Nonrandomized comparison of neurofibromatosis type 1 and non-neurofibromatosis type 1 children who received carboplatin and vincristine for progressive low-grade glioma: A report from the Children's Oncology Group

Targeted therapy for pediatric glioma: RAF(t)ing in the molecular era

BACKGROUND

Pediatric gliomas are the most frequently occurring central nervous system tumors in children. While targeted therapies have been widely applied in the treatment of many adult cancers, their use in pediatric gliomas has lagged behind. However, recent advances in multiomics profiling of pediatric gliomas, coupled with the approval of inhibitors against Raf serine/threonine kinase (RAF), isocitrate dehydrogenase 1/2 (IDH1/2) and neurotrophic receptor tyrosine kinase (NTRK), have spurred significant progress in this field. In light of these developments, this review aims to provide a comprehensive overview of current advancements and the evolving landscape of targeted therapeutic strategies and approaches for pediatric gliomas.

DATA SOURCES

Data analyzed in this study were obtained from the literature from PubMed, as well as other online databases and websites, including ClinicalTrials.gov and the Pediatric Neuro-Oncology Consortium.

RESULTS

Based on findings from multiomics profiling, significant insights have been gained into the genetic and molecular landscape of pediatric gliomas, enabling the identification of key mutations and potentially targetable lesions. These advancements provide rationales for the development of more precise treatment strategies and targeted therapies. Recent approvals of targeted therapies and ongoing clinical trials in pediatric gliomas are converging on the targeting of key signaling molecules and metabolic pathways.

CONCLUSIONS

In the molecular era, targeted therapies offer new hope for more effective and personalized treatment options for pediatric glioma patients. By developing and tailoring treatments to target specific molecular and metabolic vulnerabilities, targeted therapies have the potential to improve the clinical management of pediatric gliomas, ultimately enhancing both the treatment experience and overall prognosis of these patients.

Real-world pharmacokinetics of trametinib in pediatric low-grade glioma

PURPOSE

Trametinib, a MEK1/2 inhibitor, has emerged as a promising treatment for pediatric patients with low-grade gliomas (LGG). However, trametinib exhibits significant inter-individual pharmacokinetic (PK) variability, and studies in adults demonstrated an exposure-efficacy relationship. This study aimed to evaluate the PK profile of trametinib in pediatric routine care and explore potential exposure-outcome relationships.

METHODS

We analyzed PK data from 65 blood samples from 19 children receiving trametinib, either as single agent or in combination with dabrafenib. A trough concentration (Cmin) range of 8-15 ng/mL was considered, based on average exposure reported in the largest pediatric study.

RESULTS

The mean Cmin was 8.82 ng/ml, with 64.6% of samples falling within the predefined target range, while 35.4% were below it. Regarding tolerance, 84.2% of patients experienced treatment-related toxicities, predominantly skin and subcutaneous tissue disorders. Efficacy data were limited.

CONCLUSION

These findings underscore the necessity of therapeutic drug monitoring in pediatric patients to optimize treatment efficacy and minimize toxicity, highlighting trametinib's potential for personalized dosing strategies in this population.

Multimodal deep learning improves recurrence risk prediction in pediatric low-grade gliomas

BACKGROUND

Postoperative recurrence risk for pediatric low-grade gliomas (pLGGs) is challenging to predict by conventional clinical, radiographic, and genomic factors. We investigated if deep learning (DL) of magnetic resonance imaging (MRI) tumor features could improve postoperative pLGG risk stratification.

METHODS

We used a pretrained DL tool designed for pLGG segmentation to extract pLGG imaging features from preoperative T2-weighted MRI from patients who underwent surgery (DL-MRI features). Patients were pooled from 2 institutions: Dana Farber/Boston Children's Hospital (DF/BCH) and the Children's Brain Tumor Network (CBTN). We trained 3 DL logistic hazard models to predict postoperative event-free survival (EFS) probabilities with (1) clinical features, (2) DL-MRI features, and (3) multimodal (clinical and DL-MRI features). We evaluated the models with a time-dependent Concordance Index (Ctd) and risk group stratification with Kaplan-Meier plots and log-rank tests. We developed an automated pipeline integrating pLGG segmentation and EFS prediction with the best model.

RESULTS

Of the 396 patients analyzed (median follow-up: 85 months, range: 1.5-329 months), 214 (54%) underwent gross total resection and 110 (28%) recurred. The multimodal model improved EFS prediction compared to the DL-MRI and clinical models (Ctd: 0.85 (95% CI: 0.81-0.93), 0.79 (95% CI: 0.70-0.88), and 0.72 (95% CI: 0.57-0.77), respectively). The multimodal model improved risk-group stratification (3-year EFS for predicted high-risk: 31% versus low-risk: 92%, P < .0001).

CONCLUSIONS

DL extracts imaging features that can inform postoperative recurrence prediction for pLGG. Multimodal DL improves postoperative risk stratification for pLGG and may guide postoperative decision-making. Larger, multicenter training data may be needed to improve model generalizability.

Low-grade glioma in children with neurofibromatosis type 1: surveillance, treatment indications, management, and future directions

Neurofibromatosis type 1 (NF1) is an autosomal dominant cancer predisposition syndrome characterized by the development of both central and peripheral nervous system tumors. Low-grade glioma (LGG) is the most prevalent central nervous system tumor occurring in children with NF1, arising most frequently within the optic pathway, followed by the brainstem. Historically, treatment of NF1-LGG has been limited to conventional cytotoxic chemotherapy and surgery. Despite treatment with chemotherapy, a subset of children with NF1-LGG fail initial therapy, have a continued decline in function, or recur. The recent development of several preclinical models has allowed for the identification of novel, molecularly targeted therapies. At present, exploration of these novel precision-based therapies is ongoing in the preclinical setting and through larger, collaborative clinical trials. Herein, we review the approach to surveillance and management of NF1-LGG in children and discuss upcoming novel therapies and treatment protocols.

Radiotherapy for pediatric low-grade glioma

INTRODUCTION

Radiotherapy is a highly effective treatment for pediatric low-grade glioma, serving as the standard for evaluating progression-free and overall survival, as well as vision preservation. Despite its proven efficacy, concerns about treatment complications have led to increased use of chemotherapy and targeted therapy, which are associated with poorer progression-free survival outcomes.

METHODS

This review by Indu Bansal and Thomas E. Merchant examines the indications, timing, and results of radiotherapy for pediatric low-grade glioma. The authors provide a comprehensive analysis of clinical management strategies, addressing the controversies surrounding the use and timing of radiotherapy compared to other therapies.

RESULTS

The review highlights that while radiotherapy is essential for certain patients, particularly those who are not candidates for complete resection due to the tumor's infiltrative nature or location, it is often deferred in favor of systemic therapies. This deferral can lead to significant morbidity, including poor visual outcomes. Reports indicate that systemic therapy negatively impacts progression-free survival in patients who eventually undergo radiotherapy. Newer radiotherapy techniques have been developed to minimize complications, offering potential benefits over traditional methods.

DISCUSSION

The evolving clinical management of pediatric low-grade glioma involves balancing the benefits of radiotherapy with concerns about its side effects. Although systemic therapies are increasingly favored, their associated inferior progression-free survival and potential for significant morbidity underscore the need for careful consideration of radiotherapy, particularly in older children, adolescents, or those with progressive disease post-systemic therapy. The emerging role of targeted therapy presents additional challenges, including uncertainties about long-term side effects and its interaction with radiotherapy. Further research is needed to optimize treatment strategies and improve outcomes for pediatric patients with low-grade glioma.

