation of acetylated H3 histone in PBMC was observed after administration of vorinostat.

CONCLUSION

Five-day cycles of vorinostat in combination with temozolomide are well tolerated in children with recurrent CNS malignancies with myelosuppression as the DLT. The recommended phase II combination doses are vorinostat, 300 mg/m(2) /day and temozolomide, 150 mg/m(2) /day.

Overcoming the blood-brain barrier in chemotherapy treatment of pediatric brain tumors

Pediatric brain tumors are most common cancers in childhood and among the leading causes of death in children. Chemotherapy has been used as adjuvant (i.e. after) or neoadjuvant (i.e. before) therapy to surgery and radiotherapy for the management of pediatric brain tumors for more than four decades and gained more attention in the recent two decades. Although chemotherapy has demonstrated its effectiveness in the management of some pediatric brain tumors, failure or inactiveness of chemotherapy is commonly met in the clinics and clinical trials. Some of these failures might be attributed to the blood-brain barrier (BBB), limiting the penetration of systemically administered chemotherapeutics into pediatric brain tumors. Therefore, various strategies have been developed and used to address this issue. Herein, we review different methods reported in the literature to circumvent the BBB for enhancing the present of chemotherapeutics in the brain to treat pediatric brain tumors.

Clinico-radiologic characteristics of long-term survivors of diffuse intrinsic pontine glioma

Diffuse intrinsic pontine glioma (DIPG) is the deadliest central nervous system tumor in children. The survival of affected children has remained poor despite treatment with radiation therapy (RT) with or without chemotherapy. We reviewed the medical records of all surviving patients with DIPG treated at our institution between October 1, 1992 and May 31, 2011. Blinded central radiologic review of the magnetic resonance imaging at diagnosis of all surviving patients and 15 controls with DIPG was performed. All surviving patients underwent neurocognitive assessment during follow-up. Five (2.6 %) of 191 patients treated during the study period were surviving at a median of 9.3 years from their diagnosis (range 5.3-13.2 years). Two patients were younger than 3 years, one lacked signs of pontine cranial nerve involvement, and three had longer duration of symptoms at diagnosis. One patient had a radiologically atypical tumor and one had a tumor originating in the medulla. All five patients received RT. Chemotherapy was variable among these patients. Neurocognitive assessments were obtained after a median interval of 7.1 years. Three of four patients who underwent a detailed evaluation showed cognitive function in the borderline or mental retardation range. Two patients experienced disease progression at 8.8 and 13 years after diagnosis. A minority of children with DIPG experienced long-term survival with currently available therapies. These patients remained at high risk for tumor progression even after long follow-ups. Four of our long-term survivors had clinical and radiologic characteristics at diagnosis associated with improved outcome.

Children's Oncology Group's 2013 blueprint for research: central nervous system tumors

In the US, approximately 2,500 children are diagnosed annually with brain tumors. Their survival ranges from >90% to <10%. For children with medulloblastoma, the most common malignant brain tumor, 5-year survival ranges from >80% (standard-risk) to 60% (high-risk). For those with high-grade gliomas (HGGs) including diffuse intrinsic pontine gliomas, 5-year survival remains <10%. Sixty-five percent patients with ependymoma are cured after surgery and radiation therapy depending on the degree of resection and histopathology of the tumor. Phase II trials for brain tumors will investigate agents that act on cMET, PDGFRA, or EZH2 in HGG, DIPG, or medulloblastoma, respectively. Phase III trials will explore risk-based therapy stratification guided by molecular and clinical traits of children with medulloblastoma or ependymoma.

Initial testing (stage 1) of temozolomide by the pediatric preclinical testing program

BACKGROUND

The DNA methylating agent temozolomide was developed primarily for treatment of glioblastoma. However, preclinical data have suggested a broader application for treatment of childhood cancer. Temozolomide was tested against the PPTP solid tumor and ALL models.

PROCEDURES

Temozolomide was tested against the PPTP in vitro panel at concentrations ranging from 0.1 to 1,000 µM and was tested against the PPTP in vivo panels at doses from 22 to 100 mg/kg administered orally daily for 5 days, repeated at day 21.

RESULTS

In vitro temozolomide showed cytotoxicity with a median relative IC50 (rIC50 ) value of 380 µM against the PPTP cell lines (range 1 to > 1,000 µM). The three lines with rIC50 values lesser than 10 µM had low MGMT expression compared to the remaining cell lines. In vivo temozolomide demonstrated significant toxicity at 100 mg/kg, but induced tumor regressions in 15 of 23 evaluable solid tumor models (13 maintained CR [MCR], 2 CR) and 5 of 8 ALL models (3 MCR, 2 CR). There was a steep dose response curve, with lower activity at 66 mg/kg temozolomide and with tumor regressions at 22 and 44 mg/kg restricted to models with low MGMT expression.

