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Staging is the classification used to define the risk of cancer recurrence and mortality. Cancer staging is useful for assessing prognosis and defining care for individuals and for defining the changes in cancer incidence and outcome for populations. A number of classifications systems for defining the extent or "stage" of cancer are used worldwide, each with its own historical basis and purpose. Three systems are used widely in the United States: the Extent of Disease (EOD) system used by the National Cancer Institute Surveillance, Epidemiology, and End Results Program (SEER); the Summary Stage system used primarily by state cancer registries; and the Tumor, Node, Metastases (TNM) system. The EOD and Summary Stage systems are used by population registries primarily for the purpose of population cancer surveillance. These systems generally do not change over time, allowing evaluation of temporal changes in cancer incidence and presentation.
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The TNM staging system is based on the major morphologic attributes of a tumor that determine its behavior: size of the primary tumor (T), presence and extent of regional lymph node involvement (N), and presence of distant metastases (M). It includes 4 classifications: clinical, pathologic, recurrence, and autopsy. Clinical classification (cTNM) is based on evidence that is gathered before initial treatment of the primary tumor, and is used to make local/regional treatment recommendations. It includes physical examination, imaging studies (including mammography and ultrasound), and pathologic examination of the breast or other tissues as appropriate (usually needle biopsies) to establish the diagnosis of breast cancer. Pathologic classification (pTNM) includes the results of clinical staging, as modified by evidence obtained from surgery and from detailed pathologic examination of the primary tumor, lymph nodes, and distant metastases (if present). It is used to assess prognosis and to make recommendations for adjuvant treatment. Classification of a recurrent tumor (rTNM) includes all information available at the time when further treatment is needed for a tumor that has recurred after a disease-free interval. Autopsy classification (aTNM) is used for cancers discovered after the death of a patient, when the cancer was not detected prior to death.
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TNM staging is the most clinically relevant staging system and is used primarily to support clinical decision-making and for evaluation of the effectiveness of treatment. Therefore, TNM undergoes periodic revision to maintain its clinical relevance. This allows incorporation of advances in the understanding of factors affecting cancer prognosis. The TNM system is maintained and revised by the American Joint Committee on Cancer (AJCC) and the Union Interanationale de Cancer Controle (UICC). These groups empanel disease-site expert teams that recommend changes to TNM and publish TNM revisions every 6 to 8 years. The sixth edition was effective for patients diagnosed after January 1, 2003. The next revision (the seventh edition) will be published in October 2009, to be effective for cancers diagnosed on or after January 1, 2010 and is described at the end of the chapter.
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Earlier in 2000, a Breast Task Force consisting ...