Treatment of DCIS in the USA, 1973 to 2002. Source: SEER (Surveillance, Epidemiology, and End Results). These data were compiled at the Northern California Cancer Center from Surveillance, Epidemiology, and End Results (SEER) Program http://www.seer.cancer.gov SEER*Stat Database: Incidence – SEER 9 Regs Public-Use, Nov 2004 Sub (1973–2002), National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released April 2005, based on the November 2004 submission, which is a sum of data from population-based cancer registries at nine distinct geographic sites collected for the period 1 January 1973 to 31 December 2002. The query was limited to women with non-invasive in situ breast cancer, excluding lobular carcinoma in situ. Rates were age-adjusted with US census data from 2000. Patients with any evidence of microinvasive disease would be considered by SEER to have invasive breast cancer and thus were excluded from the study. For this time interval 45,597 cases met this definition, 189 cases in 1973 and 3,335 in 2002. The distribution of patients by type of surgery or use of radiotherapy is based on the patients for whom there is a specific indication that the therapy was given or not given. The denominator for analyses of other therapies is based on the total number of patients diagnosed. The number of patients included in the calculation for 'lumpectomy' includes those who had a single surgical procedure and those who had an initial surgical procedure plus a re-excision. A few patients in the latter category might have been counted twice if the two procedures were performed in different years. XRT, radiotherapy.