Considerations on the Role of Chemotherapy and Modern Radiotherapy in the Treatment of Childhood Low Grade Glioma

Pan-Cancer Study of the Prognosistic Value of Selenium Phosphate Synthase 1

Objective: This study sought to determine the mean prognostic usefulness of seleniumphosphate synthase (SEPHS1) by investigating its expression in 33 human malignancies and its relationship to tumor immunity.Methods: The expression of selenophosphate synthase 1 (SEPHS1) in 33 human malignant tumors was examined using the Genotype-Tissue Expression (GTEx), Cancer Genome Atlas (TCGA), and TIMER databases. Furthermore, the TCGA cohort was used to investigate relationships between SEPHS1 and immunological checkpoint genes (ICGs), tumor mutation burden (TMB), microsatellite instability (MSI), and DNA mismatch repair genes (MMRs). To establish independent risk factors and calculate survival probabilities for liver hepatocellular carcinoma (LIHC) and brain lower-grade glioma (LGG), Cox regression models and Kaplan-Meier curves were utilized. Eventually, the Genomics of Cancer Drug Sensitivity (GDSC) database was used to evaluate the drug sensitivity in LGG and LIHC patients with high SEPHS1 expression.Results: Overall, in numerous tumor tissues, SEPHS1 was highly expressed, and it significantly linked with the prognosis of LGG, ACC, and LIHC (P < .05). Furthermore, in numerous cancers, SEPHS1 expression was linked to tumor-infiltrating immune cells (TIICs), TMB, MSI, and MMRs. According to univariate and multivariate Cox analyses, SEPHS1 expression was significant for patients with LGG and LIHC.Conclusion: High SEPHS1 expression has a better prognosis for LGG, while low SEPHS1 expression has a better prognosis for LIHC. Chemotherapy was advised for LGG patients, particularly for those with high SEPHS1 expression because it can predict how responsive patients will be to 5-Fluorouracil and Temozolomide. This interaction between SEPHS1 and chemoradiotherapy has a positive clinical impact and may be used as evidence for chemotherapy for LGG and LIHC patients.

Pharmacokinetics of oral vinorelbine in French children with recurrent or progressive primary low-grade glioma

AIM

There is a crucial need for pharmacokinetic (PK) data of oral vinorelbine (VNR) in pediatric population. The aim of this work was to assess the PK profile of orally administered VNR in children with recurrent/progressive primary low-grade glioma (LGG).

METHODS

A multicentric, open-label, single-arm intervention phase II study was conducted. Patients, aged between 6 and 18 years, with histologically confirmed recurrent or progressive primary LGG or non-documented typical optic pathway tumors, were included. PK parameters were estimated by non-compartmental analysis using Phoenix WinNonlin® software (version 8.0, Certara, Inc.). The Influence of demographic and biological covariates on VNR PK parameters was investigated using a multivariate linear regression analysis.

RESULTS

PK analysis included 36 patients with a median age (range) of 11 (6-17) years. Estimates of apparent oral clearance (CL/F), apparent volume of distribution (V/F), half-life (t_1/2 ) and their between-subject variability (CV%) at 60 mg.m^-2 dose level, were 472 L.h^-1 (51.8%), 7002 L (57.9%) and 10 h (21.0%), respectively. Negligible accumulation of VNR between C1 and C2 was observed. CL/F and V/F were found to increase with body surface area (BSA) (p = 0.004). Lower area under the concentration-time curve (AUC) levels were observed among children in comparison to adults.

CONCLUSION

Higher doses may be necessary for children with LGG. BSA showed a significant impact on VNR systemic exposure. We believe that our findings will serve as a basis for further studies to better characterize the concentration-response relationships of VNR among pediatric patients.

Long-Term Outcomes of Intra-Arterial Chemotherapy for Progressive or Unresectable Pilocytic Astrocytomas: Case Studies

BACKGROUND

Progressive and/or unresectable pilocytic astrocytomas (PAs) carry a poor prognosis compared to typical PA. Early radiotherapy (RT) may have severe long-term neurocognitive side effects in this patient population. Intra-arterial (IA) chemotherapy is a viable alternative or addition to intravenous (IV) chemotherapy, which may be beneficial in avoidance of early RT.

OBJECTIVE

To evaluate the safety and efficacy of IA chemotherapy in this subset of patients.

METHODS

This is a retrospective review of medical records of PA patients who are treated with IA chemotherapy at Oregon Health & Science University from 1997 until 2019. Response to treatment was categorized as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Progression free survival (PFS) and overall survival (OS) are also reported.

RESULTS

Twelve patients were identified. All patients experienced progression prior to initiation of IA chemotherapy. The most common grade 3 or 4 toxicities related to chemotherapy were thrombocytopenia (66%), neutropenia (66%), leukopenia (50%), anemia (33%), and lymphopenia (16%). Responses achieved were CR in 1, PR in 3, SD in 7, and PD in 1. Median PFS and median OS were 16.5 and 83.5 mo, respectively. A total of 112 procedures (IA injections) were performed and 250 arteries were catheterized. There were 3 minor and no major complications attributable to procedures.

CONCLUSION

This study demonstrates that IA chemotherapy can be safely used in patients with unresectable or progressive PA.

Management of Children with Optic Gliomas and Neurofibromatosis Type 1

Optic pathway gliomas (OPG) are a common cancer in children with neurofibromatosis type 1. OPGs can cause clinical symptoms such as reduction of visual acuity, alterations of the visual field, pallor of the optical papilla, strabismus, endocrinological alterations up to diencephalic syndrome.The current guidelines provide for wait and see as the main approach if the tumor is not causing visual deterioration and adopting treatment only in the event of significant impairment of the visual function. Therefore, it is essential to early detect the visual deterioration changes as well as the identification of children eligible for treatment.