CONCLUSIONS

Temozolomide demonstrated high level antitumor activity against both solid tumor and leukemia models, but also elicited significant toxicity at the highest dose level. Lowering the dose of TMZ to more closely match clinical exposures markedly reduced the antitumor activity for many xenograft lines with responsiveness at lower doses closely related to low MGMT expression.

In vitro drug response and efflux transporters associated with drug resistance in pediatric high grade glioma and diffuse intrinsic pontine glioma

Pediatric high-grade gliomas (pHGG), including diffuse intrinsic pontine gliomas (DIPG), are the leading cause of cancer-related death in children. While it is clear that surgery (if possible), and radiotherapy are beneficial for treatment, the role of chemotherapy for these tumors is still unclear. Therefore, we performed an in vitro drug screen on primary glioma cells, including three DIPG cultures, to determine drug sensitivity of these tumours, without the possible confounding effect of insufficient drug delivery. This screen revealed a high in vitro cytotoxicity for melphalan, doxorubicine, mitoxantrone, and BCNU, and for the novel, targeted agents vandetanib and bortezomib in pHGG and DIPG cells. We subsequently determined the expression of the drug efflux transporters P-gp, BCRP1, and MRP1 in glioma cultures and their corresponding tumor tissues. Results indicate the presence of P-gp, MRP1 and BCRP1 in the tumor vasculature, and expression of MRP1 in the glioma cells themselves. Our results show that pediatric glioma and DIPG tumors per se are not resistant to chemotherapy. Treatment failure observed in clinical trials, may rather be contributed to the presence of drug efflux transporters that constitute a first line of drug resistance located at the blood-brain barrier or other resistance mechanism. As such, we suggest that alternative ways of drug delivery may offer new possibilities for the treatment of pediatric high-grade glioma patients, and DIPG in particular.

Phase I trial of capecitabine rapidly disintegrating tablets and concomitant radiation therapy in children with newly diagnosed brainstem gliomas and high-grade gliomas

BACKGROUND

We conducted a phase I study to estimate the maximum tolerated dose and describe the dose-limiting toxicities and pharmacokinetics of oral capecitabine rapidly disintegrating tablets given concurrently with radiation therapy to children with newly diagnosed brainstem or high-grade gliomas.

METHODS

Children 3-21 y with newly diagnosed intrinsic brainstem or high-grade gliomas were eligible for enrollment. The starting dose was 500 mg/m(2), given twice daily, with subsequent cohorts enrolled at 650 mg/m(2) and 850 mg/m(2) using a 3 + 3 phase I design. Children received capecitabine at the assigned dose daily for 9 wks starting from the first day of radiation therapy (RT). Following a 2-wk break, patients received 3 courses of capecitabine 1250 mg/m(2) twice daily for 14 days followed by a 7-day rest. Pharmacokinetic sampling was performed in consenting patients. Six additional patients with intrinsic brainstem gliomas were enrolled at the maximum tolerated dose to further characterize the pharmacokinetic and toxicity profiles.

RESULTS

Twenty-four patients were enrolled. Twenty were fully assessable for toxicity. Dose-limiting toxicities were palmar plantar erythroderma (grades 2 and 3) and elevation of alanine aminotransferase (grades 2 and 3). Systemic exposure to capecitabine and metabolites was similar to or slightly lower than predicted based on adult data.

CONCLUSIONS

Capecitabine with concurrent RT was generally well tolerated. The recommended phase II capecitabine dose when given with concurrent RT is 650 mg/m(2), administered twice daily. A phase II study to evaluate the efficacy of this regimen in children with intrinsic brainstem gliomas is in progress (PBTC-030).

Pediatric diffuse intrinsic pontine glioma patients from a single center

BACKGROUND

The prognosis of children with diffuse intrinsic pontine gliomas (DIPG) is dismal. This study aims to evaluate the characteristics and treatment outcome of children with DIPG in a single center.

METHODS

We reviewed the outcome of children with DIPG treated at the Oncology Institute of Istanbul University from February 1999 to May 2012.

RESULTS

Fifty children (26 female, 24 male) with the median age of 7 years were analyzed. The median duration of symptoms was 30 days. All patients received radiotherapy (RT). Before the year 2000, 12 patients received only RT. Thirty-eight had concomitant and/or adjuvant chemotherapy with RT. Between 2000 and 2004, 17 patients received cis-platinum or vincristine as sensitizers during RT and CCNU + vincristine combination after RT. Since 2004, 21 patients received temozolomide (TMZ) concomitantly during RT and as adjuvant chemotherapy after RT. The median survival time of all patients was 13 months (1-160 months). Patients receiving RT + TMZ had a significantly higher overall survival than patients with only RT (p = 0.018). Patients receiving RT + chemotherapy other than TMZ also had a significantly higher overall survival than patients receiving only RT (p = 0.013). Patients receiving RT + TMZ + and chemotherapy other than TMZ had a significantly higher survival than patients receiving only RT (p = 0.005).

