Comparison of epidemiology, treatments, and outcomes in pediatric versus adult ependymoma

Extraneural metastatic ependymoma: distant metastasis to the pleura, lungs, lymph nodes and bone

Ependymomas are neuroepithelial tumours arising from ependymal cells surrounding the cerebral ventricles that rarely metastasise to extraneural structures. This spread has been reported to occur to the lungs, lymph nodes, liver and bone. We describe the case of a patient with recurrent CNS WHO grade 3 ependymoma with extraneural metastatic disease. He was treated with multiple surgical resections, radiation therapy and salvage chemotherapy for his extraneural metastasis to the lungs, bone, pleural space and lymph nodes.

CBTRUS Statistical Report: American Brain Tumor Association & NCI Neuro-Oncology Branch Adolescent and Young Adult Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2016-2020

Recent analyses have shown that, whereas cancer survival overall has been improving, it has not improved for adolescents and young adults ages 15-39 years (AYA). The clinical care of AYA with primary brain and other central nervous system (CNS) tumors (BT) is complicated by the fact that the histopathologies of such tumors in AYA differ from their histopathologies in either children (ages 0-14 years) or older adults (ages 40+ years). The present report, as an update to a 2016 publication from the Central Brain Tumor Registry of the United States and the American Brain Tumor Association, provides in-depth analyses of the epidemiology of primary BT in AYA in the United States and is the first to provide biomolecular marker-specific statistics and prevalence by histopathology for both primary malignant and non-malignant BT in AYA. Between 2016 and 2020, the annual average age-specific incidence rate (AASIR) of primary malignant and non-malignant BT in AYA was 12.00 per 100,000 population, an average of 12,848 newly diagnosed cases per year. During the same period, an average of 1,018 AYA deaths per year were caused by primary malignant BT, representing an annual average age-specific mortality rate of 0.96 per 100,000 population. When primary BT were categorized by histopathology, pituitary tumors were the most common (36.6%), with an AASIR of 4.34 per 100,000 population. Total incidence increased with age overall; when stratified by sex, the incidence was higher in females than males at all ages. Incidence rates for all primary BT combined and for non-malignant tumors only were highest for non-Hispanic American Indian/Alaska Native individuals, whereas malignant tumors were more frequent in non-Hispanic White individuals, compared with other racial/ethnic groups. On the basis of histopathology, the most common molecularly defined tumor was diffuse glioma (an AASIR of 1.51 per 100,000). Primary malignant BT are the second most common cause of cancer death in the AYA population. Incidence rates of primary BT overall, as well as specific histopathologies, vary significantly by age. Accordingly, an accurate statistical assessment of primary BT in the AYA population is vital for better understanding the impact of these tumors on the US population and to serve as a reference for afflicted individuals, for researchers investigating new therapies, and for clinicians treating these patients.

Pediatric CNS tumors and 2021 WHO classification: what do oncologists need from pathologists?

The fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, established new approaches to both CNS tumor nomenclature and grading, emphasizing the importance of integrated diagnoses and layered reports. This edition increased the role of molecular diagnostics in CNS tumor classification while still relying on other established approaches such as histology and immunohistochemistry. Moreover, it introduced new tumor types and subtypes based on novel diagnostic technologies such as DNA methylome profiling. Over the past decade, molecular techniques identified numerous key genetic alterations in CSN tumors, with important implications regarding the understanding of pathogenesis but also for prognosis and the development and application of effective molecularly targeted therapies. This review summarizes the major changes in the 2021 fifth edition classification of pediatric CNS tumors, highlighting for each entity the molecular alterations and other information that are relevant for diagnostic, prognostic, or therapeutic purposes and that patients' and oncologists' need from a pathology report.

