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

Pediatric gliomas immunity challenges and immunotherapy advances

Pediatric gliomas, the most frequent brain tumors in children, are characterized by heterogeneity and a unique tumor immune microenvironment. They are categorized into different subtypes, including low-grade gliomas like pilocytic astrocytomas and high-grade gliomas such as diffuse midline gliomas and diffuse intrinsic pontine gliomas, each exhibiting distinct immunological profiles. The tumor immune microenvironment in pediatric gliomas is shaped by cellular and non-cellular components, including immune cells, cytokines, and the extracellular matrix, involved in tumor progression, immune evasion, and response to therapy. While pediatric low-grade gliomas often display an immunosuppressed microenvironment, high-grade gliomas are characterized by complex immune infiltrates and intricate immunosuppressive mechanisms. The blood-brain barrier further obscures immune cell recruitment and therapeutic delivery. Despite advances in understanding adult gliomas, the immunobiology of pediatric tumors is poorly investigated, with limited data on the interactions between glioma cells and immune populations such as T and natural killer cells, as well as tumor-associated macrophages. Herein, we provide an update of the current knowledge on tumor immune microenvironment interactions in pediatric gliomas, highlighting the immunosuppressive mechanisms and emerging immunotherapeutic strategies aiming at overcoming these barriers to improve clinical outcomes for affected children.

A year in pharmacology: new drugs approved by the US Food and Drug Administration in 2024

The US Food and Drug Administration approved 50 new drugs and nine new cellular and gene therapy products in 2024, i.e., a total of 59 new medical therapies. The latter group represented three treatments each for oncology and hematology/immunotherapy, and one each for neurology, genetic disorders, and cardiovascular disorders. Oncology, hematology/immunotherapy, and neurological disorders (14, six, and seven, respectively) also were highly prevalent among classic medications. Looking at trends over the past 5 years, we observe a greater share in first-in-class medications, more fast-track approvals, and mRNA/gene/cell-based therapies. While small molecules remain the largest fraction, their percentage has been declining substantially over the past 5 years. Taking together, these findings testify to the commitment of the pharmaceutical industry for innovative treatments, including conditions for which no approved therapies existed. On the other hand, there also is a trend for approvals for narrowly focused conditions such as tumors defined by genetic alterations.

Multimodal contrastive learning for enhanced explainability in pediatric brain tumor molecular diagnosis

Despite the promising performance of convolutional neural networks (CNNs) in brain tumor diagnosis from magnetic resonance imaging (MRI), their integration into the clinical workflow has been limited. That is mainly due to the fact that the features contributing to a model's prediction are unclear to radiologists and hence, clinically irrelevant, i.e., lack of explainability. As the invaluable sources of radiologists' knowledge and expertise, radiology reports can be integrated with MRI in a contrastive learning (CL) framework, enabling learning from image-report associations, to improve CNN explainability. In this work, we train a multimodal CL architecture on 3D brain MRI scans and radiology reports to learn informative MRI representations. Furthermore, we integrate tumor location, salient to several brain tumor analysis tasks, into this framework to improve its generalizability. We then apply the learnt image representations to improve explainability and performance of genetic marker classification of pediatric Low-grade Glioma, the most prevalent brain tumor in children, as a downstream task. Our results indicate a Dice score of 31.1% between the model's attention maps and manual tumor segmentation (as an explainability measure) with test classification performance of 87.7%, significantly outperforming the baselines. These enhancements can build trust in our model among radiologists, facilitating its integration into clinical practices for more efficient tumor diagnosis.

Epidemiology and Clinical Outcomes of Childhood Central Nervous System Cancers in a Large Low/Middle-Income Country Pediatric Oncology Center: A Report on 5,051 Kids

BACKGROUND

Central nervous system (CNS) tumors are the leading cause of cancer-related deaths in children. Although most cases come from low- and middle-income countries (LMIC) where their prognosis is worse, few epidemiologic studies are conducted in these regions.

