Natural history and role of radiation in patients with supratentorial and infratentorial WHO grade II ependymomas: results from a population-based study

Prognostic factors of pediatric ependymomas at a National Cancer Reference Center in Peru

Background

Ependymomas are central nervous system tumors that significantly impact the quality of life and carry a high mortality rate. Both the disease itself and its treatment cause significant morbidity. At a national level in Peru, there are no reports on clinical characteristics of the disease.

Methods

This retrospective study captured patient aged less than 19 years with a diagnosis of ependymoma from 2012 to 2022 at a tertiary center in Lima.

Results

85 patients were included with a median follow-up time was 51.6 months. The 5-year overall survival and progression-free survival were 55.89% (95% CI: 44.28 - 65.99) and 37.71% (95% CI: 26,21-49,16) respectively. The main prognostic factors identified were completed treatment (p=0.019), adjuvant chemotherapy (p=0.048), presence of metastasis (p=0.012), and disease recurrence (p=0.02).

Conclusions

The survival of patients with ependymoma is below that reported in high-income countries. Incomplete treatment and treatment abandonment are factors that negatively impact the prognosis. Further studies are needed to identify barriers in the referral and treatment process for patients with ependymoma.

Survival After Resection of Newly-Diagnosed Intracranial Grade II Ependymomas: An Initial Multicenter Analysis and the Logistics of Intraoperative Magnetic Resonance Imaging

OBJECTIVE

To identify factors, including the use of intraoperative magnetic resonance imaging (iMRI), impacting overall survival (OS) and progression-free survival (PFS) after resections of newly diagnosed intracranial grade II ependymomas performed across 4 different institutions.

METHODS

Analyses of a multicenter mixed retrospective/prospective database assessed the impact of patient, treatment, and tumor characteristics on OS and PFS. iMRI workflow and logistics were also outlined.

RESULTS

Forty-three patients were identified (mean age 25.4 years, mean follow-up 52.8 months). The mean OS was 52.8 ± 44.7 months. Univariate analyses failed to identify prognostic factors associated with OS, likely due to relatively shorter follow-up time for this less aggressive glioma subtype. The mean PFS was 43.7 ± 39.8 months. Multivariate analyses demonstrated that gross-total resection was associated with prolonged PFS compared to both subtotal resection (STR) (P = 0.005) and near-total resection (P = 0.01). Infratentorial location was associated with improved PFS compared to supratentorial location (P = 0.04). Log-rank analyses of Kaplan-Meier survival curves showed that increasing extent of resection (EOR) led to improved OS specifically for supratentorial tumors (P = 0.02) and improved PFS for all tumors (P < 0.001). Thirty cases (69.8%) utilized iMRI, of which 12 (27.9%) involved additional resection after iMRI. Of these, 8/12 (66.7%) resulted in gross-total resection, while 2/12 (16.7%) were near-total resection and 2/12 (16.7%) were subtotal resection. iMRI was not an independent prognosticator of PFS (P = 0.72).

CONCLUSIONS

Greater EOR and infratentorial location were associated with increased PFS for grade II ependymomas. Greater EOR was associated with longer OS only for supratentorial tumors. A longer follow-up is needed to establish prognostic factors for this cohort, including use of iMRI.

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.

Molecular Classification and Therapeutic Targets in Ependymoma

Ependymoma is a biologically diverse tumor wherein molecular classification has superseded traditional histological grading based on its superior ability to characterize behavior, prognosis, and possible targeted therapies. The current, updated molecular classification of ependymoma consists of ten distinct subgroups spread evenly among the spinal, infratentorial, and supratentorial compartments, each with its own distinct clinical and molecular characteristics. In this review, the history, histopathology, standard of care, prognosis, oncogenic drivers, and hypothesized molecular targets for all subgroups of ependymoma are explored. This review emphasizes that despite the varied behavior of the ependymoma subgroups, it remains clear that research must be performed to further elucidate molecular targets for these tumors. Although not all ependymoma subgroups are oncologically aggressive, development of targeted therapies is essential, particularly for cases where surgical resection is not an option without causing significant morbidity. The development of molecular therapies must rely on building upon our current understanding of ependymoma oncogenesis, as well as cultivating transfer of knowledge based on malignancies with similar genomic alterations.

Pediatric ependymoma: A single-center experience from a developing country

Background

Ependymomas are the third most common pediatric central nervous system (CNS) tumors, accounting for 6-12% of brain tumors in children. Management of these tumors remains challenging and recurrence occurs in over 50% of cases, mainly when complete resection is not achieved before radiotherapy. The 5-year overall survival (OS) ranges from 39 to 64%, with a 5-year progression-free survival (PFS) rate of 23-45%. The study aimed to describe the OS and PFS rates of cases of pediatric ependymoma. It also aimed to evaluate the effects of different variables on disease outcomes. Variables examined included patient age, the extent of surgical resection, radiotherapy and chemotherapy delivered, the histopathological subtype of the tumor, primary tumor location, and extent of the disease at presentation. Last, the challenges that potentially compromise treatment outcomes in resource-limited countries were to be highlighted.