Ependymoma from Benign to Highly Aggressive Diseases: A Review

Ependymomas comprise biologically distinct tumor types with respect to age distribution, (epi)genetics, localization, and prognosis. Multimodal risk-stratification, including histopathological and molecular features, is essential in these biologically defined tumor types. Gross total resection (GTR), achieved with intraoperative monitoring and neuronavigation, and if necessary, second-look surgery, is the most effective treatment. Adjuvant radiation therapy is mandatory in high-risk tumors and in case of residual tumor. There is yet growing evidence that some ependymal tumors may be cured by surgery alone. To date, the role of chemotherapy is unclear and subject of current studies.Even though standard therapy can achieve reasonable survival rates for the majority of ependymoma patients, long-term follow-up still reveals a high probability of relapse in certain biological entities.With increasing knowledge of biologically distinct tumor types, risk-adapted adjuvant therapy gains importance. Beyond initial tumor control, and avoidance of therapy-induced morbidity for low-risk patients, intensified treatment for high-risk patients comprises another challenge. With identification of specific risk features regarding molecular alterations, targeted therapy may represent an option for individualized treatment modalities in the future.

Profiling spatiotemporal gene expression of the developing human spinal cord and implications for ependymoma origin

The spatiotemporal regulation of cell fate specification in the human developing spinal cord remains largely unknown. In this study, by performing integrated analysis of single-cell and spatial multi-omics data, we used 16 prenatal human samples to create a comprehensive developmental cell atlas of the spinal cord during post-conceptional weeks 5-12. This revealed how the cell fate commitment of neural progenitor cells and their spatial positioning are spatiotemporally regulated by specific gene sets. We identified unique events in human spinal cord development relative to rodents, including earlier quiescence of active neural stem cells, differential regulation of cell differentiation and distinct spatiotemporal genetic regulation of cell fate choices. In addition, by integrating our atlas with pediatric ependymomas data, we identified specific molecular signatures and lineage-specific genes of cancer stem cells during progression. Thus, we delineate spatiotemporal genetic regulation of human spinal cord development and leverage these data to gain disease insight.

Ependymomas

Ependymal neoplasms are a heterogenous group of neoplasms arising from the progenitors of the cells lining the ventricular system and the spinal central canal. During the last few years, significant novel data concerning oncogenesis, molecular characteristics and clinical correlations of these tumours have been collected, with a strong relevance for their pathological classification. The recently published 5th edition of WHO Classification of Central Nervous System Tumours integrates this novel knowledge and represents a substantial update compared to the previous edition. Concerning supratentorial ependymomas, the previous RELA fusion-positive ependymoma has been renamed into ZFTA fusion-positive and the novel YAP1 fusion-positive ependymoma subtype has been added. Posterior fossa ependymomas should now be allocated either to the Type A or Type B subtypes based on molecular profiling or using the H3 K27me3 immunohistochemical surrogate. Regarding spinal ependymomas, a novel subtype has been added based on a distinctive molecular trait, presence of MYCN amplification, and on the unfavourable outcome. Finally, myxopapillary ependymoma is now classified as a grade 2 tumour in accordance with its overall prognosis which mirrors that of conventional spinal ependymomas. The aim of this review is to present these changes and summarize the current diagnostic framework of ependymal tumours, according to the most recent updates.

Zebrafish Models of Paediatric Brain Tumours

Paediatric brain cancer is the second most common childhood cancer and is the leading cause of cancer-related deaths in children. Despite significant advancements in the treatment modalities and improvements in the 5-year survival rate, it leaves long-term therapy-associated side effects in paediatric patients. Addressing these impairments demands further understanding of the molecularity and heterogeneity of these brain tumours, which can be demonstrated using different animal models of paediatric brain cancer. Here we review the use of zebrafish as potential in vivo models for paediatric brain tumour modelling, as well as catalogue the currently available zebrafish models used to study paediatric brain cancer pathophysiology, and discuss key findings, the unique attributes that these models add, current challenges and therapeutic significance.

