Brain Tumor, Childhood

Childhood brain tumors are a diverse group of diseases characterized by the abnormal growth of tissue contained within the skull. Brain tumors can be benign (without cancer cells) or malignant (contains cancer cells). The brain controls vital functions such as memory and learning, the senses (hearing, sight, smell, taste, and touch), and emotion. It also controls other parts of the body, including muscles, organs, and blood vessels. Other than leukemia and lymphoma, brain tumors are the most common type of cancer that occurs in children.

This summary refers only to tumors that originate in the brain (primary brain tumors). Metastatic brain tumors, which are secondary tumors formed by cancer cells that begin in other parts of the body and spread to the brain, are not included. Brain tumors can occur in both children and adults; however, treatment may be different for adults than for children.

If your child has symptoms that may be caused by a brain tumor, his or her doctor may order a computed tomographic (CT) scan, a diagnostic test that uses computers and x-rays to create pictures of the body. A magnetic resonance imaging (MRI) scan, a diagnostic test similar to a CT scan but which uses magnetic waves instead of x-rays, may also be performed.

Often, surgery is required to determine whether a brain tumor exists and what type of tumor it is. A small sample of tumor tissue may be surgically removed and examined under a microscope. This is called a biopsy. Sometimes a biopsy is done by making a small hole in the skull and using a needle to extract a sample of the tumor.

There are many types of brain tumors that occur in children. Treatment and chance of recovery (prognosis) depend on the type of tumor, its location within the brain, the extent to which it has spread, and your child’s age and general health.

Types of childhood brain tumor

Once childhood brain tumor is detected, additional tests will be performed to determine the type of tumor. If a biopsy specimen is taken, the tumor cells will be examined carefully under a microscope to see how different they appear from normal cells. This will determine the grade of the tumor. The grade of a tumor is determined by microscopic examination of its cells to see how similar the cells are to normal cells. Cells from higher-grade, more abnormal-looking tumors usually grow faster and are more malignant than cells from lower-grade tumors. Your child’s doctor needs to know the type and grade of tumor in order to plan treatment.

There is no staging for childhood brain tumors. Brain tumors are grouped according to their location within the brain and the appearance and behavior of the tumor tissue. The following groupings are used for childhood brain tumors:

INFRATENTORIAL TUMORS

Infratentorial tumors are those that occur in the lower part of the brain. Tumors found in this region include:

• Medulloblastoma
• Cerebellar Astrocytoma

Infratentorial ependymoma

Ependymal tumors are tumors that begin in the ependyma, the cells that line the hollow cavities within the brain (called ventricles) which are filled with cerebrospinal fluid). The growth of ependymal tumors can obstruct the flow of the cerebrospinal fluid through the brain and spinal cord. Infratentorial ependymomas begin in the lower part of the brain. These tumors may spread via the cerebrospinal fluid to other areas of the brain and spinal cord.

Brain stem glioma 

SUPRATENTORIAL TUNMORS

Supratentorial tumors are those that occur in the upper part of the brain. Common supratentorial tumors include:

Cerebral Astrocytoma

Supratentorial ependymoma

Ependymal tumors are tumors that begin in the ependyma, the cells that line the hollow cavities within the brain (called ventricles) which are filled with cerebrospinal fluid. The growth of ependymal tumors can obstruct the flow of the cerebrospinal fluid through the brain. Supratentorial ependymomas begin in the upper part of the brain. These tumors may spread to other areas of the brain and spinal cord, depending on their grade.

Craniopharyngioma

Craniopharyngiomas are tumors that generally occur just above the pituitary gland. Located at the bottom of the brain, the pituitary gland is about the size of a pea and controls many vital functions. Craniopharyngiomas do not spread, but may interfere with important structures near them, causing serious problems.

Central nervous system germ cell tumor

Germ cell tumors arise from the sex cells found in the brain. There are different types of germ cell tumors, including germinomas, embryonal cell carcinomas, choriocarcinomas, and teratomas. These tumors usually occur in the center of the brain, and can spread to other parts of the brain and spinal cord.

Supratentorial primitive neuroectodermal tumors and pineoblastoma

Visual pathway and hypothalamic glioma 

Spinal Cord Tumors

Spinal cord tumors are rare benign or cancerous tumors in the spinal cord (the bundles of nerves that carry messages between the brain and the body). The diagnosis of spinal cord tumors depends on how the tumor looks under a microscope and its location. Spinal cord tumors compress the spinal cord and the surrounding nerves causing symptoms such as pain or numbness in the back, arms, or legs, decreased muscle strength, and in some cases, loss of bowel or bladder control. X-rays of the brain and the entire spine are done at the time of diagnosis to determine extent of disease.

Treatment Option Overview

There are treatments for all children with brain tumors. Three kinds of treatment are used:

• Surgery (removing the tumor in an operation)
• Radiation therapy (using high-dose x-rays to kill tumor cells)
• Chemotherapy (using drugs to kill tumor cells)

More than one method of treatment may be used, depending on the needs of the patient.

Experienced doctors working together may provide the best treatment for children with brain tumors. Your child’s treatment will often be coordinated by a pediatric oncologist, a doctor who specializes in cancer in children. The pediatric oncologist may refer your child to other specialists, such as a pediatric neurosurgeon (a specialist in childhood brain surgery), a pediatric neurologist, a psychologist, a radiation oncologist, and other doctors who specialize in the type of treatment your child requires.

Treatment options often depend on the type of tumor and its location within the brain. Complete or near complete removal of the tumor is often possible. If the tumor cannot be completely removed, radiation therapy and/or chemotherapy may also be given.

Radiation therapy uses high-energy radiation from x-rays and other sources to kill cancer cells and shrink tumors. Radiation therapy for childhood brain tumors usually comes from a machine outside the body (external radiation therapy). For some types of brain tumors, clinical trials are evaluating radiation therapy given in several small doses per day (hyperfractionated radiation therapy). Since radiation therapy can affect growth and brain development, other clinical trials are testing ways to decrease or delay radiation therapy, especially for younger children who have not yet achieved full growth.

Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy drugs may be taken by mouth or injected into a vein (intravenous) or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells throughout the body. Chemotherapy is being studied in clinical trials as a means of delaying, modifying or eliminating the need for radiation therapy in younger patients, as well as for use prior to or during radiation therapy.

Treatment for recurrent disease depends on the type of tumor, whether the tumor recurs in the site in which it originated or elsewhere, the amount of time between initial treatment and the recurrence, and the type of treatment previously given.

Recurrent low-grade glial tumors

Treatment options consist of surgery, radiation therapy, and chemotherapy. Clinical trials are currently evaluating the role of chemotherapy for treatment of these tumors.

Recurrent infratentorial ependymomas

Treatment options include surgery and chemotherapy. Clinical trials are currently evaluating the role of chemotherapy for treatment of these tumors.

Recurrent supratentorial ependymoma

Treatment usually consists of chemotherapy. Clinical trials are currently evaluating the role of chemotherapy for treatment of these tumors.

Recurrent central nervous system germ cell tumors

Treatment usually consists of chemotherapy. Clinical trials are currently evaluating the role of chemotherapy for treatment of these tumors.

Source:  National Cancer Institute