CONCLUSION

In our series, patients receiving RT + TMZ and also patients receiving RT + chemotherapy other than TMZ had a significantly higher overall survival than patients treated with only RT. Hence, administering chemotherapy during and after RT seems to prolong survival in some DIPG patients.

Pharmacotherapeutic management of pediatric gliomas : current and upcoming strategies

Primary glial brain tumors account for the majority of primary brain tumors in children. They are classified as low-grade gliomas (LGG) or high-grade gliomas (HGG), based on specific pathologic characteristics of the tumor, resulting in disparate clinical prognoses. Surgery is a mainstay of treatment for HGG, although it is not curative, and adjuvant therapy is required. Temozolomide, an oral imidazotetrazine prodrug, while considered standard of care for adult HGG, has not shown the same degree of benefit in the treatment of pediatric HGG. There are significant biologic differences that exist between adult and pediatric HGG, and targets specifically aimed at the biology in the pediatric population are required. Novel and specific therapies currently being investigated for pediatric HGG include small molecule inhibitors of epidermal growth factor receptor, platelet-derived growth factor receptor, histone deacetylase, the RAS/AKT pathway, telomerase, integrin, insulin-like growth factor receptor, and γ-secretase. Surgery is also the mainstay for LGG. There are defined front-line, multiagent chemotherapy regimens, but there are few proven second-line chemotherapy options for refractory patients. Approaches such as the inhibition of the mammalian target of rapamycin pathway, inhibition of MEK1 and 2, as well as BRAF, are discussed. Further research is required to understand the biology of pediatric gliomas as well as the use of molecularly targeted agents, especially in patients with surgically unresectable tumors.

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.

Motexafin-gadolinium and involved field radiation therapy for intrinsic pontine glioma of childhood: a children's oncology group phase 2 study

PURPOSE

To evaluate the effects on 1-year event-free survival (EFS) and overall survival (OS) of combining motexafin and gadolinium (MGd), a potent radiosensitizer, with daily fractionated radiation therapy in children with newly diagnosed intrinsic pontine gliomas.

METHODS AND MATERIALS

Patients with newly diagnosed intrinsic pontine glioma were treated with MGd daily for 5 consecutive days each week, for a total of 30 doses. Patients received a 5- to 10-min intravenous bolus of MGd, 4.4 mg/kg/day, given 2 to 5 h prior to standard dose irradiation. Radiation therapy was administered at a daily dose of 1.8 Gy for 30 treatments over 6 weeks. The total dose was 54 Gy.

RESULTS

Sixty eligible children received MGd daily, concurrent with 6 weeks of radiation therapy. The estimated 1-year EFS was 18%±5%, and the estimated 1-year OS was 53%±6.5%. The most common grade 3 to 4 toxicities were lymphopenia, transient elevation of liver transaminases, and hypertension.

CONCLUSIONS

Compared to historical controls, the addition of MGd to a standard 6-week course of radiation did not improve the survival of pediatric patients with newly diagnosed intrinsic pontine gliomas.

Nimotuzumab treatment of malignant gliomas

INTRODUCTION

In spite of new alkylating medication and recently accumulated knowledge about genomics, the prognosis of malignant gliomas remains poor. The introduction of single substances interfering with tumour proliferation dynamics has been disappointing and the lessons learned indicate that a complicated network of proliferation needs time consuming, in-depth analysis in order to more specifically treat now distinguishable subgroups of a disease, which too long was thought of as a uniform entity.

AREAS COVERED

The clinical trials using the EGFR antibody nimotuzumab in the treatment of malignant gliomas are reviewed. Pending conformation in future studies the antibody might be part of the treatment of MGMT-negative, EGFR-amplified, not completely resected gliomas of adulthood and juvenile DIPG (pontine gliomas). Upcoming genomic results of the different tumour entities may suggest certain combination partners of the antibody. Recent studies of nimotuzumab indicate the reason for the lack of toxicity, which is the most attractive argument for its clinical use besides modest efficacy.

EXPERT OPINION

We await the final results on the use of the antibody together with vinorelbine and radiation therapy for the therapy of DIPG. Adult patients with MGMT-negative, EGFR amplified, not totally resected GBM may also profit from this combination therapy. TK-inhibitors combined with the antibody and irradiation may be an option for a therapeutic trial in paediatric patients.