Redefining germline predisposition in children with molecularly characterized ependymoma: a population-based 20-year cohort

Ependymoma is the second most common malignant brain tumor in children. The etiology is largely unknown and germline DNA sequencing studies focusing on childhood ependymoma are limited. We therefore performed germline whole-genome sequencing on a population-based cohort of children diagnosed with ependymoma in Denmark over the past 20 years (n = 43). Single nucleotide and structural germline variants in 457 cancer related genes and 2986 highly evolutionarily constrained genes were assessed in 37 children with normal tissue available for sequencing. Molecular ependymoma classification was performed using DNA methylation profiling for 39 children with available tumor tissue. Pathogenic germline variants in known cancer predisposition genes were detected in 11% (4/37; NF2, LZTR1, NF1 & TP53). However, DNA methylation profiling resulted in revision of the histopathological ependymoma diagnosis to non-ependymoma tumor types in 8% (3/39). This included the two children with pathogenic germline variants in TP53 and NF1 whose tumors were reclassified to a diffuse midline glioma and a rosette-forming glioneuronal tumor, respectively. Consequently, 50% (2/4) of children with pathogenic germline variants in fact had other tumor types. A meta-analysis combining our findings with pediatric pan-cancer germline sequencing studies showed an overall frequency of pathogenic germline variants of 3.4% (7/207) in children with ependymoma. In summary, less than 4% of childhood ependymoma is explained by genetic predisposition, virtually restricted to pathogenic variants in NF2 and NF1. For children with other cancer predisposition syndromes, diagnostic reconsideration is recommended for ependymomas without molecular classification. Additionally, LZTR1 is suggested as a novel putative ependymoma predisposition gene.

Bromodomain and Extra-Terminal Protein Inhibitors: Biologic Insights and Therapeutic Potential in Pediatric Brain Tumors

Pediatric brain tumors have surpassed leukemia as the leading cause of cancer-related death in children. Several landmark studies from the last two decades have shown that many pediatric brain tumors are driven by epigenetic dysregulation within specific developmental contexts. One of the major determinants of epigenetic control is the histone code, which is orchestrated by a number of enzymes categorized as writers, erasers, and readers. Bromodomain and extra-terminal (BET) proteins are reader proteins that bind to acetylated lysines in histone tails and play a crucial role in regulating gene transcription. BET inhibitors have shown efficacy in a wide range of cancers, and a number have progressed to clinical phase testing. Here, we review the evidence for BET inhibitors in pediatric brain tumor experimental models, as well as their translational potential.

Essential Management of Pediatric Brain Tumors

Brain tumors are the most common solid tumors in children and are associated with high mortality. The most common childhood brain tumors are grouped as low-grade gliomas (LGG), high grade gliomas (HGG), ependymomas, and embryonal tumors, according to the World Health Organization (WHO). Advances in molecular genetics have led to a shift from pure histopathological diagnosis to integrated diagnosis. For the first time, these new criteria were included in the WHO classification published in 2016 and has been further updated in the 2021 edition. Integrated diagnosis is based on molecular genomic similarities of the tumor subclasses, and it can better explain the differences in clinical courses of previously histopathologically identical entities. Important advances have also been made in pediatric neuro-oncology. A growing understanding of the molecular-genetic background of tumorigenesis has improved the diagnostic accuracy. Re-stratification of treatment protocols and the development of targeted therapies will significantly affect overall survival and quality of life. For some pediatric tumors, these advances have significantly improved therapeutic management and prognosis in certain tumor subgroups. Some therapeutic approaches also have serious long-term consequences. Therefore, optimized treatments are greatly needed. Here, we discuss the importance of multidisciplinary collaboration and the role of (pediatric) neurosurgery by briefly describing the most common childhood brain tumors and their currently recognized molecular subgroups.

Do We Need Radiotherapy in Grade II Ependymoma?

Purpose/Objectives

The debate on whether radiotherapy (RT) is an essential part of primary treatment in patients with grade II ependymoma (G2E) is still ongoing, and this study aimed to evaluate its role.