METHODS

We conducted a registry-based cohort study for childhood CNS tumors at Children's Cancer Hospital, Egypt, over 15 years. Unified treatment protocols were implemented. Survival analyses were conducted using the Kaplan-Meier function. Cases were additionally annotated using the International Classification of Childhood Cancer-3 classification.

RESULTS

In total, 5,051 children ≤18 years of age were identified, accounting for 20% of all childhood cancers treated at Children's Cancer Hospital, Egypt. The most common tumor sites were the posterior fossa (36.8%) and brainstem (17.7%). Pathologies were predominantly astrocytic (n = 1,360; 26.9%) and embryonal (n = 1,003; 19.9%) in origin. The 5-year overall survival (OS) and event-free survival for all cases were 64.6% and 51.8%, respectively. More specifically, 1,421 low-grade gliomas were identified, with a 5-year OS of 91.1%. Medulloblastoma (n = 801) recorded a 5-year OS of 66%. The entity with the worst prognosis was diffuse intrinsic pontine glioma (n = 633), with a 5-year OS of 3.2%.

CONCLUSIONS

We report on a large number of childhood CNS tumors from an LMIC. This study underscores the need to understand the burden of childhood brain tumors and its outcomes in resource-constrained settings.

IMPACT

This study reports on the epidemiology and clinical outcomes of 5,000+ children with CNS tumors from a specialized LMIC center. Despite the lack of many sophisticated and advanced facilities, LMICs can improve the clinical end-results with experience and augmented efforts.

Artificial Intelligence for Neuroimaging in Pediatric Cancer

BACKGROUND/OBJECTIVES

Artificial intelligence (AI) is transforming neuroimaging by enhancing diagnostic precision and treatment planning. However, its applications in pediatric cancer neuroimaging remain limited. This review assesses the current state, potential applications, and challenges of AI in pediatric neuroimaging for cancer, emphasizing the unique needs of the pediatric population.

METHODS

A comprehensive literature review was conducted, focusing on AI's impact on pediatric neuroimaging through accelerated image acquisition, reduced radiation, and improved tumor detection. Key methods include convolutional neural networks for tumor segmentation, radiomics for tumor characterization, and several tools for functional imaging. Challenges such as limited pediatric datasets, developmental variability, ethical concerns, and the need for explainable models were analyzed.

RESULTS

AI has shown significant potential to improve imaging quality, reduce scan times, and enhance diagnostic accuracy in pediatric neuroimaging, resulting in improved accuracy in tumor segmentation and outcome prediction for treatment. However, progress is hindered by the scarcity of pediatric datasets, issues with data sharing, and the ethical implications of applying AI in vulnerable populations.

CONCLUSIONS

To overcome current limitations, future research should focus on building robust pediatric datasets, fostering multi-institutional collaborations for data sharing, and developing interpretable AI models that align with clinical practice and ethical standards. These efforts are essential in harnessing the full potential of AI in pediatric neuroimaging and improving outcomes for children with cancer.

Efficacy and safety of dabrafenib plus trametinib in pediatric versus adult gliomas: a systematic review and meta-analysis

BACKGROUND

The clinical course and therapeutic outcomes of pediatric and adult gliomas vary. Dabrafenib plus trametinib is a new therapeutic option for the management of gliomas. This study aimed to compare the outcomes of co-administration of dabrafenib and trametinib in pediatric and adult gliomas.

METHODS

Systematic search was conducted in four electronic databases encompassing Pubmed, Embase, Scopus, and Web of Science. Publications that assessed the role of dabrafenib plus trametinib in adults or pediatrics were included.

