Cancer data consist of one record per incident breast malignancy as coded by western Washington State’s Surveillance Epidemiology and End Results registry (SEER). Breast cancer data are available from SEER back to 1977. In 2004, the American Joint Committee on Cancer (AJCC), SEER, and the American College of Surgeons (ACoS) created collaborative staging guidelines to address the discrepancies in staging between the three major organizations in the cancer registry field. The new guidelines provide more information about the extent of the primary tumor as well as the extent of metastasis and distant lymph node involvement. For more information, please see the documentation of collaborative staging for details.