Materials/Methods

A retrospective analysis of all the consecutive patients treated due to G2E in years 1985–2019 was performed. The group consisted of 116 patients with a small predominance of woman (55% vs. 45%) and the location of the tumor in the brain (58% vs. 42%). All had surgery as the primary treatment with 47% R0 resection. Radical RT was applied in 81 patients. In majority of cases (91%), patients received local irradiation.

Results

Median follow-up was 65 months, and during that time, 17 patients died. Five- and 10-year overall survival (OS) of the whole group was 87% and 83%. Radical surgery (R0 vs. R1/2) improved OS (p = 0.004), but the difference was observed only in patients with brain lesions (p = 0.01). Five- and 10-year progression-free survival (PFS) was 68% and 51%, respectively. Looking at the treatment of recurrence, those who received RT as a part of the treatment of the recurrent tumor had better OS (p = 0.048)—5- and 10-year OS of 85% and 78% vs. 66% and 57%. In the multivariate analysis, radical surgery (R0 vs. R1/2) and the use of RT in the primary treatment improved PFS (p = 0.006 and 0.007). Based on the location of the tumor, the positive influence of RT on PFS was observed only in the case of patients with brain tumors (p = 0.01). Also, comparing R1/2 surgery with R0 resection—the benefit of RT was only observed in R1/2 group (0.02).

Conclusions

RT in the case of patients with G2E is a valuable treatment of the recurrent disease. Patients with brain lesions after nonradical surgery might benefit from the local irradiation in terms of PFS.

An Insight into Pathophysiological Features and Therapeutic Advances on Ependymoma

Simple Summary

Although biological information and the molecular classification of ependymoma have been studied, the treatment systems for ependymoma are still insufficient. In addition, because the disease occurs infrequently, it is difficult to obtain sufficient data to conduct large-scale or randomized clinical trials. Therefore, this study is intended to emphasize the importance of understanding its pathological characteristics and prognosis as well as developing treatments for ependymoma through multilateral studies.

Abstract

Glial cells comprise the non-sensory parts of the central nervous system as well as the peripheral nervous system. Glial cells, also known as neuroglia, constitute a significant portion of the mammalian nervous system and can be viewed simply as a matrix of neural cells. Despite being the “Nervenkitt” or “glue of the nerves”, they aptly serve multiple roles, including neuron repair, myelin sheath formation, and cerebrospinal fluid circulation. Ependymal cells are one of four kinds of glial cells that exert distinct functions. Tumorigenesis of a glial cell is termed a glioma, and in the case of an ependymal cell, it is called an ependymoma. Among the various gliomas, an ependymoma in children is one of the more challenging brain tumors to cure. Children are afflicted more severely by ependymal tumors than adults. It has appeared from several surveys that ependymoma comprises approximately six to ten percent of all tumors in children. Presently, the surgical removal of the tumor is considered a standard treatment for ependymomas. It has been conspicuously evident that a combination of irradiation therapy and surgery is much more efficacious in treating ependymomas. The main purpose of this review is to present the importance of both a deep understanding and ongoing research into histopathological features and prognoses of ependymomas to ensure that effective diagnostic methods and treatments can be developed.

Pediatric ependymoma: an overview of a complex disease

Pediatric ependymomas comprise biologically distinct tumor entities with different (epi)genetics, age distribution and localization, as well as a different prognosis. Regarding risk stratification within these biologically defined entities, histopathological features still seem to be relevant. The mainstay of treatment is gross total resection (GTR) if possible, achieved with intraoperative monitoring and neuronavigation-and if necessary second surgery-followed by adjuvant radiation therapy. However, there is growing evidence that some ependymal tumors may be cured by surgery alone, while others relapse despite adjuvant treatment. To date, the role of chemotherapy is not clear. Current therapy achieves reasonable survival rates for the majority of ependymoma patients. The next challenge is to go beyond initial tumor control and use risk-adapted therapy to reduce secondary effect and therapy-induced morbidity for low-risk patients and to intensify treatment for high-risk patients. With identification of specific alterations, targeted therapy may represent an option for individualized treatment modalities in the future.