Chemotherapy in pediatric low-grade gliomas (PLGG)

Pediatric low-grade gliomas (PLGG) are commonly treated with a combination of surgery, radiotherapy, and chemotherapy. Recent trends prioritize reducing long-term morbidities, particularly in younger patients. While historically chemotherapy was reserved for cases progressing after radiotherapy, evolving recommendations now advocate for its early use, particularly in younger age groups. The carboplatin and vincristine (CV) combination stands as a standard systemic therapy for PLGG, varying in dosage and administration between North America and Europe. Clinical trials have shown promising response rates, albeit with varying toxicity profiles. Vinblastine has emerged as another effective regimen with minimal toxicity. TPCV, a regimen combining thioguanine, procarbazine, lomustine, and vincristine, was compared to CV in a Children's Oncology Group trial, showing comparable outcomes, but more toxicity. Vinorelbine, temozolomide, and metronomic chemotherapy have also been explored, with varied success rates and toxicity profiles. Around 40-50% of PLGG patients require subsequent chemotherapy lines. Studies have shown varied efficacy in subsequent lines, with NF1 patients generally exhibiting better outcomes. The identification of molecular drivers like BRAF mutations has led to targeted therapies' development, showing promise in specific molecular subgroups. Trials comparing targeted therapy to conventional chemotherapy aim to delineate optimal treatment strategies based on molecular profiles. The landscape of chemotherapy in PLGG is evolving, with a growing focus on molecular subtyping and targeted therapies. Understanding the role of chemotherapy in conjunction with novel treatments is crucial for optimizing outcomes in pediatric patients with low-grade gliomas.

How modern treatments have modified the role of surgery in pediatric low-grade glioma

Low-grade gliomas are the most common brain tumor of childhood, and complete resection offers a high likelihood of cure. However, in many instances, tumors may not be surgically accessible without substantial morbidity, particularly in regard to gliomas arising from the optic or hypothalamic regions, as well as the brainstem. When gross total resection is not feasible, alternative treatment strategies must be considered. While conventional chemotherapy and radiation therapy have long been the backbone of adjuvant therapy for low-grade glioma, emerging techniques and technologies are rapidly changing the landscape of care for patients with this disease. This article seeks to review the current and emerging modalities of treatment for pediatric low-grade glioma.

Dissecting the Natural Patterns of Progression and Senescence in Pediatric Low-Grade Glioma: From Cellular Mechanisms to Clinical Implications

Pediatric low-grade gliomas (PLGGs) comprise a heterogeneous set of low-grade glial and glioneuronal tumors, collectively representing the most frequent CNS tumors of childhood and adolescence. Despite excellent overall survival rates, the chronic nature of the disease bears a high risk of long-term disease- and therapy-related morbidity in affected patients. Recent in-depth molecular profiling and studies of the genetic landscape of PLGGs led to the discovery of the paramount role of frequent upregulation of RAS/MAPK and mTOR signaling in tumorigenesis and progression of these tumors. Beyond, the subsequent unveiling of RAS/MAPK-driven oncogene-induced senescence in these tumors may shape the understanding of the molecular mechanisms determining the versatile progression patterns of PLGGs, potentially providing a promising target for novel therapies. Recent in vitro and in vivo studies moreover indicate a strong dependence of PLGG formation and growth on the tumor microenvironment. In this work, we provide an overview of the current understanding of the multilayered cellular mechanisms and clinical factors determining the natural progression patterns and the characteristic biological behavior of these tumors, aiming to provide a foundation for advanced stratification for the management of these tumors within a multimodal treatment approach.

The management of neurofibromatosis type 1 (NF1) in children and adolescents

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a rare neurogenetic disorder characterized by multiple organ system involvement and a predisposition to benign and malignant tumor development. With revised NF1 clinical criteria and the availability of germline genetic testing, there is now an opportunity to render an early diagnosis, expedite medical surveillance, and initiate treatment in a prompt and targeted manner.

AREAS COVERED

The authors review the spectrum of medical problems associated with NF1, focusing specifically on children and young adults. The age-dependent appearance of NF1-associated features is highlighted, and the currently accepted medical treatments are discussed. Additionally, future directions for optimizing the care of this unique population of children are outlined.

EXPERT OPINION

The appearance of NF1-related medical problems is age dependent, requiring surveillance for those features most likely to occur at any given age during childhood. As such, we advocate a life stage-focused screening approach beginning in infancy and continuing through the transition to adult care. With early detection, it becomes possible to promptly institute therapies and reduce patient morbidity. Importantly, with continued advancement in our understanding of disease pathogenesis, future improvements in the care of children with NF1 might incorporate improved risk assessments and more personalized molecularly targeted treatments.

Temporal changes in treatment and late mortality and morbidity in adult survivors of childhood glioma: a report from the Childhood Cancer Survivor Study

Pediatric glioma therapy has evolved to delay or eliminate radiation for low-grade tumors. This study examined these temporal changes in therapy with long-term outcomes in adult survivors of childhood glioma. Among 2,501 5-year survivors of glioma in the Childhood Cancer Survivor Study diagnosed 1970-1999, exposure to radiation decreased over time. Survivors from more recent eras were at lower risk of late mortality (≥5 years from diagnosis), severe/disabling/life-threatening chronic health conditions (CHCs) and subsequent neoplasms (SNs). Adjusting for treatment exposure (surgery only, chemotherapy, or any cranial radiation) attenuated this risk (for example, CHCs (1990s versus 1970s), relative risk (95% confidence interval), 0.63 (0.49-0.80) without adjustment versus 0.93 (0.72-1.20) with adjustment). Compared to surgery alone, radiation was associated with greater than four times the risk of late mortality, CHCs and SNs. Evolving therapy, particularly avoidance of cranial radiation, has improved late outcomes for childhood glioma survivors without increased risk for late recurrence.

Updates on management of gliomas in the molecular age

Gliomas are primary brain tumors derived from glial cells of the central nervous system, afflicting both adults and children with distinct characteristics and therapeutic challenges. Recent developments have ushered in novel clinical and molecular prognostic factors, reshaping treatment paradigms based on classification and grading, determined by histological attributes and cellular lineage. This review article delves into the diverse treatment modalities tailored to the specific grades and molecular classifications of gliomas that are currently being discussed and used clinically in the year 2023. For adults, the therapeutic triad typically consists of surgical resection, chemotherapy, and radiotherapy. In contrast, pediatric gliomas, due to their diversity, require a more tailored approach. Although complete tumor excision can be curative based on the location and grade of the glioma, certain non-resectable cases demand a chemotherapy approach usually involving, vincristine and carboplatin. Additionally, if surgery or chemotherapy strategies are unsuccessful, Vinblastine can be used. Despite recent advancements in treatment methodologies, there remains a need of exploration in the literature, particularly concerning the efficacy of treatment regimens for isocitrate dehydrogenase type mutant astrocytomas and fine-tuned therapeutic approaches tailored for pediatric cohorts. This review article explores into the therapeutic modalities employed for both adult and pediatric gliomas in the context of their molecular classification.

Therapeutic Strategies for Gliomas Associated With Cancer Predisposition Syndromes

PURPOSE

The purpose of this article was to provide an overview of syndromic gliomas.

DESIGN

The authors conducted a nonsystematic literature review.

RESULTS

Cancer predisposition syndromes (CPSs) are genetic conditions that increase one's risk for certain types of cancer compared with the general population. Syndromes that can predispose one to developing gliomas include neurofibromatosis, Li-Fraumeni syndrome, Lynch syndrome, and tuberous sclerosis complex. The standard treatment for sporadic glioma may involve resection, radiation therapy, and/or alkylating chemotherapy. However, DNA-damaging approaches, such as radiation and alkylating agents, may increase the risk of secondary malignancies and other complications in patients with CPSs. In some cases, depending on genetic aberrations, targeted therapies or immunotherapeutic approaches may be considered. Data on clinical characteristics, therapeutic strategies, and prognosis of syndromic gliomas remain limited.

CONCLUSION

In this review, we provide an overview of syndromic gliomas with a focus on management for patients with CPSs and the role of novel treatments that can be considered.

Pediatric low-grade glioma: State-of-the-art and ongoing challenges

The most common childhood central nervous system (CNS) tumor is pediatric low-grade glioma (pLGG), representing 30%-40% of all CNS tumors in children. Although there is high associated morbidity, tumor-related mortality is relatively rare. pLGG is now conceptualized as a chronic disease, underscoring the importance of functional outcomes and quality-of-life measures. A wealth of data has emerged about these tumors, including a better understanding of their natural history and their molecular drivers, paving the way for the use of targeted inhibitors. While these treatments have heralded tremendous promise, challenges remain about how to best optimize their use, and the long-term toxicities associated with these inhibitors remain unknown. The International Pediatric Low-Grade Glioma Coalition (iPLGGc) is a global group of physicians and scientists with expertise in pLGG focused on addressing key pLGG issues. Here, the iPLGGc provides an overview of the current state-of-the-art in pLGG, including epidemiology, histology, molecular landscape, treatment paradigms, survival outcomes, functional outcomes, imaging response, and ongoing challenges. This paper also serves as an introduction to 3 other pLGG manuscripts on (1) pLGG preclinical models, (2) consensus framework for conducting early-phase clinical trials in pLGG, and (3) pLGG resistance, rebound, and recurrence.

