Supratentorial and Infratentorial Ependymoma.

Ependymomas are the third most common intracranial tumor in children, presenting in both the supratentorial and infratentorial compartments. They may present in infants, young children, and adolescents with symptoms depending on size, location, and the age of the patient. The ideal imaging for evaluation and treatment is MRI. This is crucial for preoperative evaluation and planning, as well as postoperative assessment and evaluating the efficacy of treatment. Essentially without exception, aggressive surgery aimed at complete resection is the initial and most important factor in the long-term outcome of all these children. Histopathologic diagnosis for intracranial pediatric ependymoma has been narrowed to grade II and grade III, no longer characterized as classic and anaplastic. Subsequent conformal photon or proton beam irradiation is an established post-surgical therapy, with solid evidence that it benefits survival and offers lower toxicity to the normal brain of the young child. Although chemotherapeutic treatment has not been generally impactful, immunotherapeutic interventions may be on the horizon. Updated molecular subgrouping of ependymoma is changing the post-resection approach of these tumors with regard to both treatment and outcome. Excluding spinal ependymoma and subependymoma, there are four subtypes that are defined by genetic characteristics, two found in the supratentorial compartment, ST-EPN-YAP1 and ST-EPN-ZFTA, and two in the posterior fossa, PF-EPN-A and PF-EPN-B. Younger children harboring ZFTA fusion-positive supratentorial and type A posterior fossa tumors, regardless of histology, tend toward the poorest outcomes. On the contrary, older children with supratentorial YAP1 fusion-positive ependymomas and type B posterior fossa tumors may survive with surgery alone. The paradigm shift regarding the behavior of the various childhood ependymoma subtypes will hopefully lead to targeted, individualized therapies and improved outcomes.

Consensus guidelines for the management of posterior fossa tumour for low- and middle-income countries.

The posterior fossa is a limited compartment therefore lesions compressing its structures can result in devastating outcomes. It can cause significant neurological deficit due to mass effect on critical structures and hydrocephalus. Due to the nature of the infratentorial region, urgent surgical intervention is often the first-line option. Surgical neuro-oncologists guide patients and caregivers through the course of this disease and to inform them about the various options for management and long-term outcome optimisation. There is currently conflicting data; however, institutional experiences can guide us towards achieving improvements in surgical outcomes and quality of life. Advances in molecular classifications coupled with highdose radiation treatment improve our capacity for improving overall survival in these patients. Common childhood tumours are ependymomas, medulloblastomas, and juvenile pilocytic astrocytomas, while adults often present with metastases, and less commonly, cerebellar haemangioblastomas and gliomas. This paper outlines management strategies with consideration for multidisciplinary care and resourcelimited settings.

Consensus guidelines for the management of primary supra-tentorial intraventricular tumour for low- and middle-income countries.

Almost any primary or metastatic brain tumour can manifest in intraventricular (IV) locations. These tumours may either originate within the ventricular system or extend into the IV space through growth. Such neoplasms represent a broad spectrum, with supratentorial IV tumours forming a heterogeneous group. This group includes primary ependymal tumours, central neurocytomas, choroid plexus tumours, and notably, meningiomas, as well as a variety of non-neoplastic, benign, glial, and metastatic lesions that can secondarily invade the IV compartment. Often presenting with nonspecific symptoms, these tumours can lead to delayed medical attention. The diversity in potential diagnoses, combined with their deep and complex locations, poses significant management challenges. This paper aims to delineate optimal management strategies, underscoring the importance of multidisciplinary care, especially in settings with limited resources, to effectively navigate the complexities associated with treating intraventricular brain tumours.

Consensus guidelines for the management of intracranial ependymoma for low- and middle-income countries.

