The grade of the tumor is used in place of a staging system to plan cancer treatment.
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 astrocytoma. Treatment is based on the grade of the tumor and whether it is untreated or recurrent (has come back after treatment). The grade of the tumor describes how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread.
The following grades are used:
Low-grade astrocytomas are slow-growing and rarely spread to other parts of the brain and spinal cord or other parts of the body. These include grade I (pilocytic, which form like a cyst and look almost like normal cells) and grade II (fibrillary, with cells that look long or slender like fibers) astrocytomas.
High-grade astrocytomas are fast-growing and often spread within the brain and spinal cord. These include grade III (anaplastic or malignant) and grade IV (glioblastoma, which spreads the fastest) astrocytomas.
Childhood astrocytomas may form at more than one place in the brain, but they do not usually spread to other parts of the body. Children who have neurofibromatosis type 1 are more likely to have tumors in more than one place.
Tests are done to find out how much tumor remains after surgery and to plan further treatment.
Some of the tests used to detect astrocytomas are repeated after the tumor is removed. This is to find out how much tumor remains after surgery and to plan further treatment. An MRI (magnetic resonance imaging) is done in the first 2 days after the surgery to see if there is any tumor left.