The Neuroimmune Regulation and Potential Therapeutic Strategies of Optic Pathway Glioma

Optic pathway glioma (OPG) is one of the causes of pediatric visual impairment. Unfortunately, there is as yet no cure for such a disease. Understanding the underlying mechanisms and the potential therapeutic strategies may help to delay the progression of OPG and rescue the visual morbidities. Here, we provide an overview of preclinical OPG studies and the regulatory pathways controlling OPG pathophysiology. We next discuss the role of microenvironmental cells (neurons, T cells, and tumor-associated microglia and macrophages) in OPG development. Last, we provide insight into potential therapeutic strategies for treating OPG and promoting axon regeneration.

Children's Oncology Group's 2023 blueprint for research: Central nervous system tumors

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.

Neurofibromatosis Type 1-Associated Optic Pathway Gliomas: Current Challenges and Future Prospects

Optic pathway glioma (OPG) occurs in as many as one-fifth of individuals with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome. Generally considered low-grade and slow growing, many children with NF1-OPGs remain asymptomatic. However, due to their location within the optic pathway, ~20-30% of those harboring NF1-OPGs will experience symptoms, including progressive vision loss, proptosis, diplopia, and precocious puberty. While treatment with conventional chemotherapy is largely effective at attenuating tumor growth, it is not clear whether there is much long-term recovery of visual function. Additionally, because these tumors predominantly affect young children, there are unique challenges to NF1-OPG diagnosis, monitoring, and longitudinal management. Over the past two decades, the employment of authenticated genetically engineered Nf1-OPG mouse models have provided key insights into the function of the NF1 protein, neurofibromin, as well as the molecular and cellular pathways that contribute to optic gliomagenesis. Findings from these studies have resulted in the identification of new molecular targets whose inhibition blocks murine Nf1-OPG growth in preclinical studies. Some of these promising compounds have now entered into early clinical trials. Future research focused on defining the determinants that underlie optic glioma initiation, expansion, and tumor-induced optic nerve injury will pave the way to personalized risk assessment strategies, improved tumor monitoring, and optimized treatment plans for children with NF1-OPG.

Precision based approach to tailoring radiotherapy in the multidisciplinary management of pediatric central nervous system tumors

Modern day survivorship from childhood malignancies is estimated to be over 80%. However, central nervous system tumors remain the leading cause of cancer mortality in children and is the most common solid tumor in this population. Improved survivorship is, in part, a result of improved multidisciplinary care, often with a combination of surgery, radiation therapy, and systemic therapy. With improved survival, long term effects of treatment and quality of life impacts have been recognized and pose a challenge to maximize the therapeutic ratio of treatment. It has been increasingly more apparent that precise risk stratification, such as with the inclusion of molecular classification, is instrumental in efforts to tailor radiotherapy for appropriate treatment, generally towards de-intensification for this vulnerable patient population. In addition, advances in radiotherapy techniques have allowed greater conformality and accuracy of treatment for those who do require radiotherapy for tumor control. Ongoing efforts to tailor radiotherapy, including de-escalation, omission, or intensification of radiotherapy, continue to improve as increasing insight into tumor heterogeneity is recognized, coupled with advances in precision medicine employing novel molecularly-targeted therapeutics.

Loss to follow-up of minorities, adolescents, and young adults on clinical trials: A report from the Children's Oncology Group

BACKGROUND

The increasing number of childhood cancer survivors necessitates continued follow-up to monitor for long-term complications. Inequities in loss to follow-up for patients enrolled on pediatric clinical trials have not been well studied.

METHODS

This was a retrospective study of 21,084 patients residing in the United States enrolled on phase 2/3 and phase 3 Children's Oncology Group (COG) trials between January 1, 2000 and March 31, 2021. Rates of loss to follow-up to COG were evaluated using log-rank tests and multivariable Cox proportional hazards regression models with adjusted hazard ratios (HRs). Demographic characteristics included age at enrollment, race, ethnicity, and zip code level socioeconomic data.

RESULTS

Adolescent and young adult (AYA) patients 15-39 years old at diagnosis had an increased hazard of loss to follow-up compared to patients 0-14 years old (HR, 1.89; 95% confidence interval (CI), 1.76-2.02). In the overall cohort, non-Hispanic Blacks were found to have an increased hazard of loss to follow-up compared to non-Hispanic Whites (HR, 1.56; 95% CI, 1.43-1.70). Among AYAs, the highest loss to follow-up rates were among non-Hispanic Blacks (69.8% ± 3.1%), patients on germ cell tumor trials (78.2% ± 9.2%), and patients living in zip codes with a median household income ≤150% of the federal poverty line at diagnosis (66.7% ± 2.4%).

CONCLUSIONS

AYAs, racial and ethnic minority patients, and those living in lower socioeconomic status areas had the highest rates of loss to follow-up among clinical trial participants. Targeted interventions are warranted to ensure equitable follow-up and improved assessment of long-term outcomes.

PLAIN LANGUAGE SUMMARY

Little is known about disparities in loss to follow-up for pediatric cancer clinical trial participants. In this study, we found that participants who were adolescents and young adults when treated, those who identified as a racial and/or ethnic minority, or those residing in areas with lower socioeconomic status at diagnosis were associated with higher rates of loss to follow-up. As a result, the ability to assess their long-term survival, treatment-related health conditions, and quality of life is hindered. These findings suggest the need for targeted interventions to improve long-term follow-up among disadvantaged pediatric clinical trial participants.

Imaging Guidelines and Recommendations for Diagnosis, Surveillance, and Management of Pediatric CNS and Spinal Tumors

Central nervous system (CNS) tumors are the second most common cause of cancer in children when incidence rates of cancer are estimated according to the Indian population dynamics based on 2011 consensus. As per the estimates, CNS tumors account for 20.1% of cancer burden in children aged between 0 and 14 years and 16.8% when 0 to 19 years age group is considered. The most common pediatric brain tumors are astrocytoma and medulloblastoma followed by other embryonal tumors, craniopharyngioma, and ependymal tumors. The incidence of CNS tumors in children from India is similar to the western high-income countries, other than slightly higher incidence of craniopharyngioma in Indian children.

Pediatric low-grade glioma and neurofibromatosis type 1: A single-institution experience

BACKGROUND

Neurofibromatosis type 1 (NF1)-related gliomas appear to have a clinical behavior different from that of sporadic cases. The purpose of the study was to investigate the role of different factors in influencing the tumor response rate of children receiving chemotherapy for their symptomatic glioma.

METHODS

Between 1995 and 2015, 60 patients with low-grade glioma (42 sporadic cases and 18 cases with NF1) were treated. Patients with brainstem gliomas were excluded. Thirty-nine patients underwent exclusive or postsurgical chemotherapy (vincristine/carboplatin-based regimen).

RESULTS

Disease reduction was achieved in 12 of the 28 patients (42.8%) with sporadic low-grade glioma and in 9 of the 11 patients (81.8%) with NF1, with a significant difference between the 2 groups (P < 0.05). The response to chemotherapy in both the patient groups was not significantly influenced by sex, age, tumor site, and histopathology, although disease reduction occurred more frequently in children aged under 3 years.

CONCLUSIONS

Our study showed that pediatric patients with low-grade glioma and NF1 are more likely to respond to chemotherapy than those with non-NF1.

Pediatric low-grade glioma: Targeted therapeutics and clinical trials in the molecular era

pLGGs are a group of tumors for which the era of molecular diagnostics has truly shifted treatment paradigms and patient care. The discovery that this group of tumors is driven by single-gene alterations/fusions in the MAPK pathway has resulted in relatively rapid translation into targeted therapy options for patients with this often chronic disease. This translation has been facilitated through efforts of multiple collaboratives and consortia and has led to the development of clinical trials testing the role of targeted therapies in pLGG. Although these developments represent promise, many questions remain regarding these therapies including their long-term toxicities and their potential effects on the natural history of pLGG.

