Because tumors in the brain or spinal cord almost never spread to other parts of the body, there is no formal staging system for them. Some of the most important factors that help determine outlook include:
Tumor Grading System
- Functional Level (whether the tumor has started to interfere with normal brain functions)
- Tumor Type and Tumor Grade (how quickly the tumor is likely to grow)
- Size and Location
- Whether the tumor can be removed by surgery.
- Whether cancer cells remain after surgery.
- Whether there are certain changes in the chromosomes.
- Whether tumor cells have spread beyond the central nervous system
- Whether the tumor has spread through the cerebrospinal fluid (CSF) to other parts of the brain and/or spinal cord.
Brain and spinal cord tumors are named based on the type of cell they formed in and where the tumor first formed in the central nervous system. The grade of a tumor may be used to tell the difference between slow- and fast-growing types of the tumor and is based on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread.
- Grade I (low-grade) — The tumor grows slowly, has cells that look a lot like normal cells, and rarely spreads into nearby tissues. It may be possible to remove the entire tumor by surgery.
- Grade II — The tumor grows slowly, but may spread into nearby tissue and may recur (come back). Some tumors may become a higher-grade tumor.
- Grade III — The tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.
- Grade IV (high-grade) — The tumor grows and spreads very quickly and the cells do not look like normal cells. There may be areas of dead cells in the tumor. Grade IV brain tumors are harder to cure than lower-grade tumors.