An Overview of the History and Epidemiology of Ductal Carcinoma In Situ of the Breast

Abstract: Since the first pathologic studies of breast cancer were undertaken in the nineteenth century, an intraepithelial stage has been recognized in the transition from normal tissue to invasive cancer. In 1932 this was labeled in situ breast carcinoma, but was rarely diagnosed and considered only a clinical oddity. With the establishment of screening mammography over the past 20 years, both the ductal and lobular types of in situ breast carcinoma have been increasingly diagnosed. The lobular variant, lobular carcinoma in situ (LCIS), is now considered a marker of risk for subsequent invasive cancer, and is managed expectantly without surgical ablation. The ductal form, ductal carcinoma in situ (DCIS), is considered a true premalignant lesion, which should be treated largely in the same way as invasive breast carcinoma. An understanding of the epidemiology and biologic implications of DCIS is necessary for a rational approach to treatment.