Early experience with targeted therapy as a first-line adjuvant treatment for pediatric low-grade glioma

OBJECTIVE

Pediatric low-grade gliomas (pLGGs) frequently exhibit dysregulation of the mitogen-activated protein kinase (MAPK) pathway. Targeted therapies, including mutant BRAF inhibitors (dabrafenib) and MEK inhibitors (trametinib), have shown promise in patients in whom conventional chemotherapy has failed. However, few studies have investigated the use of targeted therapy as a first-line treatment for pLGG. Here, the authors reviewed their institutional experience with using a personalized medicine approach to patients with newly diagnosed pLGGs.

METHODS

All pediatric patients at the authors' institution who had been treated with dabrafenib or trametinib for pLGG without first receiving conventional chemotherapy or radiation were retrospectively reviewed. Demographic, clinical, and radiological data were collected.

RESULTS

Eight patients underwent targeted therapy as a first-line treatment for pLGG. Five patients had a BRAF alteration (1 with a BRAFV600E mutation, 4 with a KIAA1549:BRAF fusion), and 3 patients had an NF1 mutation. One of the 8 patients was initially treated with dabrafenib, and trametinib was added later. Seven patients were initially treated with trametinib; of these, 2 later transitioned to dual therapy, whereas 5 continued with trametinib monotherapy. Six patients (75%) demonstrated a partial response to therapy during their treatment course, whereas stable disease was identified in the remaining 2 patients (25%). One patient experienced mild disease progression after completing a course of trametinib monotherapy, but ultimately stabilized after a period of close observation. Another patient experienced tumor progression while on dabrafenib, but subsequently responded to dual therapy with dabrafenib and trametinib. The most common adverse reactions to targeted therapy were cutaneous toxicity (100%) and diarrhea (50%).

CONCLUSIONS

Targeted therapies have the potential to become a standard treatment option for pLGG due to their favorable toxicity profile and oral route of administration. This case series provides preliminary evidence that targeted therapies can induce an early disease response as a first-line adjuvant treatment; however, large-scale studies are required to assess long-term durability and safety.

Medical Treatment of Pediatric Low-Grade Glioma

Low-grade glioma (LGG) is the most common brain tumor in children and has excellent long-term survival. With an excellent survival rate, the choice of treatment involves careful consideration of minimizing late toxicity from surgery, radiation, and chemotherapy. Surgery, radiation therapy, and chemotherapy can be used as monotherapy or in combination, providing different therapeutic ratios and complications. As a result, establishing the selection of ideal therapies has been a controversial area, presenting challenges. Recent advances in understanding molecular characteristics of pediatric LGG affect classification and treatment approaches. This review aims to overview recent developments in medical treatment in pediatric LGG.

Retrospective and integrative analyses of molecular characteristics and their specific imaging parameters in pediatric grade 1 gliomas

BACKGROUND

Pediatric low-grade gliomas (PLGG) are the most common brain tumors diagnosed during childhood and represent a heterogeneous group associating variable molecular abnormalities. To go further and develop specific statistical patterns between tumor molecular background, imaging features, and patient outcome, a retrospective study was performed in a group of non-neurofibromatosis type 1 (non-NF1) grade 1 PLGGs.

PATIENTS AND METHODS

Seventy-eight children, followed from 2004 to 2017, were retrospectively reported. In this population, we analyzed radiological and molecular parameters. Their therapeutic management comprised surgery or surgery plus chemotherapies.

RESULTS

Considering all 78 patients, 59 had only a surgical removal and 19 patients were treated with postoperative chemotherapy. Twelve progressions were reported in the partially resected and chemotherapeutic groups, whereas four deaths occurred only in the highly treated patients. As expected, in the global cohort, PLGG with BRAF p.V600E and/or CDKN2A loss exhibited poor outcomes and we evidenced significant associations between those molecular characteristics and their imaging presentation. In the chemo-treated patients, when associating initial and 6-month magnetic resonance imaging (MRI) parameters to the molecular features, the good risk situations were significantly linked to the presence of a large tumor cyst at diagnosis and the appearance during treatment of a higher cystic proportion that we called cystic conversion.

CONCLUSION

So, additionally to the presence of BRAF p.V600E or CDKN2A deletion in grade 1 PLGGs, the absence on diagnostic MRI of cystic parts and/or cystic conversion at 6-month chemotherapy were significantly linked to a worst prognosis and response to treatment. These imaging features should be considered as prognostic markers in future PLGG studies.

EANO - EURACAN - SNO Guidelines on circumscribed astrocytic gliomas, glioneuronal, and neuronal tumors

In the new WHO 2021 Classification of CNS Tumors the chapter "Circumscribed astrocytic gliomas, glioneuronal and neuronal tumors" encompasses several different rare tumor entities, which occur more frequently in children, adolescents, and young adults. The Task Force has reviewed the evidence of diagnostic and therapeutic interventions, which is low particularly for adult patients, and draw recommendations accordingly. Tumor diagnosis, based on WHO 2021, is primarily performed using conventional histological techniques; however, a molecular workup is important for differential diagnosis, in particular, DNA methylation profiling for the definitive classification of histologically unresolved cases. Molecular factors are increasing of prognostic and predictive importance. MRI finding are non-specific, but for some tumors are characteristic and suggestive. Gross total resection, when feasible, is the most important treatment in terms of prolonging survival and achieving long-term seizure control. Conformal radiotherapy should be considered in grade 3 and incompletely resected grade 2 tumors. In recurrent tumors reoperation and radiotherapy, including stereotactic radiotherapy, can be useful. Targeted therapies may be used in selected patients: BRAF and MEK inhibitors in pilocytic astrocytomas, pleomorphic xanthoastrocytomas, and gangliogliomas when BRAF altered, and mTOR inhibitor everolimus in subependymal giant cells astrocytomas. Sequencing to identify molecular targets is advocated for diagnostic clarification and to direct potential targeted therapies.

The role of irinotecan-bevacizumab as rescue regimen in children with low-grade gliomas: a retrospective nationwide study in 72 patients

INTRODUCTION

At least half of children with low-grade glioma (LGG) treated with first line chemotherapy experience a relapse/progression and may therefore need a second-line chemotherapy. Irinotecan-bevacizumab has been recommended in this setting in France after encouraging results of pilot studies. We performed a retrospective analysis to define the efficacy, toxicity and predictors for response to the combination on a larger cohort.

METHODS

We reviewed the files from children < 19 years of age with progressive or refractory LGG treated between 2009 and 2016 in 7 French centers with this combination.

RESULTS

72 patients (median age 7.8 years [range 1-19]) received a median of 16 courses (range 3-30). The median duration of treatment was 9 months (range 1.4-16.2). 96% of patients experienced at least disease stabilization. The 6-month and 2-year progression-free survivals (PFS) were 91.7% [IC 95% 85.5-98.3] and 38.2% [IC 95% 28.2-51.8] respectively. No progression occurred after treatment in 18 patients with a median follow-up of 35.6 months (range 7.6-75.9 months). Younger patients had a worse PFS (p = 0.005). Prior chemoresistance, NF1 status, duration of treatment, histopathology or radiologic response did not predict response. The most frequent toxicities related to bevacizumab included grades 1-2 proteinuria in 21, epistaxis in 10, fatigue in 12 and hypertension in 8 while gastro-intestinal toxicity was the most frequent side effect related to irinotecan.

CONCLUSIONS

Bevacizumab-irinotecan has the potential of disease control clinically and radiographically in children with recurrent LGG whatever their previous characteristics; in many cases however these responses are not sustained, especially in younger children.

Visual Outcomes of Optic Pathway Glioma Treated With Chemotherapy in Neurofibromatosis Type 1

PURPOSE

To analyze the visual outcomes following chemotherapy for optic pathway glioma in children with neurofibromatosis type 1.

METHODS

This was a retrospective cohort study of 58 children with optic pathway glioma between 2003 and 2019. Best corrected visual acuity (BCVA) at diagnosis and at the last follow-up visit were analyzed. Correlation tests were performed to determine whether the final BCVA was predicted by the initial BCVA, initial Dodge stage, or retinal nerve fiber layer (RNFL) thickness stability. The first-line chemotherapy regimen included vincristine plus carboplatin (2003 to 2016) and vinblastine (since 2017).