RESULTS

Eight studies with 243 individuals, encompassing 161 pediatrics and 82 adults, were included in our study. We demonstrated that despite a higher objective response rate (ORR) (53% [95% CI, 44-61%] vs. 39% [95% CI, 26-54%], P = 0.11) and clinical benefit rate (CBR) (87% [95% CI, 72-95%] vs. 73% [95% CI, 54-86%], P = 0.16) among pediatrics, the difference was insignificant. We exhibited that younger age, BRAF V600 mutation, and longer therapy periods were accompanied by better radiological outcomes among pediatrics, and the female gender was correlated with better radiological results in adults. Our findings showed that the pooled adverse event (AE) rate was 96% (95% CI, 69-100%) in pediatrics and 83% (95% CI, 42-97%) among adults; however, there was no meaningful difference (P = 0.30).

CONCLUSION

Co-administration of dabrafenib and trametinib is accompanied by promising results among pediatrics and adults diagnosed with glioma. However, the comparison results should be interpreted meticulously due to limitations that may affect the generalizability of the findings.

The role of MEK inhibition in pediatric low-grade gliomas

Pediatric low-grade gliomas (pLGGs) are the most common brain tumors in children. Many patients with unresectable tumors experience recurrence or long-term sequelae from standard chemotherapeutics. This mini-review explores the emerging role of MEK inhibitors in the management of pLGGs, highlighting their potential to transform current treatment paradigms. We review the molecular basis for therapeutic MEK inhibition in the context of pLGG, provide an evidence base for the use of the major MEK inhibitors currently available in the market for pLGG, and review the challenges in the use of MEKi inhibitors in this population.

Treatment Options for IDH-Mutant Malignant Gliomas

OPINION STATEMENT

As the peak incidence of isocitrate dehydrogenase (IDH)-mutant gliomas is amongst young adults, there is a need to balance tumor control with long term side effects of therapy. Following initial clinical presentation and acquisition of contrasted diagnostic imaging, tissue diagnosis is essential in suspected diffuse glioma. Depending on the location and extent of disease, maximal surgical resection is preferred both for histologic diagnosis and initial therapy. Partial resection or biopsy alone is considered when the tumor cannot be completely resected or if there are clinical reservations regarding a more significant operation. The classification of diffuse glioma has evolved over time, with histopathology and molecular marker status guiding discussions of prognosis and postoperative management. In patients with IDH-mutant grade 2 glioma and low-risk features, observation with active surveillance is generally recommended following a gross total resection. For those with high-risk features, which historically included age > 40 years or subtotal resection, adjuvant chemotherapy and radiation therapy are generally recommended, however decisions for adjuvant therapy pose challenges as many of the landmark historical trials guiding adjuvant therapy were performed prior to the molecularly defined era. This is an area where multiple clinical trials are ongoing and hold promise to inform treatment paradigms, including recent data on the use of IDH-mutant inhibitors in grade 2 tumors with recurrent or residual disease. For IDH-mutant grade 3 and 4 glioma, adjuvant chemotherapy and radiation are recommended for all patients after initial resection.

Towards a Risk-Based Follow-Up Surveillance Imaging Schedule for Children and Adolescents with Low-Grade Glioma

The frequency and duration of imaging surveillance in children and adolescents with pediatric low-grade gliomas (pLGGs) aims for the early detection of recurrence or progression. Although surveillance of pLGGs is performed routinely, it is not yet standardized. The aim of the current review is to provide a comprehensive synthesis of published studies regarding the optimal frequency, intervals, and duration of surveillance. Several key influencing factors were identified (age, the extent of resection, the tumor location, the histological type, and specific molecular characteristics). However, the lack of consistent definitions of recurrence/progression and the extent of resection meant that it was not possible to perform a meta-analysis of the data from the 18 included articles. This review highlights the need for updating the definition of these terms for uniform and global use both in routine clinical practice as well as in upcoming trials. Thus, future studies on the heterogenous group of pLGGs will allow for the better tailoring of both the frequency and duration of imaging surveillance protocols in relevant settings.

