Ependymoma: Evaluation and Management Updates

PURPOSE OF REVIEW

To review state of art and relevant advances in the molecular genetics and management of ependymomas of children and adults.

RECENT FINDINGS

Ependymomas may occur either in the brain or in the spinal cord. Compared with intracranial ependymomas, spinal ependymomas are less frequent and exhibit a better prognosis. The new WHO classification of CNS tumors of 2021 has subdivided ependymomas into different histomolecular subgroups with different outcome. The majority of studies have shown a major impact of extent of resection; thus, a complete resection must be performed, whenever possible, at first surgery or at reoperation. Conformal radiotherapy is recommended for grade 3 or incompletely resected grade II tumors. Proton therapy is increasingly employed especially in children to reduce the risk of neurocognitive and endocrine sequelae. Craniospinal irradiation is reserved for metastatic disease. Chemotherapy is not useful as primary treatment and is commonly employed as salvage treatment for patients failing surgery and radiotherapy. Standard treatments are still the mainstay of treatment: the discovery of new druggable pathways will hopefully increase the therapeutic armamentarium in the near future.

Chemotherapy for adult patients with spinal cord gliomas

Background

The incidence of spinal cord gliomas, particularly in adults is low, and the role of chemotherapy has remained unclear.

Methods

We performed a multicenter, retrospective study of 21 patients diagnosed with spinal cord glioma who received chemotherapy at any time during the disease course. Benefit from chemotherapy was estimated by magnetic resonance imaging. Data on radiotherapy were taken into consideration.

Results

Thirteen patients were diagnosed with astrocytic gliomas World Health Organization (WHO) grades 1-4, the remaining eight patients with ependymomas WHO grades 1 or 3. Most patients had more than one neurosurgical intervention. Median age at time of first chemotherapy was 33 years (range 21-67 years). Seven patients had chemotherapy combined with radiotherapy as first-line treatment. Two patients had chemoradiotherapy at recurrence, without prior tumor-specific treatment beyond surgery. One patient received chemotherapy alone as first-line treatment and 2 patients had chemotherapy alone at recurrence, without prior treatment. Nine patients had received radiation therapy at an earlier time and chemotherapy was given at time of further recurrences. Best responses in astrocytomas were as follows: chemotherapy alone-2 stable disease (SD) and 3 progressive disease (PD); chemoradiotherapy-1 complete response, 3 SD, and 4 PD. Best responses in ependymomas were as follows: chemotherapy alone-1 partial response, 5 SD, and 1 PD; chemoradiotherapy-1 SD.

Conclusions

Spinal cord gliomas represent a heterogeneous group of tumors. Survival outcomes in response to chemotherapy in adult spinal cord glioma patients vary substantially, but individual patients appear to derive benefit from chemotherapy.

Intracranial ependymomas: The role of advanced neuroimaging in diagnosis and management

Intracranial ependymomas represent a rare subgroup of glial tumours, showing a wide variety of imaging characteristics, often representing a challenging diagnosis for neuroradiologists. Here, we review the most recent scientific Literature on intracranial ependymomas, highlighting the most characteristic computed tomography and magnetic resonance imaging features of these neoplasms, along with epidemiologic data, recent classification aspects, clinical presentation and conventional therapeutic strategies. In addition, we report an illustrative case of an 18-year-old girl presenting with an intracranial supratentorial, anaplastic ependymoma, with the aim of contributing to the existing knowledge and comprehension of this rare tumour.

Ependymomas overexpress chemoresistance and DNA repair-related proteins

BACKGROUND

After surgery and radiation, treatment options for ependymoma are few making recurrence a challenging issue. Specifically, the efficacy of chemotherapy at recurrence is limited. We performed molecular profiling on a cohort of ependymoma cases in order to uncover therapeutic targets and to elucidate the molecular mechanisms contributing to treatment resistance.

RESULTS

This ependymoma cohort showed minimal alterations in gene amplifications and mutations but had high expression rates of DNA synthesis and repair enzymes such as RRM1 (47%), ERCC1 (48%), TOPO1 (62%) and class III β-tublin (TUBB3) (57%), which are also all associated with chemoresistance. This cohort also had high expression rates of transporter proteins that mediate multi-drug resistance including BCRP (71%) and MRP1 (43%). Subgroup analyses showed that cranial ependymomas expressed the DNA synthesis enzyme TS significantly more frequently than spinal lesions did (57% versus 15%; p = 0.0328) and that increased TS expression was correlated with increased tumor grade (p = 0.0009). High-grade lesions were also significantly associated with elevated expression of TOP2A (p = 0.0092) and TUBB3 (p = 0.0157).

MATERIALS AND METHODS

We reviewed the characteristics of 41 ependymomas (21 cranial, 20 spinal; 8 grade I, 11 grade II, 22 grade III) that underwent multiplatform profiling with immunohistochemistry, next-generation sequencing, and in situ hybridization.

CONCLUSIONS

Ependymomas are enriched with proteins involved in chemoresistance and in DNA synthesis and repair, which is consistent with the meager clinical effectiveness of conventional systemic therapy in ependymoma. Adjuvant therapies that combine conventional chemotherapy with the inhibition of chemoresistance-related proteins may represent a novel treatment paradigm for this difficult disease.

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.

Biology and management of ependymomas

Ependymomas are rare primary tumors of the central nervous system in children and adults that comprise histologically similar but genetically distinct subgroups. The tumor biology is typically more associated with the site of origin rather than being age-specific. Genetically distinct subgroups have been identified by genomic studies based on locations in classic grade II and III ependymomas. They are supratentorial ependymomas with C11orf95-RELA fusion or YAP1 fusion, infratentorial ependymomas with or without a hypermethylated phenotype (CIMP), and spinal cord ependymomas. Myxopapillary ependymomas and subependymomas have different biology than ependymomas with typical WHO grade II or III histology. Surgery and radiotherapy are the mainstays of treatment, while the role of chemotherapy has not yet been established. An in-depth understanding of tumor biology, developing reliable animal models that accurately reflect tumor molecule features, and high throughput drug screening are essential for developing new therapies. Collaborative efforts between scientists, physicians, and advocacy groups will enhance the translation of laboratory findings into clinical trials. Improvements in disease control underscore the need to incorporate assessment and management of patients' symptoms to ensure that treatment advances translate into improvement in quality of life.

[Chemotherapy of brain tumors in aduts]

The treatment of patients with brain tumors has long been the domain of neurosurgery and radiotherapy but chemotherapy is now well established as an additional treatment option for many tumor entities in neuro-oncology. This is particularly true for patients with newly diagnosed and relapsing glioblastoma and anaplastic glioma as well as the treatment of medulloblastoma and primary lymphoma of the central nervous system (CNS). In addition to purely histopathological features, treatment decisions including those for chemotherapy are now based increasingly more on molecular tumor profiling. Within the group of gliomas these markers include the methylation status of the O-6-methylguanine-DNA methyltransferase (MGMT) promoter and the 1p/19q status, which reflects the loss of genetic material on chromosome arms 1p and 19q. The presence of a 1p/19q codeletion is associated with a better prognosis and increased sensitivity to alkylating chemotherapy in patients with anaplastic gliomas.