Cancer and Ependymomas

Being diagnosed with an ependymoma can evoke a sense of fear, shock, and even anger. For many patients, the next question is, “Is it cancer?” While all ependymomas do have the potential to become cancerous, only certain types of ependymomas are more likely to be cancerous.

Read on to learn more about the distinction between benign and malignant (cancerous) tumors, and which ependymoma subtypes are more cancerous than others.

An ependymoma is a type of brain or spinal cord tumor that arises from ependymal cells lining the ventricles or central canal of the spinal cord. Ependymomas are relatively rare, accounting for about 2% to 3% of all adult primary brain tumors. These tumors can occur in individuals of any age. Ependymomas of the brain are more commonly found in children and young adults, whereas ependymomas of the spine are more commonly found in adults. 

Like most tumors, an ependymoma can become cancerous, but finding this type of tumor is not necessarily a cancer diagnosis. Ependymomas are categorized into different subtypes and grades based on their location, appearance under the microscope, and molecular features. A higher grade is associated with more rapid growth rates and likelihood of spreading to other parts of the body.

There are 3 different grades of ependymomas based on the World Health Organization (WHO) classification system:

• The only ependymoma subtype that can be considered Grade 1 is a subependymoma
• These tumors are slow-growing and well-differentiated, meaning they look similar to normal ependymal cells
• They tend to be located near the ventricles and are usually non-cancerous (benign)

• Subtypes that may be Grade 2 include myxopapillary ependymoma, spinal ependymoma, posterior fossa ependymoma, and supratentorial ependymoma
• They are typically more aggressive than Grade 1 tumors and may grow and spread to nearby tissues
• Grade 2 ependymomas can be either benign or malignant and tend to have a higher risk of recurrence

• Subtypes that may be Grade 3 include spinal ependymoma, posterior fossa ependymoma, and supratentorial ependymoma
• These tumors are the most aggressive type of ependymoma and are more likely to spread to other parts of the brain or spinal cord
• Grade 3 ependymomas are malignant and have a poorer prognosis than the lower grade tumors

The difference between benign and malignant ependymomas is based on their behavior and characteristics. Although the grade of an ependymoma provides information that can help to predict whether a tumor is benign or malignant, this can be difficult in the case of a Grade 2 tumor with features that are in-between that of a benign and malignant tumor. 

In general, benign and malignant ependymomas differ as follows:

• Grade 1 ependymomas (subependymoma)
• Typically grow slowly and are well-differentiated (closely resemble normal tissue)
• Tend to stay localized in the area where they originated
• Generally have a good prognosis with a high likelihood of complete removal by surgery
• May not require further treatment after surgical removal

• Grade 3 ependymomas (spinal ependymoma, posterior fossa ependymoma, and supratentorial ependymoma)
• Tend to grow more quickly and may invade nearby tissues or spread to other parts of the brain or spinal cord
• Can be poorly differentiated (look less like normal tissue) and have abnormal genetic features
• Have a higher chance of recurrence after treatment and may require additional surgery, radiation therapy, and/or chemotherapy
• Prognosis for malignant ependymomas depend on several factors, including tumor grade, location, size, as well as the patient’s age and overall health

Grade 2 ependymomas have features in-between that of a benign and malignant tumor, making their aggressiveness more difficult to predict. For example, myxopapillary ependymomas are Grade 2 ependymomas that are associated with positive survival outcomes, but typically recur after treatment.

Spinal ependymomas and most brain ependymomas are Grade 2 or 3, meaning that they are more likely to be cancerous. The exact grading will be determined by your pathologist and is based on additional microscopic and molecular features. Knowing both the ependymoma subtype and the associated grade for your tumor will be important to predict the aggressiveness of the tumor.

Ependymomas are diagnosed through a combination of imaging tests and tissue biopsy. A biopsy, which removes a small portion of the tumor for further evaluation, can confirm the ependymoma subtype and determine whether a particular ependymoma is cancerous.

Treatment for a cancerous ependymoma can be a long journey. Surgery is typically the mainstay of treatment because complete removal of the tumor is often the best way to achieve long-term control. Radiation therapy and chemotherapy may be used to destroy any remaining cancer cells or treat ependymomas that have spread to other parts of the brain or spinal cord.

Aggressive ependymomas may recur and multiple treatments may be required. The choice and duration of treatment are unique to each ependymoma and will be decided by a multidisciplinary team of healthcare professionals. It will be important for you to understand the risks and benefits of treatment, attend all appointments, and communicate regularly with your healthcare team to ensure that treatment aligns with your health goals.

• Most ependymomas are cancerous.
• Grade 1 ependymomas are benign, and Grade 3 tumors are malignant.
• Grade 2 ependymomas may have both benign and malignant features, making their behavior more difficult to predict.
• A biopsy is an important diagnostic tool for determining whether an ependymoma is malignant or benign. 
• Cancerous ependymomas are generally treated with a combination of surgery, radiation therapy, and chemotherapy.

• Collaborative Ependymoma Research Network (CERN)
• American Brain Tumor Association (ABTA)
• The Childhood Brain Tumor Foundation
• Pediatric Brain Tumor Foundation