Pediatric high-grade gliomas represent approximately 10% of all pediatric brain tumors. Similar to adult high-grade gliomas, they behave very aggressively, and these children have a very poor ...prognosis despite a variety of therapies that include chemotherapy and radiotherapy. In this review, we present an overview of both pediatric high-grade gliomas and diffuse intrinsic pontine gliomas with a focus on their epidemiology, etiology, presentation, prognostic factors, biology, treatment modalities, outcomes, and future research directions.
High grade gliomas (HGG) are one of the most common central nervous system (CNS) tumors encountered in adults, but they only represent approximately 8-12% of all pediatric CNS tumors. Historically, ...pediatric HGG were thought to be similar to adult HGG since they appear histologically identical; however, molecular, genetic, and biologic data reveal that they are distinct. Similar to adults, pediatric HGG are very aggressive and malignant lesions with few patients achieving long-term survival despite a variety of therapies. Initial treatment strategies typically consist of a gross total resection (GTR) when feasible followed by focal radiotherapy combined with chemotherapy. Over the last few decades, a wealth of data has emerged from basic science and pre-clinical animal models helping to better define the common biologic, genetic, and molecular make-up of these tumors. These data have not only provided a better understanding of tumor biology, but they have also provided new areas of research targeting molecular and genetic pathways with the potential for novel treatment strategies and improved patient outcomes. Here we provide a review of pediatric non-brainstem HGG, including epidemiology, presentation, histology, imaging characteristics, treatments, survival outcomes, and an overview of both basic and translational research. An understanding of all relevant pre-clinical tumor models, including their strengths and pitfalls is essential in realizing improved patient outcomes in this population.
Summary The management of intracranial germ-cell tumours is complex because of varied clinical presentations, tumour sites, treatments and outcomes, and the need for multidisciplinary input. ...Participants of the 2013 Third International CNS Germ Cell Tumour Symposium (Cambridge, UK) agreed to undertake a multidisciplinary Delphi process to identify consensus in the clinical management of intracranial germ-cell tumours. 77 delegates from the symposium were selected as suitable experts in the field and were invited to participate in the Delphi survey, of which 64 (83%) responded to the invitation. Invited participants represented multiple disciplines from Asia, Australasia, Europe, and the Americas. 38 consensus statements encompassing aspects of intracranial germ-cell tumour work-up, staging, treatment, and follow-up were prepared. To achieve consensus, statements required at least 70% agreement from at least 60% of respondents. Overall, 34 (89%) of 38 statements met consensus criteria. This international Delphi approach has defined key areas of consensus that will help guide and streamline clinical management of patients with intracranial germ-cell tumours. Additionally, the Delphi approach identified areas of different understanding and clinical practice internationally in the management of these tumours, areas which should be the focus of future collaborative studies. Such efforts should translate into improved patient outcomes.
Learning Objectives
After completing this course, the reader will be able to:
Discuss the basic epidemiology of pediatric CNS GCTs.
Perform the diagnostic workup and full evaluation that is necessary ...when evaluating a patient with a suspected CNS GCT.
Select among the different therapeutic alternatives employed in treating children with a CNS GCT.
Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Central nervous system (CNS) germ cell tumors (GCTs) represent approximately 3% of primary pediatric brain tumors and encompass a wide pathologic spectrum. CNS GCTs are most commonly located in the pineal and suprasellar regions of the brain and can be divided into major groups including germinomas and nongerminomatous GCTs (NGGCTs), with teratomas often considered a separate category. The clinical presentation varies by location and size, and it frequently includes endocrine abnormalities, visual changes, and signs of increased intracranial pressure. Neuroimaging studies cannot differentiate GCTs from other tumors, and therefore, the diagnosis usually requires histologic confirmation. The rare exceptions are the cases where characteristic elevations of tumor markers, including alpha‐fetoprotein and/or β‐human chorionic gonadotropin are documented in the serum and/or cerebrospinal fluid. In these cases, the imaging findings along with the tumor marker elevation may be diagnostic in themselves without the need for tissue confirmation.