Type II RAF inhibitor tovorafenib for the treatment of pediatric low-grade glioma

INTRODUCTION

Pediatric low-grade glioma (pLGG) is the most prevalent childhood brain tumor group, currently regarded as a chronic disease. On 23 April 2024, the U.S. FDA approved a new type II RAF inhibitor, tovorafenib (OJEMDATM), previously known as DAY101, for the treatment of patients aged 6 months and older with relapsed or refractory (R/R) pLGG harboring a BRAF fusion or rearrangement, or BRAF V600E mutation.

AREAS COVERED

This article aims to review the pharmacological properties of tovorafenib and evaluate its efficacy and safety in the treatment of R/R pLGG. We conducted a systematic search of PubMed and Web of Science databases for English-language publications related to tovorafenib, including journal articles and conference abstracts, up through 20 August 2024.

EXPERT OPINION

As the first and only FDA-approved medicine for children with BRAF fusions or rearrangements, which are the most common molecular alteration in pLGG, tovorafenib shows superior central nervous system penetration without the paradoxical activation of the MAPK pathway reported for type I BRAF inhibitors. Phase 1 and the pivotal phase 2 trials have demonstrated that tovorafenib monotherapy is generally well-tolerated and exhibits encouraging signs of meaningful, rapid and sustained clinical activity in children and young adults with BRAF-altered pLGG.

Population-level 5-year event-free survival for children with cancer in Australia

BACKGROUND

Event-free survival (EFS) considers other adverse events in addition to mortality. It therefore provides a more complete understanding of the effectiveness and consequences of treatment than standard survival measures, but is rarely reported at the population level for childhood cancer.

PROCEDURE

Our study cohort (n = 7067) was obtained from the Australian Childhood Cancer Registry, including children aged under 15 diagnosed with cancer between 2006 and 2015, with follow-up potentially available to 31 December 2020. The events of interest were relapse following remission, progressive disease, diagnosis of a second primary cancer or death from any cause. Five-year EFS and all-cause observed survival were both calculated, stratified by type of childhood cancer, remoteness of residence and stage at diagnosis. Differences in EFS were assessed using multivariable flexible parametric models.

RESULTS

Approximately one quarter of patients (n = 1605 of 7067, 23%) experienced at least one of the events of interest within 5 years of diagnosis. Relapse was twice as common for children with metastatic/advanced disease (22%) versus children with localised/limited cancers (11%). Overall 5-year EFS was 75.0% (95% confidence interval [CI]: 73.9%-76.0%), compared to 85.8% observed survival (95% CI: 85.0%-86.6%). Patients with other gliomas had the lowest EFS (35.4%, 95% CI: 27.8%-43.1%). EFS was significantly lower among children with acute myeloid leukaemia in outer regional/remote areas compared to major cities (adjusted hazard ratio [HR] = 1.90, 95% CI: 1.20-3.00).

CONCLUSIONS

Reporting EFS at a population level provides further insight on a wider range of impacts apart from mortality alone, contributing towards efforts to improve the management and outcomes of childhood cancer.

Molecular markers for pediatric low-grade glioma

Over the past decade, our understanding of the molecular drivers of pediatric low-grade glioma (PLGG) has expanded dramatically. These tumors are predominantly driven by RAS/MAPK pathway activating alterations (fusions and point mutations), most frequently in BRAF, FGFR1, and NF1. Furthermore, additional second hits in tumor suppressor genes (TP53, ATRX, CDKN2A) can portend more aggressive behaviour. Accordingly, comprehensive molecular profiling-specifically genetic sequencing, often plus copy number profiling-has become critical for guiding the diagnosis and management of PLGG. In this review, we discuss the most important genetic alterations that inform on classification and prognosis of PLGG, highlighting their diagnostic and therapeutic relevance.

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.

