As of 2015, there is no standardized staging system for brain tumors since this type of malignancy rarely metastasize or spread outside the central nervous system, states the American Society of Clinical Oncology. Instead of a staging system, a grading system is used for brain cancer.Continue Reading
Grading defines the similarities in appearance between cancerous and healthy cells when observed under a microscope. It also indicates the rate of growth of the malignant cells.
The grading system for brain tumors, established by the World Health Organization, is divided into four types: grade I, grade II, grade III and grade IV, according to the American Brain Tumor Association. The highest grade, which is grade IV, is assigned to the most malignant and the fastest growing brain tumors. These cancerous cells are characterized by formation of new blood vessels to sustain their rapid proliferation.Learn more about Cancer