Ependymoma

Definition

An ependymoma is a rare type of primary brain tumor that develops from the ependymal cells lining the ventricles of the brain and the central canal of the spinal cord. Ependymomas can be found anywhere in the brain or spine but are usually located in the main part of the brain, the cerebrum, and may spread from the brain to the spinal cord via the cerebrospinal fluid (CSF).

Description

Most brain tumors are named after the cells in which they are found, thus the name ependymoma for a tumor of ependymal cells. Ependymomas are classified as either supratentorial (located in the top part of the head) or infratentorial (located in the back of the head). In children, most ependymomas are of the infratentorial type and occur in or close to the fourth ventricle of the brain. Ependymomas may block the flow of cerebrospinal fluid out of the ventricles causing them to enlarge-a condition called hydrocephalus. Unlike other types of brain tumors, ependymomas as a rule do not spread into healthy brain tissue or outside the brain or spinal cord. As a result, it is often the case that they can be removed and cured by surgery, especially spinal cord ependymomas.

Demographics

Ependymomas are infrequent tumors, representing 2% to 8% of all brain tumors. However, ependymomas are the third most common brain tumor in childhood (5% to 10%) and are diagnosed in about 75 to 150 children each year in the United States. More than 50% of all ependymomas are diagnosed during childhood. In adults, ependymomas of the spine account for over half of all spinal tumors. The occurrence of ependymomas is equal among all races.

Causes and symptoms

As is the case for most brain tumors, the cause of ependymoma is unknown. Ependymal cells usually grow in an orderly and controlled way, but if for some reason this process is disrupted, the cells continue to divide and form a tumor. Research is being carried out to identify possible contributing factors. Little is known, but researchers have begun to make progress in the areas of genetic, hereditary, and environmental causes.

The first symptoms of any type of brain tumor are usually due to increased pressure within the skull. This may be the result of a blockage in the ventricles of the brain causing a buildup of CSF or may be induced by swelling around the tumor itself. The increased pressure can cause headaches, vomiting and visual problems. Symptoms specific to ependymomas include swelling of the optic nerve, rapid and jerky eye movements, neck pain and irritability. Seizures, fits and personality changes are also general symptoms associated with a brain tumor. About 25% of children with ependymomas have seizures. Other ependymoma symptoms depend on which area of the brain is affected.

• If located in the frontal lobe of the brain, ependymomas may cause mood swings, personality changes, and paralysis on one side of the body.

• If occurring on the temporal lobe of the brain, coordination, speech, and memory problems may result.

• If located on the parietal lobe of the brain, the condition may affect writing and related tasks.

• If located in the cerebellum, ependymomas may cause unsteady gait and problems with coordination and balance.

Diagnosis

To plan treatment, doctors need to find out as much as they can about the type, location, and size of the ependymoma. A number of diagnostic tests and examinations are scheduled. The first test is a neurological examination to evaluate any effect the tumor may have had on the nervous system. Every patient with ependymoma is usually subjected to diagnostic imaging of the spinal cord and brain. The most sensitive method available for evaluating spinal cord metastasis is spinal magnetic resonance imaging (MRI) performed with gadolinium, a contrast agent injected into the patient before the procedure. Other imaging studies-such as a CT scan-may also be performed to find the exact location and size of the ependymoma. To confirm the diagnosis, a biopsy will be perfomed and an ependymoma specimen will be examined under a microscope. Ependymomas sometimes spread from their original location through the CSF. An additional test called a myelogram may be done to check for this condition and to see if the tumor has spread to the spinal cord.

Treatment team

The primary physician will recommend one or more types of treatment based on the ependymoma diagnosis (size, location, type) and on the patient's medical history, age, and overall health. As a rule, the treatment team includes a neurosurgeon, a neurologist, a radiation oncologist and a medical oncologist.

Clinical staging, treatments, and prognosis

There is no formal staging system for ependymomas. They are divided into supratentorial and infratentorial tumors and treated accordingly. Treatment will proceed depending on a number of factors such as the patient's general health and age, the size and location of the ependymoma, and whether it has spread. Before any treatment is given for ependymoma, it will be important to reduce the pressure in the skull if this has occurred. If it is due to a buildup of CSF, a shunt may be inserted to drain off the excess fluid. Steroid drugs may also be prescribed to reduce swelling around the ependymoma.

When possible, surgery is the first form of treatment for ependymoma. The purpose of surgery is to remove as much of the tumor as possible without damaging the healthy brain tissue. However, it may not be possible to remove it entirely and follow-up treatment may be required. One approach is to prescribe repeated surgery in patients who still have ependymoma remaining after a first surgery and radiation therapy.

Radiation therapy, or the use of high-energy rays to destroy the cancer cells, is often used after surgery to destroy any remaining cancer cells. It may also be used alone to treat ependymomas that cannot be reached by surgery. Since ependymomas may spread to the spinal cord, radiation therapy is sometimes given to both the brain and spinal cord. Radiation oncologists are also using focal radiation techniques, meaning that they give a single large dose of radiation so as to kill residual cancer cells after regular radiation therapy in patients who have significant tumor tissue remaining after surgery.