The role of surgery for optic pathway gliomas in the era of precision medicine

Optic pathway gliomas (OPGs) represent a unique subset of brain tumours that primarily affect the paediatric population. Traditionally, these tumours are managed conservatively due to their location to and association with vital structures. This article explores the evolving role of surgery in the management of OPGs, particularly in the context of advancements in precision medicine. The advent of targeted therapy, especially for tumours with specific genetic alterations, such as BRAF V600E mutations, has revolutionized the treatment landscape, offering new avenues for patient-specific therapy. However, surgery still plays a crucial role, especially for debulking in cases of hydrocephalus or when standard therapies are ineffective. Advances in surgical techniques, including neuronavigation, endoscopic approaches, and intraoperative neurophysiological monitoring, have enhanced the safety and efficacy of operative interventions. Despite these developments, the complexity of OPGs necessitates a multidisciplinary approach, focusing on long-term outcomes and quality of life. Future research is needed to further elucidate the role of surgery in an era increasingly dominated by molecular genetics and targeted therapies.

Long-term quality of survival after pediatric low-grade glioma

BACKGROUND

Low-grade glioma is the most common brain tumor in children with different modes of treatment and a high overall survival. Low-grade glioma is considered a chronic disease, since residual tumor is present in many children. The tumor and its treatment lead to acquired brain injury with diverse consequences for later life based on factors like the diverse tumor locations, treatment(s) applied, neurofibromatosis type 1, and age at diagnosis.

METHODS

An overview of affected domains is provided based upon cohort studies from literature and partially based on clinical experience with a practical approach regarding each domain of functioning in order to provide insight in the requirements for long-term care assistance after childhood low-grade glioma.

RESULTS

The diverse domains that can potentially be affected are described as follows: motor function, speech, eating and swallowing, sensory functions, seizures, neuropathy, organ function after systemic treatment, late effects due to cranial radiation (vascular changes and secondary tumors, endocrine and hypothalamic function, sleep and energy, neuro-cognition and education, psychosocial effects, and quality of life.

CONCLUSION

Insight in affected domains guides advices for medical follow-up, diagnostics, supportive instructions, and assistive measures per domain of functioning and provide insight in the requirements for long-term care assistance after childhood low-grade glioma.

Role of surgery in the treatment of pediatric low-grade glioma with various degrees of brain stem involvement

OBJECTIVE

Posterior fossa pediatric low-grade glioma involving the brainstem and cerebellar peduncles (BS-pLGG) are a subgroup with higher risks at surgery. We retrospectively analyzed the role of surgery in the interdisciplinary armamentarium of treatment options in our institutional series of BS-pLGG with various degrees of brainstem involvement.

MATERIAL AND METHODS

We analyzed data of 52 children with BS-pLGG after surgical intervention for clinical/molecular characteristics, neurological outcome, factors influencing recurrence/progression pattern, and tumor volumetric analysis of exclusively surgically treated patients to calculate tumor growth velocity (TGV). Tumors were stratified according to primary tumor origin in four groups: (1) cerebellar peduncle, (2) 4th ventricle, (3) pons, (4) medulla oblongata.

RESULTS

The mean FU was 6.44 years. Overall survival was 98%. The mean PFS was 34.07 months. Two patients had biopsies only. Fifty-two percent of patients underwent remission or remained in stable disease (SD) after initial surgery. Patients with progression underwent further 23 resections, 15 chemotherapies, 4 targeted treatments, and 2 proton radiations. TGV decreased after the 2nd surgery compared to TGV after the 1st surgery (p < 0.05). The resection rates were significantly higher in Groups 1 and 2 and lowest in medulla oblongata tumors (Group 4) (p < 0.05). More extended resections were achieved in tumors with KIAA1549::BRAF fusion (p = 0.021), which mostly occurred in favorable locations (Groups 1 and 2). Thirty-one patients showed postoperatively new neurological deficits. A total of 27/31 improved within 12 months. At the end of FU, 6% had moderate deficits, 52% had mild deficits not affecting activities, and 36% had none. Fifty percent of patients were free of disease or showed remission, 38% were in SD, and 10% showed progression.

