Brain Cancer Staging

Updated: Oct 15, 2019
  • Author: Jeffrey N Bruce, MD; Chief Editor: Herbert H Engelhard, III, MD, PhD, FACS, FAANS  more...
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Grading of Brain Tumors

The widely used tumor-node-metastasis (TNM) classification system was found to be inappropriate for brain tumors, as tumor size is less relevant than tumor histology and location, the brain has no lymphatics, and most of these patients die before developing metastatic disease. Instead, the histologic classification employed by the World Health Organization (WHO) for central nervous system (CNS) tumors, shown below, makes use of 4 grades. [1, 2]

WHO histologic grading for CNS tumors (glioma)

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 oligodendroglioma, anaplastic oligoastrocytoma

Grade IV:

  • Lesions that are mitotically active, necrosis-prone, and generally associated with a rapid preoperative and postoperative evolution of disease

  • Glioblastoma, gliosarcoma