After the childhood supratentorial primitive neuroectodermal tumor or pineoblastoma has been removed, tests are done to find out if there is tumor remaining.

The extent or spread of cancer is usually described as stages. For childhood supratentorial primitive neuroectodermal tumors and pineoblastoma, risk groups are used instead of stages. Risk groups are described by the amount of remaining tumor or spread of cancer cells within the central nervous system (brain and spinal cord) or to other parts of the body. It is important to know the risk group in order to plan treatment. The following tests and procedures may be used in determining the risk group:

• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the brain and spinal cord. A substance called gadolinium is injected into the patient through a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Lumbar puncture: A procedure used to collect cerebrospinal fluid from the spinal column. This is done by placing a needle into the spinal column. A pathologist views the fluid under a microscope to look for cancer cells. This procedure is also called an LP or spinal tap.
• 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.
• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

The following risk categories are used for childhood supratentorial primitive neuroectodermal tumors and pineoblastoma:

Average risk

Childhood supratentorial primitive neuroectodermal tumors and pineoblastoma are called average risk if all of the following are true:

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

Poor risk

Childhood supratentorial primitive neuroectodermal tumors and pineoblastoma are called poor risk if any of the following are true:

• The child is younger than 3 years.
• The tumor is near the center of the brain.
• Some of the tumor was not removed by surgery.
• The cancer has spread to other parts of the brain or body, including the spinal cord.

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