This paper presents comprehensive consensus guidelines for the management of intracranial ependymoma, neoplasms arising from ependymal cells in the central nervous system's ventricular system, in low- and middleincome countries (LMICs). Acknowledging the distinct epidemiological patterns of ependymomas, notably their higher incidence in paediatric patients, and variable survival rates, these guidelines emphasize tailored management approaches for different age groups. An expert panel, comprising specialists in neuro-oncology, convened to address gaps in diagnosis and management within LMICs, considering the varying clinical presentation based on tumour size and location. Emphasizing surgical intervention as the cornerstone of treatment, the guidelines also address challenges such as intraoperative bleeding and tumour location impacting complete resection. The role of molecular subgrouping in stratifying treatment and predicting prognosis is highlighted, alongside a careful consideration of radiotherapy timing, dose, and volume based on risk factors. Chemotherapy's role, especially in paediatric cases, is explored. The paper synthesizes current research and expert opinions, including the need for standardisation, genetic testing, and exploration of less invasive treatment modalities, to address the unique healthcare infrastructure challenges in LMICs. The guidelines also emphasize multidisciplinary teams, aiming to bridge the care gap between high-income countries and LMICs, and improve survival rates and quality of life for patients with intracranial ependymoma. This article serves as a valuable resource for clinicians, researchers, and policymakers in Pakistan and beyond, facilitating the development of evidence-based strategies in diverse healthcare settings.

Decoding pediatric spinal tumors: a single-center retrospective case series on etiology, presentation, therapeutic strategies, and outcomes.

INTRODUCTION: Spinal tumors (ST) often result in dire prognosis, carrying risks such as permanent paralysis, sensory loss, and sphincter dysfunction. Data on their incidence and etiology in pediatric populations are markedly scant. Our study investigates the etiology, clinical manifestation, treatment, and outcomes of pediatric ST. METHODS: We conducted a retrospective review of our institutional pediatric oncology and neurosurgery database, examining 14 patients under 18 years admitted with ST due to oncological diseases since 2005. We analyzed the clinical presentations, evaluations, molecular diagnostics and treatments for these patients. RESULTS: The study spanned 15 years and included 14 pediatric patients, each diagnosed with distinct spinal tumor entity. The mean patient age was approximately 19.6 ± 10.1 months. Severe axial pain along the vertebral column was observed in 13 patients, while acute neurological deterioration manifested in 7 patients. As a first-line intervention, 13 patients underwent decompressive surgery through laminectomy and tumor resection, and only one patient received chemotherapy solely. Before surgery, seven patients were unable to walk; post-surgery, six of them regained their ability to ambulate. The diagnosis encompassed a range of neoplasms: two instances of Ewing sarcoma, 3 instances of teratoma, one case presenting an atypical teratoid Rhabdoid tumor, two instances each of low-grade astrocytoma and neuroblastoma, and single instances of ependymoma, meningioma, rhabdomyosarcoma, and embryonal tumors with multilayered rosettes (ETMRs). Three patients succumbed two years after initiating therapy. CONCLUSION: Despite their rarity, intraspinal tumors in pediatric patients pose substantial therapeutic challenges. The intertwined complexities of the disease entity and the patient's neurological status demand swift initiation of an individualized therapeutic strategy. This crucial step helps optimize outcomes for this patient cohort, who frequently grapple with debilitating health conditions. Inclusion of these patients within a registry is mandatory to optimize treatment outcomes due to their rarity in pediatric population.

Survival Factors in 1580 Adults with Spinal Ependymoma: Insights from a Multicenter Oncology Database.

