%0 Journal Article %T Ductal Carcinoma In Situ: What the Pathologist Needs to Know and Why %A Anita Bane %J International Journal of Breast Cancer %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/914053 %X Ductal carcinoma in situ is a proliferation of malignant epithelial cells confined to the ductolobular system of the breast. It is considered a pre-cursor lesion for invasive breast cancer and when identified patients are treated with some combination of surgery, +/£¿ radiation therapy, and +/adjuvant tamoxifen. However, no good biomarkers exist that can predict with accuracy those cases of DCIS destined to progress to invasive disease or once treated those patients that are likely to suffer a recurrence; thus, in the era of screening mammography it seems likely that many patients with DCIS are overtreated. This paper details the parameters that should be included in a pathology report for a case of DClS with some explanations as to their importance for good clinical decision making. 1. Definition Ductal carcinoma in situ (DCIS) is defined as a proliferation of malignant epithelial cells that has not breached the myoepithelial layer of the ductolobular system. DCIS is a highly heterogeneous disease in terms of presentation, morphology, biomarker expression, underlying genetic alterations, and natural progression. It is considered a precursor lesion with a relative risk (RR) of 8¨C11 for the subsequent development of invasive carcinoma [1]. In most cases DCIS involves the breast in a unicentric segmental fashion and true multicentric disease is unusual occurring in an estimated 10% of cases. 2. Epidemiology DCIS currently comprises ~20¨C25% of all newly diagnosed breast cancers in North America up from ~5% of cases in the early 1980¡¯s [2, 3]. This large increase in incidence is largely ascribed to the introduction of screening mammography. Currently 80¨C85% of DCIS cases are detected by mammography and the remainder are detected as a palpable lump or nipple alteration/discharge [2]. Interestingly the incidence of DCIS in women >50 years of age has been in decline since 2003, a fact that may be related to the declining use of postmenopausal hormonal therapy, whereas the incidence of DCIS continues to rise for women less than age 50 [4]. In addition to the dramatic rise in the incidence of DCIS detection, the introduction of screening mammography has led to a decline in mortality rates from DCIS; the death rate from DCIS diagnosed between 1978 and 1983 (prescreening mammography) was 3.4% at 10 years as compared to 1.9% at 10 years with DCIS diagnosed between 1984 and 1989 (screening era). Additionally, the spectrum of DCIS diagnosed has changed with the use of screening with more low and intermediate grade DCIS being diagnosed while the relative proportion of %U http://www.hindawi.com/journals/ijbc/2013/914053/