CONCLUSION

The first surgical intervention in BS-pLGG can control disease alone in overall 50% of cases, with rates differing greatly according to location (Groups 1 > 2 > 3 > 4), with acceptable low morbidity. The second look surgery is warranted except in medullary tumors. With multimodality treatments almost 90% of patients can obtain remission or stable disease after > 5 years of follow-up. An integrated multimodal and multidisciplinary approach aiming at minimal safe residual disease, combining surgery, chemo-, targeted therapy, and, as an exception, radiation therapy, is mandatory.

Paediatric low-grade glioma: the role of classical pathology in integrated diagnostic practice

Low-grade gliomas are a cause of severe and often life-long disability in children. Pathology plays a key role in their management by establishing the diagnosis, excluding malignant alternatives, predicting outcomes and identifying targetable genetic alterations. Molecular diagnosis has reshaped the terrain of pathology, raising the question of what part traditional histology plays. In this review, we consider the classification and pathological diagnosis of low-grade gliomas and glioneuronal tumours in children by traditional histopathology enhanced by the opportunities afforded by access to comprehensive genetic and epigenetic characterisation.

Role of intraoperative ultrasound and MRI to aid grade of resection of pediatric low-grade gliomas: accumulated experience from 4 centers

PURPOSE

Pediatric low-grade gliomas (pLGG) are the most common brain tumors in children and achieving complete resection (CR) in pLGG is the most important prognostic factor. There are multiple intraoperative tools to optimize the extent of resection (EOR). This article investigates and discusses the role of intraoperative ultrasound (iUS) and intraoperative magnetic resonance imaging (iMRI) in the surgical treatment of pLGG.

METHODS

The tumor registries at Tuebingen, Rome and Pretoria were searched for pLGG with the use of iUS and data on EOR. The tumor registries at Liverpool and Tuebingen were searched for pLGG with the use of iMRI where preoperative CR was the surgical intent. Different iUS and iMRI machines were used in the 4 centers.

RESULTS

We included 111 operations which used iUS and 182 operations using iMRI. Both modalities facilitated intended CR in hemispheric supra- and infratentorial location in almost all cases. In more deep-seated tumor location like supratentorial midline tumors, iMRI has advantages over iUS to visualize residual tumor. Functional limitations limiting CR arising from eloquent involved or neighboring brain tissue apply to both modalities in the same way. In the long-term follow-up, both iUS and iMRI show that achieving a complete resection on intraoperative imaging significantly lowers recurrence of disease (chi-square test, p < 0.01).

CONCLUSION

iUS and iMRI have specific pros and cons, but both have been proven to improve achieving CR in pLGG. Due to advances in image quality, cost- and time-efficiency, and efforts to improve the user interface, iUS has emerged as the most accessible surgical adjunct to date to aid and guide tumor resection. Since the EOR has the most important effect on long-term outcome and disease control of pLGG in most locations, we strongly recommend taking all possible efforts to use iUS in any surgery, independent of intended resection extent and iMRI if locally available.

Applications of machine learning to MR imaging of pediatric low-grade gliomas

INTRODUCTION

Machine learning (ML) shows promise for the automation of routine tasks related to the treatment of pediatric low-grade gliomas (pLGG) such as tumor grading, typing, and segmentation. Moreover, it has been shown that ML can identify crucial information from medical images that is otherwise currently unattainable. For example, ML appears to be capable of preoperatively identifying the underlying genetic status of pLGG.

METHODS

In this chapter, we reviewed, to the best of our knowledge, all published works that have used ML techniques for the imaging-based evaluation of pLGGs. Additionally, we aimed to provide some context on what it will take to go from the exploratory studies we reviewed to clinically deployed models.

RESULTS

Multiple studies have demonstrated that ML can accurately grade, type, and segment and detect the genetic status of pLGGs. We compared the approaches used between the different studies and observed a high degree of variability throughout the methodologies. Standardization and cooperation between the numerous groups working on these approaches will be key to accelerating the clinical deployment of these models.

CONCLUSION

The studies reviewed in this chapter detail the potential for ML techniques to transform the treatment of pLGG. However, there are still challenges that need to be overcome prior to clinical deployment.