Outcomes Following Proton Therapy for Pediatric Low-Grade Glioma

PURPOSE

Dosimetric studies show that proton therapy can reduce the low/intermediate radiation dose to uninvolved tissue in children with low-grade glioma (LGG). For this reason, LGG is the fourth most common pediatric tumor treated with proton therapy, yet clinical outcome data on efficacy and toxicity are limited.

METHODS AND MATERIALS

We reviewed the medical records of 174 children (≤21 years old) with nonmetastatic LGG enrolled on a prospective protocol and treated with proton therapy between 2007 and 2017. We assessed clinical outcomes and toxicity and analyzed patient, tumor, and treatment-related variables.

RESULTS

The median age was 10.2 years (range, 2-21). Fifty-eight percent of tumors were World Health Organization grade 1 and 30% were grade 2; 12% were diagnosed on imaging characteristics alone. The most common histology was pilocytic astrocytoma (47%). The most common tumor subsites were diencephalon/optic pathway (52%), caudal brainstem (16%), and cerebellum (13%). Forty-two percent received chemotherapy before radiation therapy. The median follow-up was 4.4 years. The 5-year actuarial rates of local control, progression-free survival, and overall survival were 85% (95% confidence interval [CI], 78%-90%), 84% (95% CI, 77%-89%), and 92% (95% CI, 85%-95%), respectively. On univariate analysis, brainstem/spinal cord tumor location (62% vs 90% elsewhere) and dose <54 GyRBE (67% vs 91% for 54 GyRBE) were associated with inferior local control (P < .01 for both). Twenty-two patients (12.6%) experienced acute nausea or vomiting requiring ondansetron; 2 patients (1.1%) required corticosteroids. Serious toxicities (4% of patients) included brainstem necrosis requiring corticosteroids (n = 2), symptomatic vasculopathy (n = 2), radiation retinopathy (n = 1), epilepsy (n = 1), and death from radiation-induced high-grade glioma (n = 1). Thirty-nine patients (22%) developed new-onset central hormone deficiency. Pseudoprogression was observed in 32.1%.

CONCLUSIONS

Compared with modern photon series, proton therapy reduces the radiation dose to developing brain tissue, diminishing acute toxicities without compromising disease control.

Mortality in children with low-grade glioma or glioneuronal tumors: A single-institution study

BACKGROUND

While pediatric low-grade glioma/glioneuronal tumors (LGG/LGGNTs) are considered slow-growing, indolent tumors with excellent long-term prognosis, mortality due to the disease is not unknown. Few studies have addressed the cause of death in this population.

METHODS

Retrospective review of clinicopathologic and radiologic data for children 21 years or younger with LGG/LGGNT who died at St. Jude Children's Research Hospital between April 1985 and June 2015. Our primary objective was to determine the causes and timing of mortality in affected children.

RESULTS

For the 87 eligible patients, median age at diagnosis was 7.7 years (range, 0.21-21 years), median age at death was 14.26 years (range, 0.58-32 years), and median time to death from diagnosis was 4.02 years (range, 0.21-24 years). Midbrain/thalamus was the most common tumor location (n = 34), followed by suprasellar/hypothalamic (n = 18) and cerebrocortical (n = 13). Astrocytoma not otherwise specified (n = 24), pilocytic astrocytoma (n = 23), and fibrillary astrocytoma (n = 11) were the predominant histologic diagnoses. Causes of death included progressive primary disease (PD) (n = 43), progression of PD with histological features of a high-grade glioma at progression or at autopsy (PD-HGG) (n = 15), second cancer (n = 3), suicide (n = 4), and vehicular accident (n = 3). Among the 15 patients with PD-HGG, 12 received radiation therapy before histologic confirmation of progression.

CONCLUSIONS

PD and PD-HGG contributed to 66% of the mortality in our patient cohort. Early psychological intervention should be included as part of the multidisciplinary management approach of children with LGG/LGGNT to reduce the risk of suicide in vulnerable subjects.

Novel drugs in pediatric gliomas

Astrocytomas (gliomas) are the most common primary brain tumors among adults and second most frequent neoplasm among children. New ideas and novel approaches are being explored world over with aim to devise better management strategeies for this deadly pathological state. We searched the electronic database PubMed for pre-clinical as well as clinical controlled trials reporting importance of various therapeutic drugs against gliomas. It was observed clearly that this approach of using therapeutic drugs is clearly evolving and has been observed to be promising future therapeutic avenue against gliomas. The searched literature on whole revealed that although gliomas are treated aggressively with surgery, chemotherapy and radiation, treatment resistance, drug toxicity and poor response rates among pediatric glioma patients, continue to drive the need to discover new and more effective chemotherapeutic agents. The present review is focused on the latest updates in therapeutic drugs against gliomas in pediatric patients. The important chemo-therapeutics discussed in this review included alkylating agents like temoxolomide, derivatives of platinum, nitrosoureas, topoisomerases, angiogenesis inhibitors and cytomegalovirus as therapeutic agents.

Rechallenge to Carboplatin in Children with Low Grade Glioma and Carboplatin Hypersensitivity Reactions

Background: Carboplatin based regimens have demonstrated activity in pediatric patients with low grade gliomas (LGG). However, carboplatin hypersensitivity reactions (CHRs) may be a major problem leading to premature cessation of an effective therapy. The objectives of this study were to describe the prevalence, characteristics and management of CHR.