RESULTS

Twenty-four children (41%) received chemotherapy. The median age at diagnosis was 3 years, and 61% of the children were female. From the first visit to the last follow-up visit, there was a statistically significant difference in mean BCVA in eyes in the no treatment group (P = .034) but not in eyes in the chemotherapy group (P = .824). A moderate and weak positive correlation was found (r = 0.58 and r = 0.29, respectively). At the last follow-up visit, BCVA remained stable in 73% and improved in 27% of eyes in the no treatment group, and BCVA worsened in 25%, remained stable in 62%, and improved in 13% of eyes in the chemotherapy group. At the last follow-up visit, BCVA and Dodge stage had a weak negative correlation (r = -0.06 and r = -0.17, respectively). A negative moderate correlation was identified between RNFL thickness and BCVA at the last follow-up visit (r = -0.48 in the no treatment group and r = -0.46 in the chemotherapy group).

CONCLUSIONS

Children treated with chemotherapy had worse BCVA, although the treatment arrested the decline or improved BCVA in 75% of the patients with no major side effects. [J Pediatr Ophthalmol Strabismus. 2022;59(2):128-135.].

Glioma targeted therapy: insight into future of molecular approaches

Gliomas are the common type of brain tumors originating from glial cells. Epidemiologically, gliomas occur among all ages, more often seen in adults, which males are more susceptible than females. According to the fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5), standard of care and prognosis of gliomas can be dramatically different. Generally, circumscribed gliomas are usually benign and recommended to early complete resection, with chemotherapy if necessary. Diffuse gliomas and other high-grade gliomas according to their molecule subtype are slightly intractable, with necessity of chemotherapy. However, for glioblastoma, feasible resection followed by radiotherapy plus temozolomide chemotherapy define the current standard of care. Here, we discuss novel feasible or potential targets for treatment of gliomas, especially IDH-wild type glioblastoma. Classic targets such as the p53 and retinoblastoma (RB) pathway and epidermal growth factor receptor (EGFR) gene alteration have met failure due to complex regulatory network. There is ever-increasing interest in immunotherapy (immune checkpoint molecule, tumor associated macrophage, dendritic cell vaccine, CAR-T), tumor microenvironment, and combination of several efficacious methods. With many targeted therapy options emerging, biomarkers guiding the prescription of a particular targeted therapy are also attractive. More pre-clinical and clinical trials are urgently needed to explore and evaluate the feasibility of targeted therapy with the corresponding biomarkers for effective personalized treatment options.

Risk factors for treatment-refractory and relapsed optic pathway glioma in children with neurofibromatosis type 1

BACKGROUND

Nearly one-third of patients with neurofibromatosis type 1-associated optic pathway glioma (NF1-OPG) fail frontline chemotherapy; however, little is known about risk factors for treatment failure.

METHODS

We performed a retrospective multi-institutional cohort study to identify baseline risk factors for treatment-refractory/relapsed disease and poor visual outcome in children with NF1-OPG. Refractory/relapsed NF1-OPG was defined as a requirement of two or more treatment regimens due to progression or relapse.

RESULTS

Of 111 subjects eligible for inclusion, adequate clinical and visual data were available for 103 subjects from 7 institutions. Median follow-up from the initiation of first chemotherapy regimen was 95 months (range 13-185). Eighty-four (82%) subjects received carboplatin-based frontline chemotherapy. Forty-five subjects (44%) experienced refractory/relapsed disease, with a median time of 21.5 months (range 2-149) from the initiation of first treatment to the start of second treatment. The proportion of patients without refractory/relapsed disease at 2 and 5 years was 78% and 60%. In multivariable analyses, age less than 24 months at initial treatment, posterior tumor location, and familial inheritance were associated with refractory/relapsed NF1-OPG by 2 years. Both age less than 24 months and posterior tumor location were associated with refractory/relapsed NF1-OPG by 5 years. Subjects with moderate to severe vision loss at last follow-up were more likely to have posterior tumor location, optic disc abnormalities, or abnormal visual acuity at initial treatment.

CONCLUSION

Young age, posterior tumor location, and optic disc abnormalities may identify patients with the greatest likelihood of refractory/relapsed NF1-OPG and poor visual outcomes, and who may benefit from newer treatment strategies.

Pediatric and Adult Low-Grade Gliomas: Where Do the Differences Lie?

Two thirds of pediatric gliomas are classified as low-grade (LGG), while in adults only around 20% of gliomas are low-grade. However, these tumors do not only differ in their incidence but also in their location, behavior and, subsequently, treatment. Pediatric LGG constitute 65% of pilocytic astrocytomas, while in adults the most commonly found histology is diffuse low-grade glioma (WHO II), which mostly occurs in eloquent regions of the brain, while its pediatric counterpart is frequently found in the infratentorial compartment. The different tumor locations require different skillsets from neurosurgeons. In adult LGG, a common practice is awake surgery, which is rarely performed on children. On the other hand, pediatric neurosurgeons are more commonly confronted with infratentorial tumors causing hydrocephalus, which more often require endoscopic or shunt procedures to restore the cerebrospinal fluid flow. In adult and pediatric LGG surgery, gross total excision is the primary treatment strategy. Only tumor recurrences or progression warrant adjuvant therapy with either chemo- or radiotherapy. In pediatric LGG, MEK inhibitors have shown promising initial results in treating recurrent LGG and several ongoing trials are investigating their role and safety. Moreover, predisposition syndromes, such as neurofibromatosis or tuberous sclerosis complex, can increase the risk of developing LGG in children, while in adults, usually no tumor growth in these syndromes is observed. In this review, we discuss and compare the differences between pediatric and adult LGG, emphasizing that pediatric LGG should not be approached and managed in the same way as adult LCG.

Brain Cancers in Genetic Syndromes

PURPOSE OF REVIEW

Although genetic conditions that cause primary central nervous system tumors are rare, their pathophysiology influences both treatment and surveillance. This article reviews the most frequently occurring genetic conditions associated with brain cancers and highlights the most recent therapeutic approaches in the treatment of Lynch syndrome (and other disorders of the mismatch repair system), neurofibromatosis 1, and Li-Fraumeni syndrome.

RECENT FINDINGS

Recent advances in molecular diagnostics have considerably improved the ability to diagnose genetic conditions in people with primary brain tumors. The common application of next-generation sequencing analyses of tissue increases the frequency with which clinicians are forced to address the possibility of an underlying genetic condition based on tissue molecular findings. Clinicians must be aware of the clinical presentation of genetic conditions predisposing to brain tumors in order to discern which patients are appropriate for germline genetic testing. Advances in therapeutics for specific genetic variants are increasingly available, and accurately diagnosing an underlying genetic condition may directly impact patient outcomes.

Disseminated craniospinal low-grade glioma in a patient with NF-1 without optic pathway pathology: illustrative case

BACKGROUND

Neurofibromatosis type 1 (NF-1) is a neurocutaneous autosomal dominant disorder that predisposes patients to develop intracranial low-grade gliomas (LGGs). Most LGGs in patients with NF-1 involve the optic pathway but can arise anywhere throughout the central nervous system. NF-1–related disseminated pediatric LGG (dPLGG) in the absence of a dominant optic pathway glioma has not been described.

OBSERVATIONS

The authors discussed a case of a 10-year-old boy who presented with consideration for biopsy with nonoptic pathway PLGG with craniospinal dPLGG in the setting of NF-1. The patient’s primary lesion, located in the right medulla, was initially treated with surveillance before induction chemotherapy with carboplatin and vincristine was initiated. However, surveillance imaging demonstrated significant increase in size and enhancement, and subsequent craniospinal imaging demonstrated extensive nodular dissemination in the cervicothoracic spine. A biopsy and molecular testing were subsequently performed to further evaluate the tumor, and the patient was diagnosed with dPLGG with CDKN2A deletion.

LESSONS

Thorough craniospinal magnetic resonance imaging evaluation and biopsy in nonoptic pathway–dominant brain lesions in NF-1 are warranted in patients with atypical clinical and radiological findings in whom standard chemotherapeutic therapy fails.

