The process of determining whether cancer has spread and, if so, how far. Although there is more than one system for staging, the TNM system provides three important pieces of information: T - referring to the size of the Tumor, N - describing how far the cancer has spread to nearby Nodes and M - showing whether the cancer has spread or Metastasized to other organs of the body. Letters or numbers after the T, N, and M provide a patient with more details about each of these factors. The TNM descriptions can also be grouped together into Stages labeled with Roman numerals. In general, the lower the number, the less the cancer has spread. The higher the number, the more serious the cancer is.