Differences in molecular genetics between pediatric and adult malignant astrocytomas: age matters

The microscope - the classical tool for the investigation of cells and tissues - remains the basis for the classification of tumors throughout the body. Nowhere has this been more true than in the grading of astrocytomas. In spite of the fact that our parents warned us not to judge a book by its cover, we have continued to assume that adult and pediatric malignant gliomas that look the same, will have the same mutations, and thus respond to the same therapy. Rapid advances in molecular biology have permitted us the opportunity to go inside the cell and characterize the genetic events that underlie the true molecular heterogeneity of adult and pediatric brain tumors. In this paper, we will discuss some of the important clinical differences between pediatric and adult gliomas, with a focus on the molecular analysis of these different age groups.

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.

Brain stem gliomas: a clinicopathological study from a single cancer center

Brain stem gliomas (BSG) are rare tumors occurring predominantly in childhood. They are mostly of astrocytic origin and are divided into infiltrative versus circumscribed types, with different prognoses. The diagnosis is mainly based on MRI findings, and biopsy is rarely performed. This is a retrospective study of BSG with available biopsies diagnosed at our center over 6-year period. Fifteen cases were identified, with a predominance of females. The median age was 7 years, and the mean duration of symptoms was <6 weeks in 58.3% (n = 7) of cases. MRI was typical of diffuse pontine gliomas in 64.3% (n = 9) of cases. Radiotherapy was the commonest modality of treatment, and the median overall survival was 21.7 months. Twelve cases were consistent with infiltrative astrocytoma of various grades (2 grade II, 7 grade III and 3 grade IV). Entrapped normal neurons and mitosis were the commonest findings indicating infiltrative growth and high grade, respectively, and those correlated significantly with immunostaining for neurofilament protein and Ki-67 of ≥3%. Overall survival correlated only with the duration of symptoms and tumor grade on biopsies. A limited panel of immunostains might be useful in undetermined cases to decide on the growth pattern and grade.

Pediatric neuro-oncology: current status and future directions

Tumors of the central nervous system (CNS) are the most common solid malignancies in childhood and are the leading cause of cancer-related death in this age group. While an ongoing improvement in overall prognosis has been achieved in the last few decades, current therapeutic approaches still confer significant morbidities, especially for the very young. The traditional strategies of surgery, radiotherapy and conventional cytotoxic chemotherapy need to be further refined while newer approaches, including molecularly targeted agents, hold the promise of better responses, improved outcomes and reduced toxicities. This article discusses treatment standards, the focus of current clinical investigations and the future promise of novel, biologically based approaches for the most common pediatric CNS tumors: primitive neuroectodermal tumors including medulloblastomas, ependymomas and astrocytomas (both low-grade and high-grade glioma).

Temozolomide or bevacizumab for spinal cord high-grade gliomas

High-grade gliomas of the spinal cord are rare tumors, traditionally managed with surgery and radiotherapy. Once patients fail standard treatment, many receive some chemotherapy, although the data supporting such is limited. We reviewed our experience treating high-grade gliomas of the spinal cord with standard intracranial regimens including temozolomide and bevacizumab. Outcomes investigated include radiographic response, clinical response, progression-free survival, and overall survival. We identified eight patients who were treated with temozolomide and six who were treated with bevacizumab. Temozolomide was administered to three patients at initial diagnosis and five patients at recurrence after failing prior radiotherapy. For the recurrent patients, the median time-to-progression was 6.6 months (range 1-40 months) and the median overall survival from initiation of temozolomide was 16.6 months (range 1.2-64.5 months). We identified six patients who received bevacizumab at the time of recurrence. MRI demonstrated a partial response in five patients which also correlated with clinical improvement. The median time to progression was 20.7 months (range 3.3-29.9 months) and median overall survival was 22.8 months (range 3.3-31.8 months). This retrospective review suggests that temozolomide and bevacizumab may be beneficial in spinal cord high-grade gliomas. The compact architecture of the spinal cord makes bevacizumab a particularly appealing agent due to the drug's effect on peritumoral edema and mass effect.

High-grade gliomas in children

High-grade gliomas (HGGs) are malignant tumors and typically include glioblastoma multiforme and anaplastic astrocytoma subtypes. Brainstem gliomas and ependymomas are separate entities with respect to clinical presentation, treatment, prognosis, and outcome in comparison with supratentorial HGGs. In children, these tumors account for 3% to 7% of newly diagnosed brain tumors and 20% of all diagnoses of pediatric supratentorial brain tumors. These neoplasms are highly proliferative and mitotically active and of glial origin. This article reviews clinical, diagnostic, and pathologic features of HGG and current treatments and potential future therapies specific to pediatric patients with HGGs.

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.