Ependymoma tumors are the third most common form of brain cancer in children and the most common form of pediatric spinal cord tumor, accounting for approximately 9% or all pediatric brain cancer diagnoses. These tumors can occur at any age, but appear most often in young children around age 3. While the primary cause of ependymoma is unknown, children with Neurofibromatosis-Type 2 (NF2) may have an increased risk of developing these tumors. NF2 is an inherited condition that, in general, increases the risk of developing tumors of the brain and central nervous system.
Ependymomas initially form in the ependymal cells (a type of glial cell) in the brain and spinal cord. Ependymal cells line the ventricles (passageways) through which cerebrospinal fluid (CSF) flows. While most ependymomas remain in the location where they first form, between 5-10% will spread (metastasize) to other parts of the brain or spinal cord. Very rarely, these cancer cells will spread to other parts of the body. According to the American Society of Clinical Oncology, the 5-year survival rate for children aged 0-19 with ependymoma in the U.S. is roughly 77%.
Most commonly, childhood ependymomas occur in the posterior fossa, which is an area located in the lower back portion of the brain and encompassing the cerebellum. These tumors can also appear in the area just above the cerebellum (the supratentorial brain), and in the spinal cord.
Ependymomas that grow in the ventricles of the brain can block the flow of CSF, causing the unaffected ventricles surrounding the affected area to swell and build up fluid. This is called obstructive hydrocephalus, and can most commonly cause headaches and severe vomiting. Children may also experience double or blurred vision, or increased pressure in the skull causing them to hold their heads in a tilted position. In addition, children may experience challenges with hearing, speech, swallowing, balance, or mobility.
Ependymomas that grow along the spinal cord can cause pain and/or weakness in the arms or legs, depending on the exact location of the tumor, and can also cause a child to appear to have scoliosis.
The first line of treatment for ependymoma brain tumors is typically surgical removal, with the goal of removing 100% of the tumor (known as a gross total resection). If a total resection is successful, a child may not need any further treatment. However, if the ependymoma tumor is located in an area of the brain or spine that is especially sensitive, total surgical removal may be too risky. If fragments of the tumor remain, of if the tumor is totally inoperable, additional treatment may be required.
Many children with ependymomas undergo post-surgery radiation therapy to the area in which the tumor was located. Radiation therapy uses high-energy beams such as x-rays or protons to kill any remaining tumor cells. If tumor cells have not spread, radiation therapy is directed exclusively at the site of the tumor. However, if the ependymoma cells have spread to other areas, radiation therapy for the whole brain or spine may be recommended.
In many cases, chemotherapy drug treatment is not observed to be particularly effective for treating ependymoma patients. However, it may be beneficial if used in combination with other treatment options, such as in an attempt to shrink a tumor prior to surgical removal, for patients with high-grade tumors, or for patients whose tumors cannot be surgically removed. A number of clinical trials are currently underway to identify the best possible drug treatment options for children.
Ependymoma Research at CBTTC
The Children’s Brain Tumor Tissue Consortium (CBTTC)’s Pediatric Brain Tumor Atlas (PBTA) has harmonized and annotated over 33 TB of data from tumor and normal tissue collected from 88 CBTTC ependymoma study participants, including aligned/unaligned reads, Histology Imaging, Radiology Reports/Imaging, Operation Reports, Pathology Reports, and gVCFs. In addition, the CBTTC’s biorepository – which hosts the largest collection of pediatric brain cancer biosamples on earth – currently holds over 2,000 samples of tumor/normal tissue, blood, saliva, CSF, Plasma, DNA/RNA, and more from ependymoma patients experiencing an initial diagnosis, recurrence, or progression of their brain or spinal tumor.
A number of ependymoma biospecimen and data projects conducted by CBTTC collaborating investigators are currently underway.
CBTTC’s ependymoma research projects seek to better understand the biology, molecular mechanisms, and genetic precursors of these pediatric brain/spinal cord tumors, including those to improve the identification and classification of tumor sub-types and genomic alterations in malignant supernatorial tumors, with the goal of developing a better understanding of the relationship between genetically determined tumor subtypes and clinical factors including histology, tumor location, metastatic status, and survival.
Studies to advance immunotherapies for ependymomas include those examining the microenvironment of an ependymoma tumor as it relates to tumor progression, toward identifying new potential immunotherapy targets.
The CBTTC continues to advance the sharing of data and resources across the biomedical research landscape by partnering with other consortia and national data initiatives, including the PEDSNET Clinical Data Research Network, wherein both entities are working to harmonize longitudinal health data to better annotate the complex biology collected from cancer patients – specifically children suffering from rare high-grade gliomas including ependymoma.
Partners in the CBTTC’s ependymoma research efforts also include the CBTTC Advisory Council, The Children’s Brain Tumor Foundation, Alex’s Lemonade Stand Foundation, and the Council on Library and Information Resources (CLIR), among many others.
- CBTTC Biospecimen Project 03e: Advancing Collaborative Pediatric Brain Tumor Research Through Temporally-based Predictive Modeling of a Large-scale National Clinical Data Research Network
- CBTTC Biospecimen Project 05: Exploration of IDO1 as a Therapeutic Target in pCNS Tumors
- CBTTC Biospecimen Project 08: Developing a Novel Tumor Model to Screen for New Therapies for Spinal Ependymoma
- CBTTC Data Project 19: Molecular Analysis of the Cellular Ecosystem of Childhood Ependymoma
- CBTTC Biospecimen Project 25: Development of Preclinical Models of Pediatric Ependymoma
- CBTTC Data Project 37: Comprehensive Genomic and Immune Signature Profiling of Ependymoma and Diffuse Intrinsic Pontine Glioma
*Background information and statistics regarding Pediatric Ependymomas were provided by:
The Mayo Clinic, OncoLink, The American Society of Clinical Oncology, and The Collaborative Ependymoma Research Network