Methods: We performed a retrospective review of children with LGG treated between January 1994 and July 2015 with carboplatin and vincristine who had a documented CHR. We identified two groups: the first was treated following the schema proposed by Packer et al., and re-exposed to carboplatin using a desensitization protocol; the second was treated according to protocol SIOP LGG 2004 and re-exposed with the infusion time prolonged.

Results: CHRs were observed in 16 patients (34%) out of 47. Hypersensitivity reactions occurred in 6 patients (20.7%) of the first, and 10 patients (55.5%) of the second group, respectively. The grade 2 reactions were the most common. The median number of carboplatin doses administered at the first episode of CHR was 7 (range, 3–9) for the first group, and 8.5 (range, 5–11) for the second, respectively. Six patients were re-exposed to carboplatin using a desensitization protocol; 10 with a prolonged infusion time. Overall success rate for re-exposition was 43.75% (100% and 10%, respectively) (P = 0.001).

Conclusions: Our results show that re-exposure is a safe alternative to abandoning carboplatin. Desensitization showed greater effectiveness compared to a prolonged infusion time, which allowed the patients to receive effective treatment without adverse reactions.

Optic pathway glioma in children: 10 years of experience in a single institution

Optic pathway glioma (OPG) is a rare brain tumor that occurs more commonly during early childhood and is frequently associated with neurofibromatosis type 1 (NF1). In this study, our aim was to describe the characteristics, management, and outcome of patients with OPG. We retrospectively analyzed the clinical charts of all children diagnosed with OPG at our institution from 2003 to 2013. Twenty children (11 boys and 9 girls, median age: 5 and 3/12 years; NF1: 15/20) were diagnosed with OPG. The diagnosis was based on magnetic resonance imaging (MRI) findings. A biopsy was useful in 3 patients. The main reason for seeking medical advice was decreased vision (7/20 patients), whereas in 10/20 patients, the diagnosis was established during the routine follow-up for their NF1. Fifteen patients demonstrated MRI findings of optic nerve involvement and/or chiasmal tumor, whereas in 5 children, postchiasmal structures were also involved. Sixteen patients (16/20) received carboplatin-based regimens, whereas 4/20 patients were only under close observation. Six patients showed deterioration of visual acuity and/or imaging findings at the end of treatment and/or during their follow-up. Three of them (3/6) underwent tumor resection, whereas 1 (1/6) received radiation treatment. None of our patients had total blindness from both eyes. Half of our patients were diagnosed during follow-up for their NF1, the incidence of which was high in our group. Our data suggest that chemotherapy helps in the preservation of vision in the majority of children.

Therapeutic targets in pilocytic astrocytoma based on genetic analysis

Pilocytic astrocytoma (PA) is the most common astrocytic neoplasm of childhood. Patients have an extremely favorable prognosis after surgical resection, qualifying tumors for a grade I designation by the World Health Organization. The molecular data on PA support a key role for the BRAF oncogene in the pathogenesis of these tumors, with the KIAA1549-BRAF fusion being the most common alteration identified in sporadic cases, particularly those occurring in the posterior fossa. Constitutive activation of BRAF leads to downstream activation of the MEK/MAPK/ERK/p16 pathway, which interestingly is also used by cells to activate oncogene-induced senescence (OIS). In fact, the presence of an active OIS pathway might explain the periods of dormancy or spontaneous regression or both, that can be seen in PA. In addition to reviewing the historical evolution, clinicopathologic, predictive, prognostic, and molecular features of PA, we discuss current therapeutic strategies and the caveats that should be considered for the development of therapies that could be used to more effectively treat challenging cases. Individualized treatment requires identification of the type of MAPK alteration, as several alterations in BRAF have been described in addition to the KIAA1549-BRAF fusion. Combination regimens would also appear crucial to achieve tumor eradication and prevent the development of drug resistance. Balancing mitogen-activated protein kinases (MAPK) pathway inhibition with abrogation of an active OIS should be carefully considered as well to preserve any existing protective pathways. Importantly, PAs are largely indolent tumors, and care should be taken to avoid overtreatment, as aggressive therapy could cause more harm than good.

Practical molecular pathologic diagnosis of pilocytic astrocytomas

The pilocytic astrocytoma is predominantly a tumor of childhood and the most common type of circumscribed astrocytoma. The indolent nature of this tumor allows for prolonged survival for most patients, rendering the disease a rather "chronic" one, with potential long-term sequelae that are occasionally related to treatment. Two critical features of this tumor are its tendency to remain dormant, or involute even after subtotal resection, and the exceptional anaplastic transformation, sometimes following adjuvant therapy. The biological behavior of pilocytic astrocytoma can often be related to molecular alterations in the MAPK pathway.

Outcomes of pediatric low-grade gliomas treated with radiation therapy: a single-institution study

Radiation therapy is often considered the treatment of choice for low-grade gliomas. However, given the long-term effects of radiation on the developing brain, the appropriate use of radiation therapy in pediatric patients remains controversial. The purpose of this study was to evaluate progression-free survival (PFS) of pediatric low-grade glioma patients treated with radiation therapy. Data were obtained through a retrospective chart review of patients treated between 1991 and 2008 from a single tertiary care center in the midwest. The study population consisted of 17 patients, of whom 8 (47%) had tumor recurrence after radiation therapy. The median follow-up time was 8.2 years, with a range of 2.3 to 17.2 years. The median age at diagnosis was 5.4 years, and the median age at radiation therapy was 9.4 years. The 3- and the 10-year PFS were 69%± 11.7% and 46%± 13.3%, respectively. A significant difference in PFS was seen when comparing brainstem tumors with hypothalamic/optic pathway tumors (P=0.019). Differences in PFS based on the age at diagnosis, the extent of initial surgery, and indication for radiation therapy were not significant. A larger multicenter study is needed to better assess PFS in these patients.