Methods

This is a retrospective cohort study, representing a single-center experience that included 47 pediatric patients treated at the National Cancer Institute, Cairo University, between January 2009 and December 2014.

Results

Median follow-up stood at 23.5 months (range: 2-77 months). The average 3-year OS and PFS rates were 43.7 and 43.3%, respectively.

Conclusion

The extent of surgical excision (maximal resection) and the adequacy of postoperative radiotherapy were the only two factors that had significantly affected the outcome. Understandably, treatment outcomes for ependymomas in developing countries still lag behind best reported outcomes, mainly due to inadequate surgical excision and postoperative radiotherapy.

Pediatric Cancer

In pediatric brain tumors, the intensification of chemotherapy has allowed for a reduction in radiotherapy (RT) volume to an involved field approach, particularly in patients with medulloblastoma. For patients with low-grade gliomas, the trend has remained to delay RT with chemotherapy; however, when RT is used, typically smaller clinical target volume margins are used. For patients with extracranial tumors, intensive chemotherapy to address systemic disease with local control is considered standard. Proton beam therapy shows significant promise in addressing both short-term and long-term toxicities in both central nervous system (CNS) and non-CNS pediatric tumors.

The mediating role of extent of resection in the relationship between the tumor characteristics and survival outcome of glioma

The prognostic value of tumor characteristics for glioma has been controversial, partly because of a lack of knowledge about how these associations develop. Extent of resection may be factors that mediate the relationship between tumor characteristics and the hazard of death from glioma.

Patients and Methods: This consecutive study retrospectively included a group of 393 treatment-naive patients with newly, pathologically confirmed glioma between January 2004 and December 2014. Information on patient age, gender, Karnofsky Performance Status (KPS), tumor grade, tumor size, tumor location, presence or absence of contrast enhancement on MRI and extent of tumor resection have all been collected. The discrete-time survival model integrating survival outcomes within structural equation models was employed to develop and evaluate a comprehensive hypothesis regarding the direct and indirect impact of tumor characteristics on the hazard of death from glioma, mediated by the extent of resection.

Results: Except for tumor location, the indirect effects of tumor grade, contrast enhancement, and tumor size on PFS of glioma through extent of resection were found significant in the model.

Conclusion: This study provides a better understanding of the process through which tumor characteristics is associated with hazard of death from glioma.

The role of postoperative radiotherapy in pediatric patients with grade II intracranial ependymomas: a population-based, propensity score-matched study

Purpose

The main objectives of this study were to clarify the efficacy of postoperative radiotherapy (PORT) for pediatric intracranial grade II ependymomas (EPNs) and to explore whether various characteristics are associated with different outcomes in patients with and without PORT.

Patients and methods

Data from patients younger than 18 years diagnosed with grade II intracranial EPNs and treated by surgery, with or without PORT, were obtained from the Surveillance, Epidemiology, and End Results (SEER) database (1973–2013 data set). Propensity score-matched analysis was conducted to balance clinical variables. Patient characteristics were stratified and analyzed.

Results

In total, data from 632 patients with grade II EPNs treated by cancer-directed surgery with or without PORT were obtained from the SEER database. Multivariable Cox analysis in the matched cohort suggested that undergoing PORT (overall survival [OS], P=0.020; cancer-specific survival [CSS], P=0.031), undergoing gross total resection (GTR; subtotal resection [STR] vs GTR; OS, P<0.001; CSS, P<0.001), and older age (OS, P<0.001; CSS, P<0.001) were the independent predictors of superior prognosis. Stratified analysis demonstrated that patient characteristics, including infratentorial location, younger age, and STR, were associated with benefit from PORT, while the survival advantage was not detected in patients who underwent GTR.

Conclusion

Propensity score-matched analysis using SEER data indicates survival advantages of PORT. Given the strong prognostic associations with extent of resection and patient age, we recommend PORT for younger patients treated by STR.

Pediatric Supratentorial Ependymoma: Surgical, Clinical, and Molecular Analysis

BACKGROUND

Pediatric supratentorial ependymomas (SEs) have distinct molecular and behavioral differences from their infratentorial counterparts.

OBJECTIVE

To present our experience with pediatric SEs over a 24-yr period.

METHODS

Clinical, operative, and radiographic information was abstracted retrospectively. Our primary outcomes were progression-free survival (PFS) and overall survival (OS). Detection of C11orf95-RELA rearrangement was performed using interphase fluorescence in situ hybridization (iFISH).