BACKGROUND: Using a multi-institutional oncology database, we investigate the survival rates and the impacts of demographic, clinical, and management characteristics on overall survival among adult patients diagnosed with spinal ependymoma. METHODS: Utilizing the SEER registry, patients with histologically or radiologically confirmed ependymomas were included. Factors impacting overall survival were analyzed using Kaplan-Meier survival curves and log-rank statistical analyses. RESULTS: A total of 1,580 patients were included. Their mean ± standard deviation age was 46.68 ± 15.96 years, and 51.1% were women. Gross total resection (GTR) was achieved in 66.4% of patients. The 5- and 10-year survival rates were 96.7% and 95.4%, respectively. A multivariable backward Cox regression showed that age ≥65 years was a significant predictor for mortality (hazard ratio [HR]: 3.93; 95% confidence interval [CI]: 2.21-7.00; P < 0.001). Likewise, tumor grade 3 (HR: 6.36; 95% CI: 1.95-20.76; P = 0.002), tumor grade 4 (HR: 7.74; 95% CI: 3.97-15.11; P < 0.001), presence of extra-neural metastasis (HR: 13.81; 95% CI: 3.67-51.96; P < 0.001), and receiving radiotherapy (HR: 2.50; 95% CI: 1.50-4.19; P < 0.001) were significant risk factors for mortality, while GTR was significantly associated with improved overall survival compared with subtotal resection or nonsurgical management (HR: 0.42; 95% CI: 0.25-0.73; P = 0.002). There were no significant effects for gender, race, marital status, income, residential area, chemotherapy, tumor size, and the presence of other benign or malignant tumors on the survival hazards (P > 0.05 for each). CONCLUSION: Early diagnosis and surgical management of spinal ependymomas, such as GTR, were associated with remarkable survival benefits. Old age, high-grade spinal ependymoma, and extra-neural metastasis were associated with worse overall survival, whereas radiotherapy's role remains unclear.

The medical and functional burden of surviving childhood ependymoma: A population-based study in Ontario, Canada.

BACKGROUND: Few studies have characterized the burden of late effects among childhood ependymoma survivors. To address this gap, we examined these sequelae using real-world health services data in a population-based ependymoma survivor cohort. METHODS: All individuals younger than 18 years diagnosed with an ependymoma in Ontario, Canada between 1987 and 2015 who had survived at least 5 years from their latest pediatric cancer event (index date) were matched 1:5 with population controls. Following linkage with provincial health services data, the cumulative incidences of multiple medical and functional outcomes between survivors and controls were compared. RESULTS: Among 96 survivors, 77.1% had been irradiated and 9.4% had received cisplatin. At 10 years post-index, survivors were at significantly higher risk of all-cause mortality (7.1%, 95% confidence interval [CI]: 1.0-13.3 vs. 0.3%, 95% CI: 0.0-1.0; p = .0002), non-obstetric hospitalization (45.1%, 95% CI: 32.6-56.7 vs. 10.6%, 95% CI: 7.6-14.1; p < .0001), stroke (6.5%, 95% CI: 2.3-13.7 vs. 0%; p < .0001), severe hearing loss requiring an amplification device (7.5%, 95% CI: 2.7-15.7 vs. 0%; p < .0001), receiving homecare service (27.6%, 95% CI: 18.5-37.5 vs. 7.7%, 95% CI: 5.3-10.7; p < .0001), and submitting a disability support prescription claim (24.0%, 95% CI: 14.8-34.3 vs. 5.4%, 95% CI: 3.5-7.8; p < .0001) compared to controls. CONCLUSIONS: Pediatric ependymoma survivors are highly vulnerable to severe late sequelae, including death, stroke, severe hearing loss, and disability. Urgent efforts are needed to improve risk-stratification approaches that mitigate exposure to toxic therapies for children with lower risk disease. Interventions to prevent or decrease the risk of developing late sequelae are critical to optimizing survivor long-term health.

Pediatric intramedullary spinal cord tumors: A national cancer database analysis of demographics, patterns of care, and survival.

