While other cancers are classified by stages, brain cancer is assigned a “grade” based on its pathologic features, or how the cells look under a microscope. The most commonly used brain cancer grading system (developed by the World Health Organization) is as follows:
- Grade I brain tumors are noncancerous or very slow-growing, and the cells look almost identical to healthy cells.
- Grade II brain tumors are cancerous yet slow-growing, and the cells look slightly abnormal when viewed under a microscope. These tumors may spread to nearby tissues, or they may come back after initial treatment.
- Grade III brain tumors are cancerous and grow faster than grade I and II tumors. The cancerous cells have significant abnormalities that show up during microscopic analysis, and they actively reproduce abnormal cells that may spread to other parts of the brain.
- Grade IV brain tumors are fast-growing and have a number of abnormal characteristics that are apparent when the cells are viewed under a microscope. These tumors often spread to other parts of the brain, and may even produce their own blood vessels to support the rapid growth. Also, they sometimes have small clusters of dead cells (necrosis) in their core.
In lieu of stages, patients with brain cancer are assigned a “functional neurological status.” This indicates how well a patient is able to participate in normal activities despite living with a brain tumor. A patient’s functional neurological status can range from zero (deceased) to 100 (normal with no signs of disease).
Although other cancers typically do not change stages, brain cancer can progress to a more advanced grade over time. It’s also worth noting that any other cancer that spreads to the brain is considered stage IV, regardless of the characteristics of the original tumor.
Brain Cancer Treatment at Moffitt Cancer Center
Moffitt Cancer Center’s Neuro-Oncology Program has the expertise necessary to treat patients with all grades or stages of brain cancer – even rare, high-grade malignancies. Our multispecialty team takes each patient’s unique situation into account when devising a treatment plan, and makes evidence-based recommendations for the therapies that have been found to be most effective for a patient’s specific grade of brain cancer.
Medically Reviewed by Dr. Michael Vogelbaum, Program Leader, Department of Neuro-Oncology.