RESULTS

Seventy-three patients were identified (41 female, 32 male); median age was 6.7 yrs (range, 1 mo-18.8 yr); median follow-up was 8.3 yrs (range, 2.0-26.3). Fifty-eight (79.5%) of 73 patients underwent gross total resection (GTR); no patient with subtotal resection had greater than 1 cm3 of residual tumor; 42 patients (57.5%) experienced subsequent disease progression with 17 patients ultimately dying of their disease. Median PFS was 3.7 yrs. Molecular analysis was available for 51 patients (70%). On bivariate analysis, PFS and OS were not statistically affected by age, tumor grade, or extent of resection, although there was a clinically significant trend for the latter in favor of aggressive resection on PFS (P = .061). Children with RELA fusion had significantly higher PFS (P = .013) than those without, although there was no difference in OS when compared with those with no C11orf95-RELA fusion or C11orf95 gene rearrangement alone.

CONCLUSION

In our series, GTR may be associated with better PFS, but did not impact OS. Surprisingly, RELA fusion was not found to be a negative prognostic factor, raising the possibility that the deleterious effects may be overcome by aggressive resection.

Treatment Decisions of World Health Organization Grade II and III Ependymomas in Molecular Era

Surgery and radiotherapy are mainstays of treatment for ependymomas (EPNs). Recent molecular subgrouping could be superior to histopathological grading for predicting the prognosis of patients with EPNs. Gross total resection is an effective treatment approach regardless of its locations or pathologic grades. Adjuvant therapeutic strategies could be decided based on molecular subgrouping with risk-stratification. Information of histologic-molecular biology is now providing clues to therapeutic insights.

Recursive partitioning analysis for disease progression in adult intracranial ependymoma patients

Intracranial ependymomas are rare tumors in adults. Although recent advancements from demographic, clinical, and biological studies provide new perspectives on this rare tumor, they are not yet widely applied in clinical practice. Currently, most ependymoma patients are treated in the same way: via surgical resection with adjuvant radiation therapy. However, it is reasonable to apply more aggressive treatment for high-risk patients. From this point of view, we performed a study to investigate risk grouping for disease progression of intracranial ependymomas in adults. A total of 53 patients were included in this study. Data were extracted for patient and tumor characteristics, extent of resection, progression-free survival (PFS), and overall survival. Prognostic variables from univariate and multivariate survival analyses were included in a recursive partitioning analysis for the hierarchical risk grouping of the estimated PFS. Three risk groups were defined based on the clinical prognostic factors. Survival analysis showed significant differences in mean PFS between the different groups: 160.5±22.1months in the complete resection group, 100.4±36.8months in the incomplete-resection and intraventricular-location group, and 23.5±6.9months in the incomplete-resection and extraventricular-location group (p<0.001). The risk of disease progression in adult intracranial ependymoma patients could be stratified by degree of resection and tumor location. In clinical practice, this result could provide useful information, such as when "second-look" surgery should be performed or whether small tumors invading the fourth ventricle floor should be resected at the expense of neurological deficit.

Recent Advances in the Classification and Treatment of Ependymomas

OPINION STATEMENT

Ependymomas are a subgroup of ependymal glia-derived neoplasms that affect children as well as adults. Arising within any CNS compartment, symptoms at presentation can range from acute onset due to increased intracranial pressure to insidious myelopathy. The overall survival (OS) outcomes in adult patients across the subgroups is heterogeneous with subependymoma having an excellent prognosis often even in the absence of any treatment, whereas supratentorial ependymomas tend to be higher grade in nature and may have an OS of 5 years despite gross total resection and adjuvant radiation. The rarity of ependymal tumors, together still only representing 1.8% of all primary CNS tumors, has been a long-standing challenge in defining optimal treatment guidelines via prospective randomized trials. Retrospective studies have supported maximal safe resection, ideally gross total resection, as the optimal treatment with adjuvant radiation therapy proffering additional tumor control. The evidence for efficacy of chemotherapy and targeted agents in adult ependymomas is minimal. Recent investigations of the molecular, genetic, and DNA methylation profiles of ependymal tumors across all age groups and CNS compartments have identified distinct oncogenic gene products as well as nine molecular subgroups correlating with similar outcomes. The 2016 World Health Organization of Tumors of the Central Nervous System update addresses some of these findings, although their clinical significance has not yet been fully validated. There are inconsistent survival outcomes in retrospective studies for ependymomas graded as II versus III, bringing into question the validity of histologic grading which is subject to high interobserver variability in part due to inconsistent application of mitotic count parameters.