OBJECTIVE: Query the National Cancer Database (NCDB) to delineate epidemiologic frequency, care patterns, and survival outcomes of pediatric intramedullary spinal cord tumors (IMSCTs). METHODS: IMSCTs included ependymoma, astrocytoma, and hemangioblastoma. We examined data from the NCDB spanning 2004-2018, focusing on IMSCT in children aged 0-21 years. Our analysis included logistic and Poisson regression, Kaplan-Meier survival estimates, and Cox proportional hazards models. RESULTS: This study included 1066 patients aged 0-21 years. 59.4 % of patients were male, while 83.1 % were white. The most common tumor histology was ependymoma (57.5 %), followed by astrocytoma (36.1 %) and hemangioblastoma (6.4 %). 24.9 % of patients received radiotherapy, with radiotherapy utilization being highest among patients aged 6-10 years. Chemotherapy utilization was highest in patients aged 0-5 years. 87.2 % of patients underwent surgical resection, with higher rates in patients aged 16-21 years. Overall survival did not differ significantly between resected and non-resected patients (p = 0.315). Patients in rural areas had worse OS than those in metro areas (HR = 4.42, p = 0.048). Patients with astrocytoma had worse OS compared to other histologies (HR = 2.21, p = 0.003). Astrocytoma patients were over twice as likely to have prolonged LOS compared to ependymoma patients (OR = 2.204, p < 0.001). CONCLUSIONS: In summary, our analysis utilizing the NCDB database provides a comprehensive overview of demographics, care patterns, and outcomes for the largest cohort of pediatric IMSCTs to date. These insights underscore the complexity of managing IMSCTs and emphasize the need for tailored approaches to improve patient outcomes.

Impact of Molecular Subgroups on Prognosis and Survival Outcomes in Posterior Fossa Ependymomas: A Retrospective Study of 412 Cases.

BACKGROUND AND OBJECTIVES: Posterior fossa ependymomas (PFEs) are rare brain tumors classified as PF-EPN-A (PFA) and PF-EPN-B (PFB) subgroups. The study aimed to evaluate the prognosis and survival outcomes in PFEs, with a focus on the impact of molecular subgroups. METHODS: A retrospective study was conducted on 412 patients with PFEs. Kaplan-Meier survival analyses were conducted to evaluate the overall survival (OS) and progression-free survival. Cox regression analyses were conducted to assess the prognostic factors. A nomogram was developed to predict the OS rates of PFEs. RESULTS: The study revealed significant differences between PFA and PFB in patient and tumor characteristics. PFAs were associated with poorer OS (hazard ratios [HR] 3.252, 95% CI 1.777-5.950, P < .001) and progression-free survival (HR 4.144, 95% CI 2.869-5.985, P < .001). World Health Organization grade 3 was associated with poorer OS (HR 2.389, 95% CI 1.236-4.617, P = .010). As for treatment patterns, gross total resection followed by radiotherapy or the combination of radiotherapy and chemotherapy yielded the most favorable OS for PFA ( P = .025 for both), whereas gross total resection followed by radiotherapy rather than observation showed improved OS for PFB ( P = .046). The nomogram demonstrated a high degree of accuracy and discrimination capacity for the prediction of OS rates for up to 10 years. In addition, 6 cases of PFA (3.51%) with H3K27M mutations were identified. CONCLUSION: PFAs demonstrate worse prognosis and survival outcomes compared with PFBs. Both PFAs and PFBs necessitate maximal resection followed by intensive adjuvant therapies in long-term effects.

Recurrence Patterns and Surveillance Imaging in Pediatric Brain Tumor Survivors.

