Brain tumor staging
Brain tumor Microchapters |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Staging is a way of describing a tumor, such as where it is located, if or where it has spread, and whether it is affecting the functions of other organs in the body. A staging system is used for most other types of cancer. There is a formal staging system for adult brain tumors; however, the grading system described below is always used instead.
After a brain tumor has been diagnosed, additional tests will be done to learn more about the tumor. If the tumor is a glial brain tumor, the pathologist will assign a “grade” using a number from I to IV (one to four). The grade indicates how different the tumor cells are from healthy cells, with a higher grade tumor having cells that are the least like healthy cells. The characteristics of the tumor, as seen under the microscope, help determine how cancerous a tumor is. Generally, the lower the grade, the better the prognosis (chance of recovery or long-term control of the tumor).
WHO histologic grading for CNS tumors:
Grade I:
- Lesions with low proliferative potential, a frequently discrete nature, and the possibility of cure following surgical resection alone
- Juvenile pilocytic astrocytoma, subependymal giant cell astrocytoma
Grade II:
- Lesions that are generally infiltrating and low in mitotic activity but recur; some tumor types tend to progress to higher grades of malignancy
- Diffuse astrocytoma, oligodendroglioma, oligoastrocytoma
Grade III:
- Lesions with histologic evidence of malignancy, generally in the form of mitotic activity, clearly expressed infiltrative capabilities, and anaplasia
- Anaplastic astrocytoma, anaplastic oligoastrocytoma, anaplastic oligoastrocytoma
Grade IV:
- Lesions that are mitotically active, necrosis-prone, and generally associated with a rapid preoperative and postoperative evolution of disease
- Glioblastoma