Concomitant meningioma and glioma within the same optic nerve in neurofibromatosis type 1

A patient with neurofibromatosis type 1 and the rare finding of concomitant meningioma and optic pathway glioma within the same optic nerve is presented. A 4-year-old boy was admitted to our hospital with right-sided proptosis. He also had numerous café-au-lait macules and axillary freckling on physical exam. According to National Institutes of Health (NIH) criteria, he met the diagnostic criteria for neurofibromatosis type 1. On magnetic resonance imaging (MRI), a mass originating from the right optic nerve sheath with normal appearance of the optic nerve was observed, which was consistent with optic nerve sheath meningioma. Another mass lesion was observed in the prechiasmatic region of the same optic nerve, which was consistent with optic nerve glioma. Two different types of optic pathway tumors in the same optic nerve is an extraordinary case. It is important to recognize imaging findings of these tumors and make correct diagnosis.

Efficacy of bevacizumab plus irinotecan in children with recurrent low-grade gliomas--a Pediatric Brain Tumor Consortium study

BACKGROUND

A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in children with recurrent low-grade glioma to measure sustained response and/or stable disease lasting ≥6 months and progression-free survival.

METHODS

Thirty-five evaluable patients received 2 doses (10 mg/kg each) of single-agent BVZ intravenously 2 weeks apart and then BVZ + CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included neuroimaging and expression of tumor angiogenic markers (vascular endothelial growth factor [VEGF], VEGF receptor 2, hypoxia-inducible factor 2α, and carbonic anhydrase 9).

RESULTS

Thirty-five evaluable patients (median age 8.4 y [range, 0.6-17.6]) received a median of 12 courses of BVZ + CPT-11 (range, 2-26). Twenty-nine of 35 patients (83%) received treatment for at least 6 months. Eight patients progressed on treatment at a median time of 5.4 months (range, 1-17.8). Six patients (17.7%) still in follow-up have had stable disease without receiving additional treatment for a median of 40.1 months (range, 30.6-49.3) from initiating therapy. The 6-month and 2-year progression-free survivals were 85.4% (SE ± 5.96%) and 47.8% (SE ± 9.27%), respectively. The commonest toxicities related to BVZ included grades 1-2 hypertension in 24, grades 1-2 fatigue in 23, grades 1-2 epistaxis in 18, and grades 1-4 proteinuria in 15. The median volume of enhancement decreased significantly between baseline and day 15 (P < .0001) and over the duration of treatment (P < .037).

CONCLUSION

The combination of BVZ + CPT-11 appears to produce sustained disease control in some children with recurrent low-grade gliomas.

Expression of bmi-1 in pediatric brain tumors as a new independent prognostic marker of patient survival

Objectives. The B-cell-specific moloney leukemia virus insertion site 1 (the Bmi-1) gene is an important member in the family of polycomb group (PcG) genes that plays an oncogenic role in several types of cancer, but it's expression as a prognostic marker in pediatric brain tumors has not been indicated. Materials and Methods. The Bmi-1 gene expression, clinic pathological and prognostic significance in a series of pediatric brain tumors were examined by real-time PCR method in 56 pediatric brain tumors. Results. The Bmi-1 gene expression in various types of pediatric brain tumors compared to that in normal brain tissue was 4.85-fold. The relative expression varied from 8.64-fold in ependymomas to 2.89-fold in other types. Expression level in high-grade tumors compared to that in low-grade tumors was 2.5 times. In univariate survival analysis of the pediatric brain tumors, a significant association of high expression of the Bmi-1 with patient survival was demonstrated. In multivariate analysis, the Bmi-1 high expression provided significant independent prognostic factors. Conclusion. Increased expression of the Bmi-1 in pediatric brain tumors may be important in the acquisition of an aggressive phenotype. In addition, it can be used as a strong and independent molecular marker of prognosis in pediatric brain tumors.

Pilocytic astrocytoma: a disease with evolving molecular heterogeneity

Pilocytic astrocytoma, the most common pediatric brain tumor, is a clinically and molecularly heterogeneous disease that occurs most often in the cerebellum and hypothalamic and chiasmatic regions. Classically, pilocytic astrocytomas are driven by the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Recently described genetic aberrations involving this pathway are critical for tumorigenesis. Tandem duplication of 7q34 encodes BRAF and produces several KIAA1549-BRAF novel oncogenic fusions. Activating point mutations of BRAF, such as BRAF (V600E), also lead to pilocytic astrocytoma. Loss of the NF1 gene allows hyperactivation of the oncogene KRAS. In this review, we discuss the current understanding of the novel molecular aberrations described in pilocytic astrocytomas and their clinical relevance for prognosis and treatment. The prognostic indications of these aberrations are discussed with regard to tumor location, tumor pathology, and patient age. A better understanding of the evolving molecular heterogeneity of pilocytic astrocytomas offers hope for developing molecularly targeted therapeutic armamentariums.

Prognostic factors and survival patterns in pediatric low-grade gliomas over 4 decades

BACKGROUND

This study reports changes in long-term survival after the introduction of modern imaging in pediatric patients with low-grade gliomas (LGGs).

METHODS

Records from 351 consecutive pediatric patients diagnosed with LGG between 1970 and 2009 at Mayo Clinic Rochester were reviewed and divided into diagnosis before (group I: 1970 to 1989) and after (group II: 1990 to 2009) postoperative magnetic resonance imaging became regularly used in pediatric LGG.