Multiple Intraspinal Gangliogliomas in a Child With Neurofibromatosis Type 1: Case Report and Literature Review

Neurofibromatosis type 1 (NF1)-associated primary intramedullary spinal cord ganglioglioma has only rarely been reported. Because of frequent nonresectability, they pose significant management challenges despite clinical indolence. This report describes a 4-year-old girl with NF1 who was found to have multiple discrete, infiltrative intramedullary cord masses, and biopsy demonstrated World Health Organization grade I ganglioglioma. Panel-based next-generation sequencing showed her previously identified germline NF1 mutation and a second somatic NF1 mutation. This represents the first report of multiple primary intramedullary gangliogliomas in a child with NF1 and demonstrates how biopsy with panel-based next-generation sequencing provides potential targets for MAPK/MEK/BRAF pathway inhibitor therapy.

Lessons learned from drug trials in neurofibromatosis: A systematic review

Neurofibromatosis (NF) is the umbrella term for neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and schwannomatosis (SWN). EU-PEARL aims to create a framework for platform trials in NF. The aim of this systematic review is to create an overview of recent clinical drug trials in NF, to identify learning points to guide development of the framework. We searched Embase, Medline and Cochrane register of trials on October 1, 2020 for publications of clinical drug trials in NF patients. We excluded publications published before 2010, systematic reviews, secondary analyses and studies with <10 patients. Data was extracted on manifestations studied, study design, phase, number of participating centres and population size. Full-text review resulted in 42 articles: 31 for NF1, 11 for NF2, none for SWN. Most NF1 trials focused on plexiform neurofibromas (32%). Trials in NF2 solely studied vestibular schwannomas. In NF1, single-arm trials (58%) were most common, and the majority was phase II (74%). For NF2 most trials were single-arm (55%) and exclusively phase II. For both diseases, trials were predominantly single-country and included five centres or less. Study population sizes were small, with the majority including ≤50 patients (74%). In conclusion, NF research is dominated by studies on a limited number out of the wide range of manifestations. We need more trials for cutaneous manifestations and high-grade gliomas in NF1, manifestations other than vestibular schwannoma in NF2 and trials for SWN. Drug development in NF may profit from innovative trials on multiple interventions and increased international collaboration.

Upfront treatment with mTOR inhibitor everolimus in pediatric low-grade gliomas: A single-center experience

Pediatric low-grade gliomas (pLGGs) are the most frequent brain tumor in children. Adjuvant treatment, consisting in chemotherapy and radiotherapy, is often necessary if a complete surgical resection cannot be obtained. Traditional treatment approaches result in a significant long-term morbidity, with a detrimental impact on quality of life. Dysregulation of the mitogen-activated protein kinase (MAPK) pathway is the molecular hallmark of pLGGs and hyperactivation of the downstream mammalian target of rapamycin (mTOR) pathway is frequently observed. We report clinical and radiological results of front-line treatment with everolimus in 10 consecutive patients diagnosed with m-TOR positive pLGGs at the Bambino Gesù Children's Hospital in Rome, Italy. Median duration of treatment was 19 months (range from 13-60). Brain magnetic resonance imaging showed stable disease in 7 patients, partial response in 1 and disease progression in 2. Therapy-related adverse events were always reversible after dose reduction or temporary treatment interruption. To the best of our knowledge, this is the first report of everolimus treatment for chemo- and radiotherapy-naïve children with pLGG. Our results provide preliminary support, despite low sample size, for the use of everolimus as target therapy in pLGG showing lack of progression with a manageable toxicity profile.

Doubling Recruitment of Pediatric Low-grade Glioma within Two Decades does not change Outcome - Report from the German LGG Studies

BACKGROUND

Successive multicenter studies for pediatric low-grade glioma (LGG) in Germany were accompanied by a doubling of annual recruitment over 2 decades. We investigated whether this increase conveyed a change of epidemiologic characteristics or survival.

METHODS AND RESULTS

Participating centers reported 4634 patients with the radiologic/histologic diagnosis of LGG (1996-2018), rising from 109 to 278/year. Relating these numbers to all pediatric CNS tumors registered at the German Childhood Cancer Registry, the LGG fraction and annual crude incidence rates increased (32% to 51%; 0.94 to 2.12/100,000 children/adolescents<15 years). The consecutive LGG studies recruited 899 (HIT-LGG 1996), 1592 (SIOP-LGG 2004), and 1836 (LGG-registry) patients with similar distribution of tumor-sites, histology, and dissemination. 5-year overall survival was 96%-98% at median observation time of 8.1 years. Acknowledging unequal follow-up periods, 589/899 (66%), 1089/1582 (69%), and 1387/1836 (76%) patients remained under observation, while 1252/4317 received adjuvant treatment with decreasing frequency of front-line radiotherapy from 16% to 5%.

CONCLUSION

Pediatric LGG incidence rates in Germany are now comparable to other European countries. The rise in patient numbers followed implementation of standard-of-care treatment protocols, but did not result in relevant changes of epidemiologic or clinical parameters or survival. Shifts in patient distribution between treatment arms reflect growing acceptance of the LGG therapy algorithm.

HINTERGRUND

In den vergangenen 20 Jahren hat sich die jährliche Patientenrekrutierung in den aufeinanderfolgenden multizentrischen Studien für pädiatrische niedrig-gradige Gliome (LGG) in Deutschland verdoppelt. Wir haben untersucht, ob sich mit dieser Zunahme auch epidemiologische Merkmale oder das Überleben verändert haben.

METHODIK UND ERGEBNISSE

Zwischen 1996 und 2018 meldeten die teilnehmenden Zentren insgesamt 4634 Patienten mit der radiologischen/histologischen Diagnose eines LGG. Die Zahl stieg von anfangs 109 bis 278 Patienten pro Jahr. Gleichzeitig stieg der Anteil der LGGs an allen am Deutschen Kinderkrebsregister gemeldeten pädiatrischen Hirntumoren von 32 auf 51%, die jährliche Inzidenz erhöhte sich von 0,94 auf 2,12/100 000 Kinder/Jugendliche<15 Jahre. Die aufeinanderfolgenden LGG-Studien rekrutierten 899 (HIT-LGG 1996), 1592 (SIOP-LGG 2004) und 1836 (LGG-Register) Patienten mit vergleichbarer Verteilung von Tumorsitz, Histologie und Disseminierung. Das 5-Jahres-Überleben lag bei einer medianen Nachbeobachtungszeit von 8,1 Jahren zwischen 96 und 98%. Unter Berücksichtigung der ungleich langen Follow-up-Zeit wurden 589/899 (65,5%), 1089/1582 (68,8%) und 1387/1836 (75,5%) Patienten bislang beobachtet, während 1252/4317 eine adjuvante Therapie erhielten. Dabei sank der Anteil der primären Radiotherapie von 16 auf 5%.

SCHLUSSFOLGERUNG

Die Rekrutierung pädiatrischer LGG ist dank Implementierung verbindlicher Therapiestandards in Deutschland gestiegen, ohne zu relevanten Veränderungen epidemiologischer oder klinischer Merkmale oder des Überlebens zu führen. Die Inzidenz ist mit anderen europäischen Ländern vergleichbar. Verschiebungen der Patientenzuteilung zwischen den Therapiearmen spiegeln die zunehmende Akzeptanz des LGG-Therapie-Algorithmus wider.

NF1 optic pathway glioma: analyzing risk factors for visual outcome and indications to treat

BACKGROUND

The aim of the project was to identify risk factors associated with visual progression and treatment indications in pediatric patients with neurofibromatosis type 1 associated optic pathway glioma (NF1-OPG).

METHODS

A multidisciplinary expert group consisting of ophthalmologists, pediatric neuro-oncologists, neurofibromatosis specialists, and neuro-radiologists involved in therapy trials assembled a cohort of children with NF1-OPG from 6 European countries with complete clinical, imaging, and visual outcome datasets. Using methods developed during a consensus workshop, visual and imaging data were reviewed by the expert team and analyzed to identify associations between factors at diagnosis with visual and imaging outcomes.

