BACKGROUND In the mammography screening era, we experience increasing incidence of non-invasive lesions of the breast, particularly the ductal carcinoma in situ (DCIS). It is the authors' goal to better understand this disorder in order to be able to tailor therapy individually for each patient and, most of all, to avoid overtreatment. METHODS The authors analyzed all cases of DCIS diagnosed within one mammography screening unit between 2007 and 2013. Medical reports as well as a detailed case conference protocol were used to gain all required data. RESULTS In a seven-year period, DCIS situ has been diagnosed 250 times in 249 women. Mostly the authors were able to obtain relevant information regarding tumor size, grade, biological characteristics, as well as surgery. This data was compared with current literature. CONCLUSIONS Participating women who screen positive constitute a large patient sample. Thus, we have a large amount of clinical and histological information available for planning and conducting studies regarding DCIS as well as invasive breast cancer.