RESULTS

Median progression-free survival (PFS) and overall survival (OS) were not reached. Overall, 10-year PFS was 62% and OS was 90%. On multivariate analysis, improved PFS was associated with gross total resection (GTR; P<0.0001) and postoperative radiation therapy (RT; P<0.0001). In those undergoing less than GTR, PFS was improved with RT, nearing rates of patients receiving GTR (P=0.12). On multivariate analysis, higher OS was associated with GTR (P<0.0001) and pilocytic histology (P=0.03). Group II had fewer headaches, fewer sensory/motor symptoms, less postoperative RT, and more GTRs. OS and PFS were not different between the groups.

CONCLUSIONS

This large series of pediatric LGG patients with long-term follow-up found no significant changes in OS or PFS over time. Overall, GTR was associated with improved OS and PFS. RT was associated with an improvement in PFS, with the greatest benefit seen in patients undergoing less than GTR.

Recurrent pediatric central nervous system low-grade gliomas: the role of surveillance neuroimaging in asymptomatic children

OBJECT

Pediatric low-grade glioma (LGG) is the most common brain tumor of childhood. Except for the known association of gross-total resection and improved survival rates, relatively little is known about the clinical and radiographic predictors of recurrent disease and the optimal frequency of surveillance MRI. The authors sought to determine the clinical and radiographic features associated with recurrent or progressive disease in a single-institutional series of children diagnosed with primary CNS LGG.

METHODS

The authors performed a retrospective analysis of data obtained in 102 consecutive patients diagnosed at Rady Children's Hospital-San Diego between 1994 and 2010 with a biopsy-proven LGG exclusive of a diagnosis of neurofibromatosis. Tumor location, patient age, sex, and symptomatology were correlated with tumor progression or recurrence. Magnetic resonance imaging characteristics and neuroimaging surveillance frequency were analyzed in those children with progressive or recurrent disease.

RESULTS

Forty-six of 102 children diagnosed with an LGG had evidence of recurrent or progressive disease between 2 months and 11 years (mean 27.3 months) after diagnosis. In the larger group of 102 children, gross-total resection was associated with improved progression-free survival (p = 0.012). The location of tumor (p = 0.26), age at diagnosis (p = 0.69), duration of symptoms (p = 0.72), histological subtype (p = 0.74), sex (p = 0.53), or specific chemotherapeutic treatment regimen (p = 0.24) was not associated with tumor progression or recurrence. Sixty-four percent of children with recurrent or progressive disease were asymptomatic, and recurrence was diagnosed by surveillance MRI alone. All children less than 2 years of age in whom the tumor was diagnosed were asymptomatic at the time of progression (p = 0.04). Thirteen percent (6 of 46) of the children had disease recurrence 5 years after initial diagnosis; all of them had undergone an initial subtotal resection. Tumor progression was associated with either homogeneous or patchy T1-weighted post-Gd administration MRI enhancement in 94% of the cases (p = 0.0001).

CONCLUSIONS

Children diagnosed with recurrent LGG may be asymptomatic at the time of recurrence. The authors' findings support the need for routine neuroimaging in a subset of children with LGGs, even when gross-total resection has been achieved, up to 5 years postdiagnosis. The authors found that T1-weighted MR images obtained before and after Gd administration alone may be sufficient to diagnose LGG recurrence and may represent an effective strategy worthy of further validation in a larger multiinstitutional cohort.

Viability screen on pediatric low grade glioma cell lines unveils a novel anti-cancer drug of the steroid biosynthesis inhibitor family

Pediatric low grade gliomas are the most common central nervous system tumors and are still incurable among a subset of patients despite current treatment modalities. Steroid biosynthesis occurs in a wide variety of organs including the brain, to mediate an assortment of functions, including a proposed role in the growth of gliomas. Hence, targeting steroid biosynthesis and/or their signaling pathways, is anticipated as an effective approach for treating gliomas. In this study, we investigated whether our chemical library of steroid inhibitors can modulate the growth of pediatric low grade glioma cell lines (Res186, Res259, R286), and subsequently identified a potent inhibitor of 17β-hydroxysteroid dehydrogenase type 3, referred to as DK16, which functions by attenuating cell viability, proliferation, migration/invasion and anchorage independent growth and conversely induces apoptosis and cell cycle arrest in a dose and duration dependent manner. Further investigations into the mechanisms of how DK16 functions showed that this drug increased the BAX/BCL2 expression ratio, induced phosphatidylserine externalization, and mitochondrial membrane depolarizations culminating to the release and nuclear translocation of AIF. In addition, treatments of low grade glioma cell lines with DK16 increased the expression of pro-apoptotic mediators including CDK2 and CTSL1, and with the converse diminished expression of pro-survival and migratory/invasion genes like PRKCA, TERT, MAPK8, MMP1 and MMP2. Our findings collectively demonstrate the potent anti-neoplastic properties of DK16, a steroid biosynthesis inhibitor, on the growth of pediatric low grade gliomas.

MAPK pathway activation in pilocytic astrocytoma

Pilocytic astrocytoma (PA) is the most common tumor of the pediatric central nervous system (CNS). A body of research over recent years has demonstrated a key role for mitogen-activated protein kinase (MAPK) pathway signaling in the development and behavior of PAs. Several mechanisms lead to activation of this pathway in PA, mostly in a mutually exclusive manner, with constitutive BRAF kinase activation subsequent to gene fusion being the most frequent. The high specificity of this fusion to PA when compared with other CNS tumors has diagnostic utility. In addition, the frequency of alteration of this key pathway provides an opportunity for molecularly targeted therapy in this tumor. Here, we review the current knowledge on mechanisms of MAPK activation in PA and some of the downstream consequences of this activation, which are now starting to be elucidated both in vitro and in vivo, as well as clinical considerations and possible future directions.