RESULTS

Eighty-three patients (37 males, 46 females, mean age 5.1 ± 2.6 y; 1-13.1 y) registered in the European treatment trial SIOP LGG-2004 (recruited 2004-2012) were included. They were either observed or treated (at diagnosis/after follow-up).In multivariable analysis, factors present at diagnosis associated with adverse visual outcomes included: multiple visual signs and symptoms (adjusted odds ratio [adjOR]: 8.33; 95% CI: 1.9-36.45), abnormal visual behavior (adjOR: 4.15; 95% CI: 1.20-14.34), new onset of visual symptoms (adjOR: 4.04; 95% CI: 1.26-12.95), and optic atrophy (adjOR: 3.73; 95% CI: 1.13-12.53). Squint, posterior visual pathway tumor involvement, and bilateral pathway tumor involvement showed borderline significance. Treatment appeared to reduce tumor size but improved vision in only 10/45 treated patients. Children with visual deterioration after primary observation are more likely to improve with treatment than children treated at diagnosis.

CONCLUSIONS

The analysis identified the importance of symptomatology, optic atrophy, and history of vision loss as predictive factors for poor visual outcomes in children with NF1-OPG.

Implications of new understandings of gliomas in children and adults with NF1: report of a consensus conference

Gliomas are the most common primary central nervous system tumors occurring in children and adults with neurofibromatosis type 1 (NF1). Over the past decade, discoveries of the molecular basis of low-grade gliomas (LGGs) have led to new approaches for diagnosis and treatments. However, these new understandings have not been fully applied to the management of NF1-associated gliomas. A consensus panel consisting of experts in NF1 and gliomas was convened to review the current molecular knowledge of NF1-associated low-grade “transformed” and high-grade gliomas; insights gained from mouse models of NF1-LGGs; challenges in diagnosing and treating older patients with NF1-associated gliomas; and advances in molecularly targeted treatment and potential immunologic treatment of these tumors. Next steps are recommended to advance the management and outcomes for NF1-associated gliomas.

Neurofibromatosis in the Era of Precision Medicine: Development of MEK Inhibitors and Recent Successes with Selumetinib

PURPOSE OF REVIEW

Patients with neurofibromatosis type 1 (NF1) are at increased risk for benign and malignant neoplasms. Recently, targeted therapy with the MEK inhibitor class has helped address these needs. We highlight recent successes with selumetinib while acknowledging ongoing challenges for NF1 patients and future directions.

RECENT FINDINGS

MEK inhibitors have demonstrated efficacy for NF1-related conditions, including plexiform neurofibromas and low-grade gliomas, two common causes of NF1-related morbidity. Active investigations for NF1-related neoplasms have benefited from advanced understanding of the genomic and cell signaling alterations in these conditions and development of sound preclinical animal models. Selumetinib has become the first FDA-approved targeted therapy for NF1 following its demonstrated efficacy for inoperable plexiform neurofibroma. Investigations of combination therapy and the development of a representative NF1 swine model hold promise for translating therapies for other NF1-associated pathology.

A Phase 2 Trial of Selumetinib in Children with Recurrent Optic Pathway and Hypothalamic Low-Grade Glioma without NF1: A Pediatric Brain Tumor Consortium Study

BACKGROUND

Pediatric low-grade gliomas (pLGGs) are the most common childhood brain tumor. Progression-free survival (PFS) is much lower than overall survival, emphasizing the need for alternative treatments. Sporadic (without neurofibromatosis type-1) optic pathway and hypothalamic glioma (OPHGs) are often multiply recurrent and cause significant visual deficits. Recently, there has been a prioritization of functional outcomes.

METHODS

We present results from children with recurrent/progressive OPHGs treated on a PBTC phase 2 trial evaluating efficacy of selumetinib, (AZD6244, ARRY-142886) a MEK-1/2 inhibitor. Stratum 4 of PBTC-029 included patients with sporadic recurrent/progressive OPHGs treated with selumetinib at the recommended phase 2 dose (25mg/m 2 /dose BID) for a maximum of 26 courses.

RESULTS

Twenty-five eligible and evaluable patients were enrolled with a median of 4 (1-11) previous therapies. Six of 25 (24%) had partial response, 14/25 (56%) had stable disease and 5 (20%) had progressive disease while on treatment. The median treatment courses were 26 (2-26); 14/25 patients completed all 26 courses. Two-year PFS was 78 ± 8.5%. Nineteen of 25 patients were evaluable for visual acuity which improved in 4/19 patients (21%), was stable in 13/19 (68%) and worsened in 2/19 (11%). Five of 19 patients (26%) had improved visual fields and 14/19 (74%) were stable. The most common toxicities were grade 1/2 CPK elevation, anemia, diarrhea, headache, nausea/emesis, fatigue, AST and ALT increase, hypoalbuminemia and rash.

CONCLUSIONS

Selumetinib was tolerable and led to responses and prolonged disease stability in children with recurrent/progressive OPHGs based upon radiographic response, PFS and visual outcomes.

A POETIC Phase II study of continuous oral everolimus in recurrent, radiographically progressive pediatric low-grade glioma

BACKGROUND

To evaluate efficacy, pharmacokinetics (PK) and pharmacodynamics of single-agent everolimus in pediatric patients with radiographically progressive low-grade glioma (LGG).

METHODS

Everolimus was administered at 5 mg/m² once daily as a tablet or liquid for a planned 48-week duration or until unacceptable toxicity or disease progression. Patients with neurofibromatosis type 1 were excluded. PK and pharmacodynamic endpoints were assessed in consenting patients.

RESULTS

Twenty-three eligible patients (median age 9.2 years) were enrolled. All patients received prior chemotherapy (median number of prior regimens two) and/or radiotherapy (two patients). By week 48, two patients had a partial response, 10 stable disease, and 11 clinical or radiographic progression; two discontinued study prior to 1 year (toxicity: 1, physician determination: 1). With a median follow up of 1.8 years (range 0.2-6.7 years), the 2-, 3-, and 5-year progression-free survivals (PFS) were 39 ± 11%, 26 ± 11%, and 26 ± 11%, respectively; two patients died of disease. The 2-, 3-, and 5-year overall survival (OS) were all 93 ± 6%. Grade 1 and 2 toxicities predominated; two definitively related grade 3 toxicities (mucositis and neutropenia) occurred. Grade 4 elevation of liver enzymes was possibly related in one patient. Predose blood levels showed substantial variability between patients with 45.5% below and 18.2% above the target range of 5-15 ng/mL. Pharmacodynamic analysis demonstrated significant inhibition in phospho-S6, 4E-BP1, and modulation of c-Myc expression.

CONCLUSION

Daily oral everolimus provides a well-tolerated, alternative treatment for multiple recurrent, radiographically progressive pediatric LGG. Based on these results, everolimus is being investigated further for this patient population.

Current Salvage Treatment Strategies for Younger Children (<10 y of Age) With Progressive Low-grade Glioma After Initial Chemotherapy in North America: A Web-based Survey

Pediatric low-grade gliomas (LGGs) are the most common brain tumors in children. Treatment of pediatric LGG can often be challenging, particularly when not resectable and refractory or recurrent following standard chemotherapy regimens. There is no current accepted standard of care salvage regimen for progressive LGG after the failure of first-line chemotherapy. A web-based survey was distributed to pediatric cancer centers throughout North America to inquire regarding institutional preferences of salvage treatment strategies after initial chemotherapy for LGG in children less than 10 years of age, as well as molecular testing preferences. Highlights from the survey results were as follows: vincristine/carboplatin (VC) and vinblastine (VBL) were the top 2 preferred salvage regimens for non-BRAF-altered pediatric LGG. BRAF and MEK inhibitors were the most preferred salvage regimens for BRAF V600e-mutated and BRAF fusion-positive pediatric LGG, respectively. VC ranked second. As high as 47.8% of North American centers would use conformal radiation for younger children with non-neurofibromatosis type 1 LGG after failing 2 to 3 chemotherapy regimens. Overall, 87% (87%) of North American institutions obtain some type of routine molecular testing for non-neurofibromatosis type 1-associated pediatric LGG cases. Less than 60% of centers obtain routine H3 K27M molecular testing for pediatric LGG with a midline location.

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.

