Histopathological and cell biological factors of ductal carcinoma in situ before and after the introduction of mammographic screening

With the introduction of mammographic screening the incidence of ductal carcinoma in situ (DCIS) has increased to 10-15% of all breast cancers. The aim of this study was to investigate whether there were any morphological and cell biological differences between DCIS detected during the pre-screening (n = 39) as opposed to the screening period (n = 120). We could not demonstrate any statistically significant differences between the pre-screening and the screening period with regard to nuclear grade, presence of necrosis, the Van Nuys classification system, growth pattern, or cell biological factors (estrogen and progesterone receptors, c-erbB-2, p53, DNA ploidy status, Ki67, and Auer classes). These findings suggest that DCIS tumors detected during the two time periods have a similar malignant potential. DCIS detected during the screening period was further divided into the prevalence period versus the period thereafter, and symptomatic versus screening-detected asymptomatic cases. More cases with diffuse growth patterns were seen during the prevalence period than after the prevalence period, and screening-detected asymptomatic DCISs were more often 15 mm or smaller in diameter than DCISs detected symptomatically.