Use of a novel sonosensitizer in sonodynamic therapy of U251 glioma cells in vitro

The aim of the present study was to investigate the effect of ZnPcS(2)P(2)-meditated sonodynamic therapy (SDT) on U251 human glioma cells and to identify its underlying biological mechanism. The growth inhibition rate was determined by MTT assay. The apoptotic rate was examined by flow cytometry. Fine structures were observed with transmission electron microscopy (TEM). Generation of reactive oxygen species (ROS) was detected spectrophotometrically. Caspase-3, -8 and -9 expression was detected by Western blot analysis. The growth inhibition rate of U251 human glioma cells indicated that ZnPcS(2)P(2)-meditated SDT had a better growth inhibition rate of tumor cells at a concentration of 5.0 μg/ml ZnPcS(2)P(2), at a 4-h incubation time with ZnPcS(2)P(2), and at 6 h re-incubation following SDT. At 6 h after SDT, the growth inhibition rate of cells was significantly higher compared to other groups, apoptosis could be detected in SDT by flow cytometry. TEM examination revealed morphological features of apoptosis or necrosis. Furthermore, caspase-3, -8 and -9 expression following SDT was found to be increased by Western blot analysis. Finally, generation of ROS in cells was also elevated. In conclusion, ZnPcS(2)P(2)-SDT is capable of inducing U251 cell apoptosis or necrosis and has satisfying antitumor effects. The mechanism of ZnPcS(2)P(2)-meditated SDT involves ROS generation in U251 cells, which initiates subsequent apoptosis through the mitochondrial and death receptor pathways.

Gambogenic acid-induced time- and dose-dependent growth inhibition and apoptosis involving Akt pathway inactivation in U251 glioblastoma cells

Glioblastoma multiforme is the most common and aggressive type of primary brain tumor. Uncontrolled activation of the PI3K/Akt signaling pathway resulting from genetic alterations in phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and epidermal growth factor receptor (EGFR) correlates with poor prognosis and resistance to chemotherapy and radiotherapy of glioblastomas. In this study, we found that gambogenic acid (GNA), a polyprenylated xanthone isolated from the traditional medicine gamboge, efficiently arrested the cell cycle at the G(0)/G(1) phase by specifically repressing the expression of cyclin D1 and cyclin E, suppressed cell proliferation, colony formation and cell migration, and induced caspase-dependent apoptosis in U251 glioblastoma cells in a time- and dose-dependent manner. The pro-apoptotic effect of GNA on U251 cells was shown to be mediated through inactivation of the Akt pathway, because GNA efficiently suppressed the expression level of EGFR and reduced the phosphorylation of Akt (T308) and GSK3β (S9). Furthermore, the combined treatment with LY294002, a specific inhibitor of the PI3K/Akt kinase pathway, and GNA showed a synergistic or additive effect on the growth of U251 cells. Our results showed that GNA is a promising therapeutic agent for glioblastomas.

Feasibility and efficacy of repeated chemotherapy for progressive pediatric low-grade gliomas

BACKGROUND

Chemotherapy is widely accepted as first-line therapy for pediatric low-grade gliomas (LGG). Treatment modalities for further progression are not clearly established. The aim of the study was to determine the feasibility and long-term outcome of repeated chemotherapy for children with recurrent LGG.

METHODS

The study group consisted of patients who received a second line of chemotherapy at progression of their LGG. We compared toxicity, progression-free survival (PFS), and overall survival (OS) of patients treated with chemotherapy at the time of initial diagnosis and patients who received another treatment with chemotherapy at further progression.

RESULTS

Between 1985 and 2009, 118 patients received chemotherapy as primary treatment for LGG, 38 had repeated chemotherapy at further progression. Chemotherapy was tolerated extremely well. Ninety-two percent of patients completed their second line protocol and toxicity was comparable between initial and second line chemotherapy. Five-year OS and PFS were 86 ± 6% and 37 ± 8%, respectively, which were similar to first-line chemotherapy (P = 0.14). Repeated chemotherapy courses were not associated with worsening of visual, neuroendocrine, or other long-term organ sequelae.

CONCLUSION

This study demonstrates high feasibility and low mortality of repeated chemotherapy treatment for progressive LGG. The chronic nature of LGG concerning tumor progression justifies consideration of non-toxic second-line treatment regimens at the time of recurrence. Prospective studies focusing on toxicity and long-term outcome are needed to substantiate this approach.

Impact of chemotherapy on disseminated low-grade glioma in children and adolescents: report from the HIT-LGG 1996 trial

BACKGROUND

We describe demographic data of disseminated childhood low-grade glioma (DLGG) prospectively recruited in the HIT-LGG 1996 study and evaluate the impact of primary chemotherapy (CT) on the outcome of these tumors, which have previously only been described in small and retrospective series.

PATIENTS AND METHODS

The multicenter study HIT-LGG 1996 accrued 1181 children and adolescents with low-grade glioma. 61 patients (5.2%) had tumor dissemination, with 2.8% being present at diagnosis. Frequencies of dissemination for different subgroups were calculated. Efficiency of first-line CT with vincristine/carboplatin was defined in 24 children with dissemination prior to first-line non-surgical-treatment.

