Staging is a way of describing where the tumor is located, if 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 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 tumors.
There is no formal staging system for ependymoma, however, it can be classified based on where in the brain the tumor is located and whether it has spread.
Supratentorial: The tumor is above the membrane that covers the cerebellum, known as the tentorium cerebella.
Infratentorial: The tumor is growing below the tentorium cerebella.
Spinal: The tumor is growing in the central canal of the spinal cord.
Recurrent: A recurrent tumor is a tumor that comes back after treatment. If there is a recurrence, the tumor may need to be staged again (called re-staging) using the system above.
A tumor may also be described by its grade, which is used to describe how much the tumor appears like normal tissue when viewed with a microscope. In a tumor that resembles normal tissue, doctors can clearly see different types of cells grouped together (called well differentiated). In a higher-grade tumor, the cells usually look less like normal cells, or “wilder” (called poorly differentiated or undifferentiated). In general, a child with a more differentiated, lower-grade tumor has a better prognosis.