Cancer Staging

Cancer staging is the process of describing the extent of cancer within the body and determining whether the cancer has spread (and if so, how far). Staging systems differ depending upon the type of cancer. The TNM staging system, which is used most often, gives your doctors three key pieces of information:

T refers to the size of the tumor.
N describes whether the cancer has spread to nearby lymph nodes, and if so, how many
M shows whether the cancer has spread (metastasized) to other organs of the body.

Letters or numbers after the T, N, and M give more details about each of these factors. To make this information clearer, the TNM descriptions can be grouped together into a simpler set of stages, labeled with Roman numerals (usually from I to IV). In general, the lower the number, the less the cancer has spread. A higher number means a more serious cancer.

The two main types of staging are clinical and pathologic.

• Clinical staging is an estimate of the extent of cancer based on physical exam, biopsy results, and imaging tests.
• Pathologic staging is an estimate of the extent of cancer by studying the tissue removed during surgery.