Treatment and prognosis differ greatly between groups. Germinomas have a superior prognosis than NGGCTs. Five‐year overall survival rates >90% were reported initially with the use of craniospinal irradiation. More recently, the use of chemotherapy in addition to radiation therapy has afforded the ability to decrease the dose and volume of radiation therapy without affecting survival rates. NGGCTs are less radiosensitive than germinomas, but the use of adjuvant chemotherapy has improved survival rates in this group as well. The standard management for CNS GCTs remains controversial. Treatment regimens aimed to improve progression‐free and overall survival times are ongoing.
This review focuses on the epidemiology, pathology diagnosis, classification, molecular features, current management, and new therapeutic approaches for central nervous system germ cell tumors.
Abstract
Background
Survivors of pediatric brain tumors are at risk for impaired development in multiple neuropsychological domains. The purpose of this study was to compare neuropsychological ...outcomes of pediatric brain tumor patients who underwent X-ray radiotherapy (XRT) versus proton radiotherapy (PRT).
Methods
Pediatric patients who underwent either XRT or PRT and received posttreatment age-appropriate neuropsychological evaluation—including measures of intelligence (IQ), attention, memory, visuographic skills, academic skills, and parent-reported adaptive functioning—were identified. Multivariate analyses were performed to assess differences in neuropsychological outcomes and included tests for interaction between treatment cohort and follow-up time.
Results
Between 1998 and 2017, 125 patients with tumors located in the supratentorial (17.6%), midline (28.8%), or posterior fossa (53.6%) compartments received radiation and had posttreatment neuropsychological evaluation. Median age at treatment was 7.4 years. The PRT patient cohort had higher estimated SES and shorter median time from radiotherapy completion to last neuropsychological evaluation (6.7 vs 2.6 y, P < 0.001). On multivariable analysis, PRT was associated with higher full-scale IQ (β = 10.6, P = 0.048) and processing speed (β = 14.4, P = 0.007) relative to XRT, with trend toward higher verbal IQ (β = 9.9, P = 0.06) and general adaptive functioning (β = 11.4, P = 0.07). Planned sensitivity analyses truncating follow-up interval in the XRT cohort re-demonstrated higher verbal IQ (P = 0.01) and IQ (P = 0.04) following PRT, with trend toward improved processing speed (P = 0.09).
Conclusions
PRT is associated with favorable outcomes for intelligence and processing speed. Combined with other strategies for treatment de-intensification, PRT may further reduce neuropsychological morbidity of brain tumor treatment.
Primary meningeal melanomatosis is an extremely rare tumor with very few documented responses to treatment. A 3-year-old male with a complex past medical history, including prematurity and shunted ...hydrocephalus, was diagnosed with primary meningeal melanomatosis with peritoneal implants. Molecular testing revealed an NRAS Q61R mutation. The patient received proton craniospinal radiation followed by immunotherapy with nivolumab (1 mg/kg) and ipilimumab (3 mg/kg) IV every 3 weeks and, upon progression, he was switched to a higher dose of nivolumab (3 mg/kg IV every 2 weeks) and binimetinib (24 mg/m
/dose, twice a day). The patient had significant improvement of CNS disease with radiation therapy and initial immunotherapy but progression of extracranial metastatic peritoneal and abdominal disease. Radiation was not administered to the whole abdomen. After two cycles of nivolumab and treatment with the MEK inhibitor binimetinib, he had radiographic and clinical improvement in abdominal metastasis and ascitis. He ultimately died from RSV infection, Klebsiella sepsis, and subdural hemorrhage without evidence of tumor progression. This is the first report of a child with primary meningeal melanomatosis with extracranial metastatic disease with response to a combination of radiation, immunotherapy and MEK inhibitor therapy.