Surveillance magnetic resonance imaging (MRI) is routinely used to detect recurrence in pediatric central nervous system (CNS) tumors. The frequency of neuroimaging surveillance varies without a standardized approach. A single-institutional retrospective cohort study evaluated the frequency of recurrences. This study included 476 patients with the majority diagnosed with low-grade glioma (LGG) (n=138, 29%), high-grade glioma (HGG) (n=77, 16%), ependymoma (n=70, 15%), or medulloblastoma (n=61, 13%). LGG, HGG, and ependymoma patients more commonly had multiply recurrent disease ( P =0.08), with ependymoma patients demonstrating ≥2 relapses in 47% of cases. Recurrent disease was identified by imaging more often than clinical symptoms (65% vs. 32%; P =<0.01). Patients diagnosed with meningioma demonstrated the longest mean time to first relapse (74.7 mo) whereas those with atypical teratoid rhabdoid tumor and choroid plexus carcinoma tended to have the shortest time to relapse (8.9 and 9 mo, respectively). Overall, 22 patients sustained first relapse >10 years from initial diagnosis. With a higher tendency toward detection of tumor recurrence/progression on MRI surveillance in comparison to clinical progression, surveillance imaging is necessary in routine follow up of pediatric CNS tumor survivors. With some relapses >10 years from initial diagnosis, imaging beyond this time point may be useful in particular tumor types. While the study is limited in outcome analysis, earlier detection of recurrence would lead to earlier initiation of treatment and implementation of salvage treatment regimens which can impact survival and quality of life.

Development of Chromosome 1q+ Specific Treatment for Highest Risk Pediatric Posterior Fossa Ependymoma.

PURPOSE: There are no effective treatment strategies for children with highest-risk posterior fossa group A ependymoma (PFA). Chromosome 1q gains (1q+) are present in approximately 25% of newly diagnosed PFA tumors, and this number doubles at recurrence. Seventy percent of children with chromosome 1q+ PFA will die because of the tumor, highlighting the urgent need to develop new therapeutic strategies for this population. EXPERIMENTAL DESIGN: In this study, we utilize 1q+ PFA in vitro and in vivo models to test the efficacy of combination radiation and chemotherapy in a preclinical setting. RESULTS: 5-fluorouracil (5FU) enhances radiotherapy in 1q+ PFA cell lines. Specifically, 5FU increases p53 activity mediated by the extra copy of UCK2 located on chromosome 1q in 1q+ PFA. Experimental downregulation of UCK2 resulted in decreased 5FU sensitivity in 1q+ PFA cells. In in vitro studies, a combination of 5FU, retinoid tretinoin (ATRA), and radiation provided the greatest reduction in cellular proliferation and greatest increase in markers of apoptosis in 1q+ PFA cell lines compared with other treatment arms. Similarly, in vivo experiments demonstrated significant enhancement of survival in mice treated with combination radiation and 5FU and ATRA. CONCLUSIONS: These results are the first to identify a chromosome 1q+ specific therapy approach in 1q+ PFA. Existing phase I studies have already established single-agent pediatric safety and dosages of 5FU and ATRA, allowing for expedited clinical application as phase II trials for children with high-risk PFA.

Association Between Urbanicity and Outcomes Among Patients with Spinal Cord Ependymomas in the United States.

BACKGROUND: Spinal cord ependymomas (SCEs) represent the most common intramedullary spinal cord tumors among adults. Research shows that access to neurosurgical care and patient outcomes can be greatly influenced by patient location. This study investigates the association between the outcomes of patients with SCE in metropolitan and nonmetropolitan areas. METHODS: Cases of SCE between 2004 and 2019 were identified within the Central Brain Tumor Registry of the United States, a combined dataset including the Centers for Disease Control and Prevention's National Program of Cancer Registries and National Cancer Institute's Surveillance, Epidemiology, and End Results Program data. Multivariable logistic regression models were constructed to evaluate the association between urbanicity and SCE treatment, adjusted for age at diagnosis, sex, race and ethnicity. Survival data was available from 42 National Program of Cancer Registries (excluding Kansas and Minnesota, for which county data are unavailable), and Cox proportional hazard models were used to understand the effect of surgical treatment, county urbanicity, age at diagnosis, and the interaction effect between age at diagnosis and surgery, on the survival time of patients. RESULTS: Overall, 7577 patients were identified, with 6454 (85%) residing in metropolitan and 1223 (15%) in nonmetropolitan counties. Metropolitan and nonmetropolitan counties had different age, sex, and race/ethnicity compositions; however, demographics were not associated with differences in the type of surgery received when stratified by urbanicity. Irrespective of metropolitan status, individuals who were American Indian/Alaska Native non-Hispanic and Hispanic (all races) were associated with reduced odds of receiving surgery. Individuals who were Black non-Hispanic and Hispanic were associated with increased odds of receiving comprehensive treatment. Diagnosis of SCE at later ages was linked with elevated mortality (hazard ratio = 4.85, P < 0.001). Gross total resection was associated with reduced risk of death (hazard ratio = 0.37, P = 0.004), and age did not interact with gross total resection to influence risk of death. CONCLUSIONS: The relationship between patients' residential location and access to neurosurgical care is critical to ensuring equitable distribution of care. This study represents an important step in delineating areas of existing disparities.