RESULTS

Incidence of dissemination was high among infants (16%) with hypothalamic-chiasmatic-glioma (HCG) and diencephalic syndrome. A relevant percentage of HCG showed isolated spinal dissemination. CT achieved objective and overall response rates of 25% and 79% of the primary tumor and a similar response of disseminated lesions. Clinical stabilization or improvement could be achieved in the majority of patients during treatment. However, 20 of 24 patients experienced further progression and 5-year PFS was 6%. Dissemination prior to CT was a negative prognostic factor for PFS within the study (P = 0.005). Overall-survival of primary DLGG was inferior compared to LGG without dissemination at diagnosis (P < 0.001).

CONCLUSION

Complete MRI scan should be a standard diagnostic procedure in young children with hypothalamic-chiasmatic tumors especially if presenting with diencephalic syndrome. Dissemination in childhood LGG relates to impaired PFS. CT delays progression for responders. Multicenter studies have to evaluate the efficacy of extended treatment strategies in DLGG to improve outcome.

Long-term results of brachytherapy with temporary iodine-125 seeds in children with low-grade gliomas

PURPOSE

To retrospectively review the results of temporary I-125 brachytherapy in 94 children and adolescents with low-grade glioma.

METHODS AND MATERIALS

Treatment was performed in progressive tumors roughly spherical in shape with a diameter of up to 5 cm, including 79 astrocytomas, 5 oligodendrogliomas, 4 oligoastrocytomas, 1 ependymoma, and 5 other tumors. Location was suprasellar/chiasmal in 44, thalamic/basal ganglia in 18, hemispheric in 15, midbrain/pineal region in 13, and lower brainstem in 3. Initially, 8% of patients were free of symptoms, 47% were symptomatic but not disabled, and 30% were slightly, 6% moderately, and 3% severely disabled.

RESULTS

5- and 10-year survival was 97% and 92%. The response to I-125 brachytherapy over the long term was estimated after a median observation period of 38.4 (range, 6.4-171.0) months. At that time, 4 patients were in complete, 27 in partial, and 18 in objective remission; 15 showed stable and 30 progressive tumors. Treatment results did not correlate with age, sex, histology, tumor size, location, or demarcation of the tumor. Secondary treatment became necessary in 36 patients, including 19 who underwent repeated I-125 brachytherapy. At final follow-up, the number of symptom-free patients had risen to 21%. Thirty-eight percent showed symptoms without functional impairment, 19% were slightly and 11% moderately disabled, and only 4% were severely disabled.

CONCLUSIONS

Response rates similar to those of conventional radiotherapy or chemotherapy can be anticipated with I-125 brachytherapy in tumors of the appropriate size and shape. We believe it to be a useful contribution to the treatment of low-grade gliomas in children.

Magnolol inhibits human glioblastoma cell proliferation through upregulation of p21/Cip1

Previously, we demonstrated that magnolol isolated from the bark of Magnolia officinalis has anticancer activity in colon, hepatoma, and leukemia cell lines. In this study, we show that magnolol concentration dependently (0-40 microM) decreased the cell number in a cultured human glioblastoma cancer cell line (U373) and arrested the cells at the G0/G1 phase of the cell cycle. Magnolol treatment decreased the protein levels of cyclins A and D1 and increased p21/Cip1, but not cyclins B and D3, cyclin-dependent kinase (CDK)2, CDK4, CDC25C, Weel, p27/Kip1, and p53. The CDK2-p21/Cip1 complex was increased, and the CDK2 kinase activity was decreased in the magnolol-treated U373. Pretreatment of U373 with p21/Cip1 specific antisense oligodeoxynucleotide prevented the magnolol-induced increase of p21/Cip1 protein levels and the decrease of DNA synthesis. Magnolol at a concentration of 100 microM induced DNA fragmentation in U373. Our findings suggest the potential applications of magnolol in the treatment of human brain cancers.

Pediatric brain tumors: current treatment strategies and future therapeutic approaches

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

Relapses of optic pathway tumors after first-line chemotherapy

BACKGROUND

Chemotherapy is accepted as first-line conservative treatment of optic pathway tumors in patients younger than 5. Limited data are available on the outcome of patients with recurrence/progression after initial chemotherapy.

PROCEDURE

Data on 68 children with Optic Pathway Tumors (OPT) treated with first-line Baby Brain (BBSFOP) chemotherapy at the Gustave Roussy Institute in Villejuif between 1990 and 2005 were reviewed.

RESULTS

During a median follow-up of 6 years, 44 (65%) patients were diagnosed with one or more relapses. Most of the relapses occurred during the first 6 years of life. Overall and progression-free survival rates at 5 years after first relapse were 64% and 14%, respectively. First relapse was treated with chemotherapy, radiotherapy or surgery in 28, 9, and 6 patients, respectively. Best response to second-line chemotherapy was partial response in 10, stable disease in 10, and progressive disease in 8 patients. Patients with objective radiologic response to first-line chemotherapy, had a greater chance to respond again to second-line chemotherapy (RR = 90% vs. 15%, P = 0.003). Median time to progression after first relapse was 1.7, 2.5, and 3.1 years after surgery, chemotherapy and radiotherapy, respectively. Finally, 25 (37%) patients received radiotherapy at a median age of 6.7 years.

CONCLUSIONS

Second-line chemotherapy can be effective in the treatment of relapses after first-line chemotherapy and delay further the need for RT, especially in patients whose tumor initially responded to chemotherapy. Despite the desire to avoid irradiation in treatment of young patients with OPT, radiotherapy was used for 37% of patients, usually before the age of 10.

