Treatment is based on the child’s risk group.

Staging is the process used to find out how much cancer there is and if cancer has spread. It is important to know the stage in order to plan treatment.

There is no standard staging system for childhood central nervous system (CNS) embryonal tumors. Instead, treatment depends on the child’s risk group:

Average risk

Childhood CNS embryonal tumors are called average risk when all of the following are true:

• The child is older than 3 years of age.
• All of the tumor was removed by surgery or there was only a very small amount remaining.
• The cancer has not spread to other parts of the body.

High risk

Childhood CNS embryonal tumors are called high risk if any of the following are true:

• The child is 3 years of age or younger.
• Some of the tumor was not removed by surgery.
• The cancer has spread to other parts of the body.

In general, cancer is more likely to recur (come back) in patients in the high-risk group.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The information from tests and procedures done to detect (find) childhood CNS embryonal tumors is used to plan cancer treatment.

Some of the tests used to detect childhood CNS embryonal tumors are repeated after the tumor is removed by surgery. (See the General Information section.) This is to find out how much tumor remains after surgery. Other tests and procedures may be done to find out if the cancer has spread:

• Lumbar puncture : A procedure used to collect cerebrospinal fluid from the spinal column. This is done by placing a needle into the spinal column. This procedure is also called an LP or spinal tap.

• Bone marrow aspiration and biopsy : The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow, blood, and bone under a microscope to look for signs of cancer.
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  Bone marrow aspiration and biopsy. After a small area of skin is numbed, a Jamshidi needle (a long, hollow needle) is inserted into the patient’s hip bone. Samples of blood, bone, and bone marrow are removed for examination under a microscope.

• Bone scan : A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.