Intracranial ependymoma in an adult patient with multiple primary malignancies.

The incidence of multiple primary malignancies (MPM) is increasing, and therefore, it has become highly important for clinicians to consider the concept of MPM when treating oncology patients. In this case report, we follow the clinical course of a patient diagnosed with a new intracranial lesion, an ependymoma, on a background of MPM. We explore the barriers implicating the delay in her diagnosis, dissect the challenges in managing her disease and emphasise the importance of social determinants in optimising her care.

Tumors of Choroid Plexus and Other Ventricular Tumors.

Tumors arising inside the ventricular system are rare but represent a difficult diagnostic and therapeutic challenge. They usually are diagnosed when reaching a big volume and tend to affect young children. There is a wide broad of differential diagnoses with significant variability in anatomical aspects and tumor type. Differential diagnosis in tumor type includes choroid plexus tumors (papillomas and carcinomas), ependymomas, subependymomas, subependymal giant cell astrocytomas (SEGAs), central neurocytomas, meningiomas, and metastases. Choroid plexus tumors, ependymomas of the posterior fossa, and SEGAs are more likely to appear in childhood, whereas subependymomas, central neurocytomas, intraventricular meningiomas, and metastases are more frequent in adults. This chapter is predominantly focused on choroid plexus tumors and radiological and histological differential diagnosis. Treatment is discussed in the light of the modern acquisition in genetics and epigenetics of brain tumors.

Latest classification of ependymoma in the molecular era and advances in its treatment: a review.

Ependymoma is a rare central nervous system (CNS) tumour occurring in all age groups and is one of the most common paediatric malignant brain tumours. Unlike other malignant brain tumours, ependymomas have few identified point mutations and genetic and epigenetic features. With advances in molecular understanding, the latest 2021 World Health Organization (WHO) classification of CNS tumours divided ependymomas into 10 diagnostic categories based on the histology, molecular information and location; this accurately reflected the prognosis and biology of this tumour. Although maximal surgical resection followed by radiotherapy is considered the standard treatment method, and chemotherapy is considered ineffective, the validation of the role of these treatment modalities continues. Although the rarity and long-term clinical course of ependymoma make designing and conducting prospective clinical trials challenging, knowledge is steadily accumulating and progress is being made. Much of the clinical knowledge obtained from clinical trials to date was based on the previous histology-based WHO classifications, and the addition of new molecular information may lead to more complex treatment strategies. Therefore, this review presents the latest findings on the molecular classification of ependymomas and advances in its treatment.

Recent Advancements in Ependymoma: Challenges and Therapeutic Opportunities.

BACKGROUND: Ependymoma is one of the most common malignant pediatric brain tumors and can be difficult to treat. Over the last decade, much progress has been made in the understanding of the underlying molecular drivers within this group of tumors, but clinical outcomes remain unchanged. SUMMARY: Here, we review the most recent molecular advances in pediatric ependymoma, evaluate results of recent clinical trials and discuss the ongoing challenges in the field and questions that remain. KEY MESSAGES: The field of ependymoma has vastly changed over the last several decades with ten distinct molecular subgroups now described, but much progress needs to be made in developing new therapeutic strategies and targets.