Chemotherapy, or the use of anti-cancer drugs to destroy cancer cells, is another form of treatment indicated for ependymomas. It may be given alone or in conjunction with surgery and radiation therapy. Newer and improved chemotherapeutic drugs are now being used after surgery, with the goal of shrinking the ependymoma before radiation therapy.

Postoperative radiation therapy has definitely been shown to improve chances of recovery, but results of chemotherapy are considered somewhat disappointing. Age is also a factor in recovery. Usually, the younger the patient, the less favorable the prognosis. The best recoveries usually occur in patients who have no visible tumor after surgery.

Alternative and complementary therapies

In a search for less toxic therapies and improved quality of life, patients with primary brain tumors are increasingly considering complementary and alternative treatments. The American Brain Tumor Association provides a list of therapies such as acupuncture, antioxidant therapy, acupressure, meditation, etc. However, the association does not officially endorse any of them. The treatment team will be able to offer the best advice as to whether alternative and/or complementary treatments are indicated.

Coping with cancer treatment

Learning to live with ependymoma can be difficult for both patient and family. Several national associations exist to educate, support and advocate for families of children with cancer, survivors of childhood cancer, and the health professionals who care for them. These organizations offer contacts with peer-support groups and distribute a wealth of cancer-related brochures and publications.

Clinical trials

In 2001, the National Cancer Institute supported over 33 ependymoma clinical trials to evaluate a variety of new treatments. The National Cancer Institute monitors clinical trials and should be contacted for up-to-date information.

Prevention

A large, coordinated investigation recently carried out in Europe, Israel, and North America studied the factors that might affect the occurrence of primary brain tumors in infants and children under the age of 20. Conclusions were that women taking vitamin supplements containing C, A, E, and/or folate during the entire period of their pregnancy were half as likely to have their child develop a brain tumor before age 5, as compared to those who did not take vitamins.

Special concerns

Recurrence of an ependymoma is very dependent upon the extent of surgical removal as well as on the success of the treatment course following the initial diagnosis. Most recurrent ependymomas occur in the vicinity of the cavity from which the original tumor was surgically removed. Treatment options for an individual with a recurrent ependymoma usually include more surgery, chemotherapy, and further radiotherapy. An ependymoma can also metastasize into adjacent areas of the brain or, less commonly, to distant parts of the central nervous system. Approximately 12% of patients will have evidence of metastasis at the time of diagnosis. In these situations, more extensive treatment is used to treat the disease.

Children diagnosed with ependymomas are the object of special concern because of their vulnerability to radiation therapy. The organs in children are, generally speaking, significantly more sensitive to radiation than those of adults. Thus, radiation doses delivered to a child may have devastating side effects and must therefore be designed so as to address the issues of toxicity as well as that of treatment efficiency.

When the ependymoma causes blockage of CSF flow and leads to hydrocephalus, a special tubing called a ventriculo-peritoneal shunt (VP shunt) can be surgically implanted in the brain ventricles to drain the excess CSF into the abdomen. This procedure allows the fluid to bypass the tumor blockage and relieves the pain and symptoms of hydrocephalus.

KEY TERMS

Brain

One of the two parts of the central nervous system (CNS). It is responsible for the control of body activities and the interpretation of information obtained from the senses. The brain is the center of thoughts and emotions.

Brain ventricles

Four connected hollow cavities in the brain.

Central nervous system (CNS)

In humans, the CNS consists of the brain, cranial nerves, and spinal cord.

Cerebrospinal fluid (CSF)

A clear, colorless fluid that fills the ventricles of the brain and contains small quantities of glucose and proteins. It bathes the brain and spinal cord.

Cerebellum

Part of the brain responsible for somatic motor function, the control of muscle tone and maintenance of balance.

Cerebrum

Part of the brain where thought and higher functions reside.

Ependymal cells

These cells line the ventricles within the central part of the brain, and thus form part of the pathway through which cerebrospinal fluid travels.

Frontal lobe

Part of the brain responsible for higher thought processes.

Metatastis

The transfer of cancer from one location or organ to another one not directly related to it.

Metatastic brain cancer

Tumors that start in other organs and then spread to the brain.

Primary brain cancer

Cancers that start in the brain.

Parietal lobe

One of two brain hemispheres responsible for associative processes.

Spinal cord

Elongated part of the central nervous system of vertebrates that lies in the vertebral canal and from which the spinal nerves emerge.

Temporal lobe

Part of the brain located below the cerebrum and responsible for auditory (hearing) and receptive processes.

QUESTIONS TO ASK THE DOCTOR
• Where is the ependymoma located?

• What is the next step? Are more tests necessary

• What kinds of specialists should I seek out for treatment?

• What medication is necessary, and what is it for? What are the side-effects?

• Considering age and the extent of the ependymoma, what is the current prognosis?