Current challenges in the treatment of gliomas: The molecular era

Gliomas originate from glial cells in the central nervous system. Approximately 80%-85% of malignant brain tumors in adults are gliomas. The most common central nervous system tumor in children is low-grade pediatric glioma. Diagnosis was determined by histological features until 2016 when the World Health Organization classification integrated molecular data with anatomopathological information to achieve a more integral diagnosis. Molecular characterization has led to better diagnostic and prognostic staging, which in turn has increased the precision of treatment. Current efforts are focused on more effective therapies to prolong survival and improve the quality of life of adult and pediatric patients with glioma. However, improvements in survival have been modest. Currently, clinical guidelines, as well as the article by Mohamed et al accompanying this editorial piece, are adapting treatment recommendations (surgery, chemotherapy, and radiotherapy) according to diagnosis and prognosis guided by molecular biomarkers. Furthermore, this paves the way for the design of clinical trials with new therapies, which is especially important in pediatric gliomas.

Pediatric hemispheric cerebellar low-grade gliomas: clinical approach, diagnosis, and management challenges-experience at a tertiary care children's hospital

PURPOSE

This study aims to provide an exhaustive analysis of pediatric low-grade gliomas (pLGGs) in the cerebellar hemispheres, focusing on incidence, clinical characteristics, surgical outcomes, and prognosis. It seeks to enhance understanding and management of pLGGs in the pediatric population.

METHODS

We conducted an observational, descriptive, retrospective, and cross-sectional study at a pediatric hospital, reviewing medical records of 30 patients with cerebellar hemispheric pLGGs treated from December 2014 to January 2023. Data collection included demographics, clinical presentation, imaging findings, surgical approach, postoperative complications, histopathological diagnosis, hydrocephalus management, and follow-up. Molecular markers and adjuvant therapies were also analyzed.

RESULTS

The cohort predominantly presented with cerebellar symptoms, with 60% showing hydrocephalus at diagnosis. MRI with gadolinium was crucial for diagnosis. Surgical focus was on achieving gross total resection (GTR), accomplished in 70% of cases. Postsurgical hydrocephalus was less common, and cerebellar mutism was not reported. While a complete molecular analysis was not performed in all cases, available data suggest significant influence of molecular markers on prognosis and therapeutic options of pLGGs.

CONCLUSIONS

This study highlights the unique clinical and molecular characteristics of cerebellar hemispheric pLGGs in children. The lower incidence of postoperative hydrocephalus and absence of cerebellar mutism are notable findings. Emphasizing a multidisciplinary approach, our findings contribute to a deeper understanding of pediatric pLGGs, underscoring the need for personalized treatment strategies and vigilant follow-up.

Tovorafenib: First Approval

Tovorafenib (OJEMDA™) is a once-weekly oral, selective, brain-penetrant, type II RAF kinase inhibitor being developed by Day One Biopharmaceuticals, Inc., under a license from Takeda Oncology, for the treatment of paediatric low-grade glioma (pLGG) and solid tumours. Most pLGGs harbour alterations in the MAPK pathway, such as a BRAF mutation or BRAF fusion, which result in aberrant intracellular signalling. Tovorafenib is an inhibitor of mutant BRAF V600E, wild-type BRAF and wild-type CRAF kinases and BRAF fusions. In April 2024, tovorafenib received its first approval in the USA for the treatment of patients aged ≥ 6 months with relapsed or refractory pLGGs harbouring a BRAF fusion or rearrangement, or BRAF V600 mutation. It received accelerated approval for this indication based on the response rate and duration of response achieved in this population in the ongoing, pivotal, phase 2 FIREFLY-1 study. Clinical development of tovorafenib is underway in numerous countries worldwide. This article summarizes the milestones in the development of tovorafenib leading to this first approval for relapsed or refractory pLGG with an activating BRAF alteration.

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.