Ependymoma is the third most common brain tumor in children, but there is a paucity of large studies with more than 10 years of follow-up examining the long-term survival and recurrence patterns of ...this disease. We conducted a retrospective chart review of 103 pediatric patients with WHO Grades II/III intracranial ependymoma, who were treated at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center and Chicago’s Ann & Robert H. Lurie Children’s Hospital between 1985 and 2008, and an additional 360 ependymoma patients identified from the Surveillance Epidemiology and End Results (SEER) database. For the institutional cohort, we evaluated clinical and histopathological prognostic factors of overall survival (OS) and progression-free survival (PFS) using the log-rank test, and univariate and multivariate Cox proportional-hazards models. Overall survival rates were compared to those of the SEER cohort. Median follow-up time was 11 years. Ten-year OS and PFS were 50 ± 5% and 29 ± 5%, respectively. Findings were validated in the independent SEER cohort, with 10-year OS rates of 52 ± 3%. GTR and grade II pathology were associated with significantly improved OS. However, GTR was not curative for all children. Ten-year OS for patients treated with a GTR was 61 ± 7% and PFS was 36 ± 6%. Pathological examination confirmed most recurrent tumors to be ependymoma, and 74% occurred at the primary tumor site. Current treatment paradigms are not sufficient to provide long-term cure for children with ependymoma. Our findings highlight the urgent need to develop novel treatment approaches for this devastating disease.
Tumors of the central nervous system (CNS) are a leading cause of morbidity and mortality in the pediatric population. Molecular characterization in the last decade has redefined CNS tumor diagnoses ...and risk stratification; confirmed the unique biology of pediatric tumors as distinct entities from tumors that occur in adulthood; and led to the first novel targeted therapies receiving Food and Drug Administration (FDA) approval for children with CNS tumors. There remain significant challenges to overcome: children with unresectable low‐grade glioma may require multiple prolonged courses of therapy affecting quality of life; children with high‐grade glioma have a dismal long‐term prognosis; children with medulloblastoma may suffer significant short‐ and long‐term morbidity from multimodal cytotoxic therapy, and approaches to improve survival in ependymoma remain elusive. The Children's Oncology Group (COG) is uniquely positioned to conduct the next generation of practice‐changing clinical trials through rapid prospective molecular characterization and therapy evaluation in well‐defined clinical and molecular groups.
Understanding the effect of selumetinib on FASI may help elucidate the biology, proliferative potential, and role in neurocognitive changes for these NF1-associated lesions.
Patients with ...NF1-associated LGG and FASI treated with selumetinib on PBTC-029B were age-matched to untreated patients with NF1-associated FASI at Cincinnati Children's Hospital Medical Center. Paired bidirectional measurements were compared over time using nonparametric tests.
Sixteen age-matched pairs were assessed (age range: 2.8-16.9 years, 60% male). Initial FASI burden was not different between groups (median range 138.7 cm
88.4-182.0 for the treated subjects vs. 121.6 cm
79.6-181.9 for the untreated subjects;
= 0.98). Over a mean follow-up of 18.9 (±5.9) months, the LGG size consistently decreased with treatment while no consistent change among the treated or untreated FASI size was seen. At the paired time points, the median treated LGG decreased significantly more than the treated FASI (-41.3% (LGG) versus -10.7% (FASI),
= 0.006). However, there was no difference in the median size change in the treated versus untreated FASI (-10.7% (treated FASI) versus -17.9% (untreated FASI),
= 0.08). Among the treated subjects, there was no correlation between the change in LGG and FASI (r = -0.04,
= 0.88).
Treatment with selumetinib did not affect the overall FASI size in children with NF1 treated for progressive low-grade glioma.
Survivin is an inhibitor of apoptosis protein that also plays critical roles in regulating the cell cycle and mitosis. Its prominent expression in essentially all human malignancies, and low or ...absent expression in most normal tissues, suggests that it would be an ideal target for cancer-directed therapy. Impeding development of safe and effective survivin antagonists for clinical use is a lack of understanding of the molecular mechanisms by which survivin differentially affects apoptosis and cell division, in normal and malignant cells. We show that the diverse functional roles of survivin can be explained, in part, by its heterodimerization with survivin splice variants in tumor cells. Survivin and survivin-DeltaEx3 interact within the mitochondria where they may inhibit mitochondrial-dependent apoptosis. If the expression of all survivin forms is eliminated by siRNA transfections, cells undergo both apoptosis and defective cell division. Overall, we provide new insights suggesting that targeting specific survivin isoforms, rather than survivin alone, may selectively and effectively destroy tumor cells. These findings are likely to have a significant impact in the design of biologic agents for clinical therapy.
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