The role of sex genotype in paediatric CNS tumour incidence and survival

PURPOSE

Evidence exists, in CNS germinomas and medulloblastomas (MB), that patient sex significantly influences incidence and outcome. The role of sex genotype in other paediatric CNS tumours remains unclear. This study sought to examine the role of sex genotype in CNS tumour incidence and overall survival (OS).

METHODS

Age-adjusted incidence and OS rates were collected from the Surveillance Epidemiology and End Result (SEER) registry between 2000 and 2011 for common paediatric (<=19 years) CNS tumours: pilocytic astrocytoma (PA), anaplastic astrocytoma, glioblastoma (GBM), medulloblastoma, supratentorial CNS embryonal tumour, ependymoma, and germinoma. All patients with histologically confirmed, ICD-03 coded, first tumours, were included. Kaplan-Meier and Cox regression analyses were used to calculate hazard ratios (HR).

RESULTS

The total cases are as follows: males=3018 and females=2276. Highest incidence was seen in PA (n=2103). GBM displayed the worst OS, whilst PA displayed the best. Higher incidence was observed in males for all tumours, except PA. Females with ependymoma had significantly better OS compared to males, whereas males with germinomas had better OS compared to females. Females <1 year with AA had better OS than males. Increasing age significantly improved male and female survival in ependymoma and medulloblastoma.

CONCLUSION

Interrogating population-based registries such as SEER minimises bias and provides credible data. Observed differences in incidence and OS between the sexes for different paediatric CNS tumours provide useful prognostic information for clinicians. Sex genotype was a significant independent prognostic factor in ependymomas and germinomas. Further investigation of possible epigenetic and hormonal differences may provide sex-specific vulnerabilities that may be exploitable for targeted therapy.

Treatment trends and overall survival in patients with grade II/III ependymoma: The role of tumor grade and location

BACKGROUND

Treatment of ependymoma (EPN) is guided by associated tumor features, such as grade and location. However, the relationship between these features with treatments and overall survival in EPN patients remains uncharacterized. Here, we describe the change over time in treatment strategies and identify tumor characteristics that influence treatment and survival in EPN.

METHODS AND MATERIALS

Using the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 18 Registries (1973-2016) database, we identified patients with EPN microscopically confirmed to be grade II (EPN-GII) or III (EPN-GIII) tumors between 2004-2016. Overall survival (OS) was analyzed using Kaplan-Meier survival estimates and multivariable Cox proportional hazard models. A sub-analysis was performed by tumor location (supratentorial, posterior fossa, and spine). Change over time in rates of gross total resection (GTR), radiotherapy (RT), and chemotherapy (CS) were analyzed using linear regression, and predictors of treatment were identified using multivariable logistic regression models.

RESULTS

Between 2004-2016, 1,671 patients were diagnosed with EPN, of which 1,234 (74 %) were EPN-GII and 437 (26 %) EPN-GIII. Over the study period, EPN-GII patients underwent a less aggressive treatment (48 % vs 27 %, GTR; 60 % vs 30 %, RT; 22 % vs 2%, CS; 2004 vs 2016; p < 0.01 for all). Age, tumor size, location, and grade were positive predictors of undergoing treatment. Univariate analysis revealed that tumor grade and location were significantly associated with OS (p < 0.0001 for both). In multivariable Cox regression, tumor grade was an independent predictor of OS among patients in the cohort (grade III, HR 3.89 [2.84-5.33]; p < 0.0001), with this finding remaining significant across all tumor locations.

CONCLUSIONS

In EPN, tumor grade and location are predictors of treatment and overall survival. These findings support the importance of histologic WHO grade and location in the decision-making for treatment and their role in individualizing treatment for different patient populations.