Development and validation of a nomogram to predict overall survival in patients with glioma: a population-based study

AIM

The objective is to investigate the prognostic factors associated with gliomas and to develop and assess a predictive nomogram model connected to survival that may serve as an additional resource for the clinical management of glioma patients.

METHOD

From 2010 to 2015, participants included in the study were chosen from the Surveillance Epidemiology and End Results (SEER) database. Gliomas were definitively diagnosed in each of them. They were divided into the training group and the validation cohort at random (7/3 ratio) using a random number table. To identify the independent predictive markers for overall survival (OS), Cox regression analysis was utilized. Subsequently, the training cohort's survival-related nomogram predictive model for OS was created by incorporating the fundamental patient attributes. Following that, the training cohort's model underwent internal validation. The nomogram model's authenticity and reliability were assessed through the computation of receiver operating characteristic (ROC) curves and concordance index (C-index). To evaluate the degree of agreement between the observed and predicted values in the training and validation cohorts, calibration plots were created.

RESULT

Age, primary site, histological type, surgery, chemotherapy, marital status, and grade were the independent predictive factors for OS in the training cohort, according to Cox regression analysis. Moreover, the nomogram model for predicting 1-year, 3-year, and 5-year OS was built using these variables. The C-indexes of OS for glioma patients in the training cohort and internal validation cohort were found to be 0.779 (95% CI=0.769-0.789) and 0.776 (95% CI=0.760-0.792), respectively, according to the results. The ROC curves also demonstrated good discrimination. Additionally, calibration plots demonstrated a fair amount of agreement.

CONCLUSIONS

In summary, the nomogram prediction model of OS demonstrated a moderate level of reliability in its predictive performance, offering valuable reference data to enable doctors to quickly and easily determine the survival likelihood of patients with gliomas.

Hypoxia-induced activation of HIF-1alpha/IL-1beta axis in microglia promotes glioma progression via NF-κB-mediated upregulation of heparanase expression

BACKGROUND

Glioma is a common tumor that occurs in the brain and spinal cord. Hypoxia is a crucial feature of the tumor microenvironment. Tumor-associated macrophages/microglia play a crucial role in the advancement of glioma. This study aims to illuminate the detailed mechanisms by which hypoxia regulates microglia and, consequently, influences the progression of glioma.

METHODS

The glioma cell viability and proliferation were analyzed by cell counting kit-8 assay and 5-ethynyl-2'-deoxyuridine assay. Wound healing assay and transwell assay were implemented to detect glioma cell migration and invasion, respectively. Enzyme-linked immunosorbent assay was conducted to detect protein levels in cell culture medium. The protein levels in glioma cells and tumor tissues were evaluated using western blot analysis. The histological morphology of tumor tissue was determined by hematoxylin-eosin staining. The protein expression in tumor tissues was determined using immunohistochemistry. Human glioma xenograft in nude mice was employed to test the influence of hypoxic microglia-derived interleukin-1beta (IL-1β) and heparanase (HPSE) on glioma growth in vivo.

RESULTS

Hypoxic HMC3 cells promoted proliferation, migration, and invasion abilities of U251 and U87 cells by secreting IL-1β, which was upregulated by hypoxia-induced activation of hypoxia inducible factor-1alpha (HIF-1α). Besides, IL-1β from HMC3 cells promoted glioma progression and caused activation of nuclear factor-κB (NF-κB) and upregulation of HPSE in vivo. We also confirmed that IL-1β facilitated HPSE expression in U251 and U87 cells by activating NF-κB. Hypoxic HMC3 cells-secreted IL-1β facilitated the proliferation, migration, and invasion of U251 and U87 cells via NF-κB-mediated upregulation of HPSE expression. Finally, we revealed that silencing HPSE curbed the proliferation and metastasis of glioma in mice.

CONCLUSION

Hypoxia-induced activation of HIF-1α/IL-1β axis in microglia promoted glioma progression via NF-κB-mediated upregulation of HPSE expression.