[Pediatric Intracranial Ependymoma - Recommendations for First-Line Treatment from the German HIT-MED study group]. / Kinder und Jugendliche mit intrakraniellem Ependymom ­ Empfehlungen der HIT-MED-Studiengruppe der GPOH zur Erstlinientherapie.

Biological subtypes of ependymoma (EPN) have been introduced by the recent WHO classification and appear to have great impact on the clinical course, but have not yet found their way into clinical risk stratification. Further, the overall unfavorable prognosis underlines the fact that current therapeutic strategies need further evaluation for improvement. To date, there is no international consensus regarding first-line treatment for children with intracranial EPN. Extent of resection is known to be the most important clinical risk factor, leading to the consensus that consequent evaluation for re-surgery of postoperative residual tumor needs to have highest priority. Furthermore, efficacy of local irradiation is unquestioned and recommended for patients aged>1 year. In contrast, efficacy of chemotherapy is still under discussion. The European trial SIOP Ependymoma II aims at evaluating efficacy of different chemotherapy elements, leading to the recommendation to include German patients. The BIOMECA study, as biological accompanying study, aims at identifying new prognostic parameters. These results might help to develop targeted therapies for unfavorable biological subtypes. For patient who are not qualified for inclusion into the interventional strata, the HIT-MED Guidance 5.2 provides specific recommendations. This article is meant as an overview of national guidelines regarding diagnostics and treatment as well as of treatment according to the SIOP Ependymoma II trial protocol.

Why haven't we solved intracranial pediatric ependymoma? Current questions and barriers to treatment advances.

Pediatric intracranial ependymoma has seen a recent exponential expansion of biological findings, rapidly dividing the diagnosis into several subgroups, each with specific molecular and clinical characteristics. While such subdivision may complicate clinical conclusions from historical trials, this knowledge also provides an opportunity for interrogating the major clinical and biological questions preventing near-term translation into effective therapy for children with ependymoma. In this article, we briefly review some of the most critical clinical questions facing both patient management and the construct of future trials in childhood ependymoma, as well as explore some of the current barriers to efficient translation of preclinical discovery to the clinic.

Adult intracranial ependymoma-relevance of DNA methylation profiling for diagnosis, prognosis, and treatment.

BACKGROUND: A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain unclear. Here, we retrospectively evaluate the impact of surgery and radiotherapy on outcome after molecular reclassification of adult intracranial ependymomas. METHODS: Tumors diagnosed as intracranial ependymomas from 170 adult patients collected from 8 diagnostic institutions were subjected to DNA methylation profiling. Molecular classes, patient characteristics, and treatment were correlated with progression-free survival (PFS). RESULTS: The classifier indicated an ependymal tumor in 73.5%, a different tumor entity in 10.6%, and non-classifiable tumors in 15.9% of cases, respectively. The most prevalent molecular classes were posterior fossa ependymoma group B (EPN-PFB, 32.9%), posterior fossa subependymoma (PF-SE, 25.9%), and supratentorial ZFTA fusion-positive ependymoma (EPN-ZFTA, 11.2%). With a median follow-up of 60.0 months, the 5- and 10-year-PFS rates were 64.5% and 41.8% for EPN-PFB, 67.4% and 45.2% for PF-SE, and 60.3% and 60.3% for EPN-ZFTA. In EPN-PFB, but not in other molecular classes, gross total resection (GTR) (P = .009) and postoperative radiotherapy (P = .007) were significantly associated with improved PFS in multivariable analysis. Histological tumor grading (WHO 2 vs. 3) was not a predictor of the prognosis within molecularly defined ependymoma classes. CONCLUSIONS: DNA methylation profiling improves diagnostic accuracy and risk stratification in adult intracranial ependymoma. The molecular class of PF-SE is unexpectedly prevalent among adult tumors with ependymoma histology and relapsed as frequently as EPN-PFB, despite the supposed benign nature. GTR and radiotherapy may represent key factors in determining the outcome of EPN-PFB patients.