Advances in Management of Pediatric Ependymomas

Ependymomas are a heterogeneous group of neuroepithelial tumors of children and adults. In pediatric cases, the standard of care has long consisted of neurosurgical resection to the greatest extent acceptable followed by adjuvant involved field irradiation. Complete macroscopic surgical resection has remained the only consistent clinical variable known to improve survival. Adjuvant chemotherapy has yet to predictably affect outcome, possibly due to the molecular heterogeneity of histologically similar tumors. The administration of chemotherapy subsequently remains limited to clinical trials. However, recent comprehensive genomic, transcriptomic, and epigenetic interrogations of ependymomas have uncovered unique molecular characteristics and subtypes that correlated with clinical features such as age, neuroanatomical location, and prognosis. These findings represent a potential paradigm shift and provide a biologic rationale for targeted therapeutic strategies and risk-adapted administration of conventional treatment modalities. In this review, we focus on intracranial WHO grade II and III ependymoma of children and discuss conventional management strategies, followed by recent biologic findings and novel therapeutics currently under investigation.

Ependymoma: a heterogeneous tumor of uncertain origin and limited therapeutic options

Ependymomas are tumors that typically occur with an age-based site preference, with adults harboring supratentorial and spinal tumors and pediatric tumors being mainly in the posterior fossa. Despite their similar histologic appearance, the prognosis varies significantly by age and tumor location, with a better prognosis in increasing age. The mainstay of treatment remains surgical excision with or without radiation therapy as the tumor biology is poorly understood and chemotherapy is generally considered to be ineffective. More recently, molecular biology data have increased our understanding of the genetic and epigenetic changes that drive these tumors, but still it will take a lot of effort to find effective chemotherapeutic regimens. Currently, we are trying to define a subset of tumors, for which radiation therapy can be avoided.

CNS and spinal tumors

Primary CNS tumors consist of a diverse group of neoplasms originating from various cell types in the CNS. Brain tumors are the most common solid malignancy in children under the age of 15 years and the second leading cause of cancer death after leukemia. The most common brain neoplasms in children differ consistently from those in older age groups. Pediatric brain tumors demonstrate distinct patterns of occurrence and biologic behavior according to sex, age, and race. This chapter highlights the imaging features of the most common tumors that affect the child's CNS (brain and spinal cord).

EphB2 activation is required for ependymoma development as well as inhibits differentiation and promotes proliferation of the transformed cell

Our intracranial implantation mouse model of ependymoma clearly demonstrates overexpression of the ephrin receptor EphB2 in Ink4a/Arf^(−/−) supratentorial embryonic neural stem cells (STeNSCs) to be essential for transformation and disease development; however the requirement for and consequence of receptor activation on transformation and neural stem cell function were not examined. We definitively illustrate the necessity for receptor activation in cellular transformation and the importance of implantation site and microenvironment in directing ependymoma development. In vitro assays of EphB2 overexpressing Ink4a/Arf^(−/−) STeNSCs showed no changes in their neural stem cell characteristics (stem cell marker expression and self-renewal) upon receptor activation, but EphB2 driven tumor cells were inhibited significantly in differentiation and exhibited increased tumorsphere formation and cellular proliferation in response to ephrin-B ligand mediated receptor activation. Additionally, we observed substantial differences in the phosphorylation state of several key proteins involved in Ras and p38 MAPK signaling when comparing EphB2 overexpressing Ink4a/Arf^(−/−) STeNSCs and tumor cells with relatively little change in total protein levels. We propose that EphB2 mediated ependymoma development is a multifactorial process requiring microenvironment directed receptor activation, resulting in changes in the phosphorylation status of key regulatory proteins, maintenance of a stem-like state and cellular proliferation.

Clinical course and progression-free survival of adult intracranial and spinal ependymoma patients

BACKGROUND

Ependymomas are rare CNS tumors. Previous studies describing the clinical course of ependymoma patients were restricted to small sample sizes, often with patients at a specific institution.

METHODS

Clinically annotated ependymoma tissue samples from 19 institutions were centrally reviewed. Patients were all adults aged 18 years or older at the time of diagnosis. Potential prognostic clinical factors identified on univariate analysis were included in a multivariate Cox proportional hazards model with backwards selection to model progression-free survival.

RESULTS

The 282 adult ependymoma patients were equally male and female with a mean age of 43 years (range, 18-80y) at diagnosis. The majority were grade II (78%) with the tumor grade for 20 cases being reclassified on central review (half to higher grade). Tumor locations were spine (46%), infratentorial (35%), and supratentorial (19%). Tumor recurrence occurred in 26% (n = 74) of patients with a median time to progression of 14 years. A multivariate Cox proportional hazards model identified supratentorial location (P < .01), grade III (anaplastic; P < .01), and subtotal resection, followed or not by radiation (P < .01), as significantly increasing risk of early progression.

CONCLUSIONS

We report findings from an ongoing, multicenter collaboration from a collection of clinically annotated adult ependymoma tumor samples demonstrating distinct predictors of progression-free survival. This unique resource provides the opportunity to better define the clinical course of ependymoma for clinical and translational studies.