Primary anaplastic pleomorphic xanthoastrocytoma with widespread neuroaxis dissemination at diagnosis--a pediatric case report and review of the literature

We report a 5 year-old boy with primary anaplastic pleomorphic xanthoastrocytoma (PXA) with whole neuroaxis dissemination at diagnosis who experienced the sudden onset of generalized convulsion. Head- and spinal magnetic resonance imaging (MRI) showed widespread gadolinium (Gd)-enhanced lesions extending to the bilateral frontal- and medial temporal lobes and the spinal cord. Subsequent MRI study demonstrated that the lesion size increased without any neurological deterioration. Under a histopathologic diagnosis of anaplastic PXA he underwent adjuvant chemotherapy consisting of 12 cycles of carboplatin and vincristine. The patient is alive without any neurological deficits; follow-up MRI showed that the lesions remained stable during 18 months of chemotherapy. We report a very rare pediatric case of primary anaplastic PXA with dissemination involving the entire neuroaxis at the time of diagnosis.

Pediatric low-grade gliomas and the need for new options for therapy: Why and how?

Pediatric low-grade gliomas are the most common tumors of the central nervous system in children, accounting for almost 50% of all childhood brain tumors. They are a heterogeneous group of tumors with different histologic subtypes. Most treatment studies address low-grade gliomas as a single entity, depriving us of histology-specific treatment outcomes. This is mostly due to a lack of understanding of tumor biology at the molecular level. Pediatric low-grade gliomas are not benign, and most incompletely resected tumors will progress and negatively affect quality of life. The advancements made in understanding sporadic pilocytic astrocytoma and neurofibromatosis 1-associated pilocytic astrocytoma in particular have paved the way for potential targeted therapy and biological stratification. Such progress in pilocytic astrocytoma needs to be consolidated and expanded to other histologic varieties of pediatric low-grade gliomas.

Temozolomide in pediatric low-grade glioma

BACKGROUND

We describe a retrospective series of children with low-grade glioma who received temozolomide.

PROCEDURE

Eligible patients had had a diagnosis of low-grade glioma with or without histological confirmation. Temozolomide was administered at a dose of 200 mg/m(2) daily for 5 days, in a 4-week cycle. Therapy was stopped on completion of the targeted 12 cycles of chemotherapy or on evidence of tumor progression.

RESULTS

Thirteen eligible patients were identified, eight male and five female. Median age at diagnosis was 5.5 years (range 2.6-15.0 years) and at commencement of temozolomide treatment was 9.0 years (range 3.8-15.2 years). Nine patients had a histological diagnosis of pilocytic astrocytoma. Twelve patients had received carboplatin prior to temozolomide, including three in combination with vincristine. A total of 111 cycles of therapy have been administered. Hematological toxicity and nausea were the most common adverse effects. Median time to progression was 6.7 months (range 1.5-41.8 months). Event-free survival rate at 3 years was 57%. Twelve of 13 patients remain alive at the time of report. Eleven have stable disease (SD).

CONCLUSION

Temozolomide appears to be active in pediatric low-grade glioma, with the advantage of oral administration and excellent tolerability.

Temozolomide in children with progressive low-grade glioma

We conducted a phase II study to assess the efficacy of oral temozolomide (TMZ) in children with progressive low-grade glioma. Thirty eligible patients were enrolled on this study. Median age at enrollment was 10 years (range, 4-18 years). Eligible patients received TMZ (200 mg/m(2) per day) by mouth for five days every four weeks. Patients received a median of nine cycles (range, 2-12 cycles) of treatment. Best responses in the 26 patients (86%) with optic pathway glioma (OPG)/pilocytic astrocytoma (PA) included partial response in 3 patients (11%), minor response in 1 (4%), stable disease in 10 (38%), and progressive disease in 12 (46%). Only one of four patients with fibrillary astrocytoma had stable disease for 29 months after TMZ. The overall disease stabilization rate in patients with OPG/PA was 54%, and disease control was maintained for a median interval of 34 months. Seventeen of 26 patients had progressive disease either on or off therapy, and three have died of disease. The two-year progression-free and overall survivals in patients with OPG/PA were 49% (95% CI, 30%-67%) and 96% (95% CI, 89%-100%), respectively. Worst toxicity related to TMZ in all 30 patients included grade 2-4 thrombocytopenia in seven patients, grade 2-4 neutropenia in seven, grade 2 skin rash in one, and intratumor hemorrhage in one. TMZ given in this schedule was successful in stabilizing disease in a significant proportion of the patients with OPG/PA, with manageable toxicity.

Impact of telemedicine on pediatric neuro-oncology in a developing country: the Jordanian-Canadian experience

BACKGROUND

Telemedicine is widely used in industrialized countries for educational purposes. Twinning experiences using telemedicine between institutions in industrialized and developing countries (DC) have been limited. Pediatric neuro-oncology is a complex multidisciplinary discipline that is underserved in most of DC and provides a model to test the feasibility of such tool for twinning purposes.

METHODS

A computer, an EMLO visual presenter HV-7600SX document camera, and a TANDBERG 6000 model videoconference unit were used to present data. For connectivity, we used a six-channel ISDN telephone line. Each channel is 64 megabytes/sec.

RESULTS

Between December 2004 and May 2006, 20 sessions of videoconference were held between King Hussein Cancer Center and the Hospital for Sick Children to discuss 72 cases of 64 patients with various brain tumors (5 patients were discussed twice and 1 patient four times). In 23 patients (36%), major changes from original plan were recommended on different aspects of the care. In 21 patients (91%), those recommendations were followed, with potentially significant positive impact on patients' care.

CONCLUSIONS

Videoconferencing is a feasible and practical twinning tool in pediatric neuro-oncology with a potentially major impact on patient care.