New treatment modalities in NF-related neuroglial tumors

The management of low-grade gliomas (LGGs) and other neuroglial tumors in children with neurofibromatosis type 1 (NF1) has not changed over the past 2-3 decades. With the widespread utilization of chemotherapy for younger children with progressive LGGs, outcomes have been good for most patients who have required treatment. However, some may progress after the initiation of chemotherapy and others, although radiographically responding or with stable disease, may develop progressive neurologic and visual deterioration. Molecular-targeted therapy has become an option for patients who have progressed after receiving chemotherapy and the mTOR inhibitors and bevacizumab have already shown some degree of efficacy. However, the greatest impact has been the introduction of the MEK inhibitors. A variety of different MEK inhibitors are in clinical trials and have already demonstrated the ability to result in radiographic tumor shrinkage in the majority of children with NF1 and progressive LGGs. Because of this efficacy, the MEK inhibitors have moved rapidly from phase I studies to ongoing phase III studies comparing their benefit directly to that of chemotherapy. The long-term ability of these agents to not only control disease, but improve visual and/or neurological function, as well as their short- and long-term safety, are open questions that can only be answered by well-constructed prospective, often randomized, clinical trials.

Response assessment in paediatric low-grade glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group

Paediatric low-grade gliomas (also known as pLGG) are the most common type of CNS tumours in children. In general, paediatric low-grade gliomas show clinical and biological features that are distinct from adult low-grade gliomas, and the developing paediatric brain is more susceptible to toxic late effects of the tumour and its treatment. Therefore, response assessment in children requires additional considerations compared with the adult Response Assessment in Neuro-Oncology criteria. There are no standardised response criteria in paediatric clinical trials, which makes it more difficult to compare responses across studies. The Response Assessment in Pediatric Neuro-Oncology working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. We established a subcommittee to develop consensus recommendations for response assessment in paediatric low-grade gliomas. Final recommendations were based on literature review, current practice, and expert opinion of working group members. Consensus recommendations include imaging response assessments, with additional guidelines for visual functional outcomes in patients with optic pathway tumours. As with previous consensus recommendations, these recommendations will need to be validated in prospective clinical trials.

Loss of efficacy of subsequent nonsurgical therapy after primary treatment failure in pediatric low-grade glioma patients-Report from the German SIOP-LGG 2004 cohort

First-line treatment of pediatric low-grade glioma using surgery, radio- or chemotherapy fails in a relevant proportion of patients. We analyzed efficacy of subsequent surgical and nonsurgical therapies of the German cohort of the SIOP-LGG 2004 study (2004-2012, 1558 registered patients; median age at diagnosis 7.6 years, median observation time 9.2 years, overall survival 98%/96% at 5/10 years, 15% neurofibromatosis type 1 [NF1]). During follow-up, 1078/1558 patients remained observed without (n = 217), with 1 (n = 707), 2 (n = 124) or 3 to 6 (n = 30) tumor volume reductions; 480/1558 had 1 (n = 332), 2 (n = 80), 3 or more (n = 68) nonsurgical treatment-lines, accompanied by up to 4 tumor-reductive surgeries in 215/480; 265/480 patients never underwent any neurosurgical tumor volume reduction (163/265 optic pathway glioma). Patients with progressing tumors after first-line adjuvant treatment were at increased risk of suffering further progressions. Risk factors were young age (<1 year) at start of treatment, tumor dissemination or progression within 18 months after start of chemotherapy. Progression-free survival rates declined with subsequent treatment-lines, yet remaining higher for patients with NF1. In non-NF1-associated tumors, vinblastine monotherapy vs platinum-based chemotherapy was noticeably less effective when used as second-line treatment. Yet, for the entire cohort, results did not favor a certain sequence of specific treatment options. Rather, all can be aligned as a portfolio of choices which need careful balancing of risks and benefits. Future molecular data may predict long-term tumor biology.

The Use of MEK Inhibitors in Neurofibromatosis Type 1-Associated Tumors and Management of Toxicities

Early-phase clinical trials using oral inhibitors of MEK, the mitogen-activated protein kinase kinase, have demonstrated benefit for patients with neurofibromatosis type 1 (NF1)-associated tumors, particularly progressive low-grade gliomas and plexiform neurofibromas. Given this potential of MEK inhibition as an effective medical therapy, the use of targeted agents in the NF1 population is likely to increase substantially. For clinicians with limited experience prescribing MEK inhibitors, concern about managing these treatments may be a barrier to use. In this manuscript, the Clinical Care Advisory Board of the Children's Tumor Foundation reviews the published experience with MEK inhibitors in NF1 and outlines recommendations for side-effect management, as well as monitoring guidelines. These recommendations can serve as a beginning framework for NF providers seeking to provide the most effective treatments for their patients. IMPLICATIONS FOR PRACTICE: Neurofibromatosis type 1 (NF1) clinical care is on the cusp of a transformative shift. With the success of recent clinical trials using MEK inhibitors, an increasing number of NF1 patients are being treated with MEK inhibitors for both plexiform neurofibromas and low-grade gliomas. The use of MEK inhibitors is likely to increase substantially in NF1. Given these changes, the Clinical Care Advisory Board of the Children's Tumor Foundation has identified a need within the NF1 clinical community for guidance for the safe and effective use of MEK inhibitors for NF1-related tumors. This article provides a review of the published experience of MEK inhibitors in NF1 and provides recommendations for monitoring and management of side effects.

Late morbidity and mortality in adult survivors of childhood glioma with neurofibromatosis type 1: report from the Childhood Cancer Survivor Study

Purpose

Neurofibromatosis type 1 (NF1) is associated with tumor predisposition and non-malignant health conditions. Whether survivors of childhood cancer with NF1 are at increased risk for poor long-term health outcomes is unknown.

Methods

147 5+ year survivors of childhood glioma with NF1 from the Childhood Cancer Survivor Study were compared to 2 629 non-NF1 glioma survivors and 5 051 siblings for late mortality, chronic health conditions, psychosocial, neurocognitive, and socioeconomic outcomes.

Results

Survivors with NF1 (age at diagnosis: 6.8±4.8 years) had greater cumulative incidence of late mortality 30 years after diagnosis (46.3%[95% confidence interval: 23.9%−62.2%]) compared to non-NF1 survivors (18.0%[16.1%−20.0%]) and siblings (0.9%[0.6%−1.2%]), largely due to subsequent neoplasms. Compared to survivors without NF1, those with NF1 had more severe/life-threatening chronic conditions at cohort entry (46.3%[38.1%−54.4%] vs. 30.8%[29.1%−32.6%]), but similar rates of new conditions during follow-up (Rate Ratio: 1.26 [0.90–1.77]). Survivors with NF1 were more likely to report psychosocial impairments, neurocognitive deficits, and socioeconomic difficulties compared to survivors without NF1.

Conclusion

Late mortality among glioma survivors with NF1 is twice that of other survivors, due largely to subsequent malignancies. Screening, prevention and early intervention for chronic health conditions, psychosocial and neurocognitive deficits may reduce long-term morbidity in this vulnerable population.

Retrospective analysis of combination carboplatin and vinblastine for pediatric low-grade glioma

INTRODUCTION

Low-grade glioma (LGG) represent the most common pediatric central nervous system tumor. When total surgical resection is not feasible, chemotherapy is first-line therapy in children. Multiple pediatric LGG chemotherapy regimens have been investigated with variable 2-year event free survival (EFS) rates of 39-69%. To date, treatment of pediatric LGG with a carboplatin and vinblastine (C/VBL) chemotherapy regimen has only been evaluated in a phase 1 dose-finding study.

METHODS

A retrospective review of pediatric patients with LGG who were treated with C/VBL at Children's Hospital of Colorado or Akron Children's Hospital from 2011 to 2017 was conducted. Data collected included patient demographics, tumor location, disease response, neurofibromatosis 1 (NF1) status, therapy duration and toxicities. Response to therapy was determined by objective findings on imaging and treating physicians' evaluation.

RESULTS

Forty-six patients were identified for analysis, all of whom were chemotherapy-naive. Only five patients treated in this cohort had NF1. BRAF fusion was identified in 65% (22/34) of tested tumors. Best therapy response was partial response in nine patients and stable disease in twenty-five patients. Twelve patients had progressive disease. One-year, 3-year, and 5-year EFS probabilities for all patients were 69.6%, 39.4%, and 34.5%, respectively. Nine patients had admissions for febrile neutropenia and seven patients experienced one delay in chemotherapy due to neutropenia. Only two patients had to discontinue this chemotherapy regimen because of treatment-related toxicities [carboplatin allergy (n = 1) and vinblastine neuropathy (n = 1)].

CONCLUSION

C/VBL achieves similar EFS rates to other single-agent and combination cytotoxic chemotherapy regimens for pediatric LGG with manageable toxicities.