Staging for cancer. New developments and importance to pathology.

Important to both the physician and patient, cancer staging is an agreed upon classification for defining the extent of a malignant tumor. The present staging system is based principally on the anatomic spread of the primary tumor beyond three landmarks. The first landmark is the site of the primary tumor, usually referred to as topography, the second landmark is the regional lymph nodes or adjacent anatomic structures, and the third landmark refers to distant metastases. These three landmarks define the topographic, lymph node, and metastatic system of staging that has been promulgated by the International Union Against Cancer and the American Joint Committee on Cancer in the United States. Staging systems have been developed for all anatomic sites including pediatric tumors. In many cases, the key physician, in providing the necessary information for accurate staging, is the pathologist.