There are no generally useful staging systems for most brain tumors, although some are classified according to grade. With brain stem glioma, for example, tumors in the higher region—the mid-brain—are more likely to be lower grade and have a higher chance of long-term survival than tumors lower down in the pons and the medulla (40 percent versus less than 20 percent).
A variety of staging systems have been used for medulloblastoma. The Pediatric Oncology Group and the Children's Cancer Group have divided this tumor into low and high stages. Essentially, low-stage implies smaller tumors without metastasis , in which the tumor remaining after surgery is smaller than 1.5 cubic cm. High-stage refers to larger tumors with evidence of metastatic spread or brain stem involvement and tumor over 1.5 cubic cm remaining after surgery.
