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Staging is a way of describing the size of a tumor, where it is located, if it is cancerous or where it has spread, and whether it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the tumor's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
Medulloblastoma in children is classified as either standard (average) risk or high risk, depending on the following factors: the child's age, how much of the tumor remains after surgery, and whether the tumor has spread.
Standard-risk tumor. The tumor is almost completely removed during surgery, meaning that less than 1.5 cubic centimeters of the tumor remains after surgery. The tumor is in the very back part of the brain and has not spread to other areas of the brain and spinal cord.
High-risk tumor. This type of tumor has either spread to other parts of the brain or the spine, or it has not spread but more than 1.5 cubic centimeters of tumor remains after surgery.
Recurrent tumor. A recurrent tumor is a tumor that comes back after treatment. It may recur in the brain, spine, spinal fluid or very rarely elsewhere in the body. If there is a recurrence, the tumor may need to be staged again (called re-staging) using the system above.