Ductal Carcinoma In Situ of the Breast: Controversial Issues.

Ductal carcinoma in situ (DCIS) of the breast is a heterogeneous group of lesions with diverse malignant potential and a range of controversial treatment options. It is the most rapidly growing subgroup in the breast cancer family, with more than 36,000 new cases diagnosed in the United States during 1997. Most new cases are nonpalpable and discovered mammographically. In this overview, a variety of controversial issues are discussed, including: whether or not DCIS should be considered cancer, the fallacy of grouping lesions by their pathologic architecture, an algorithm to aid in the complex treatment-selection process, the profound importance of excision margins, and the outcome following invasive local recurrence, in terms of distant recurrence and mortality. Current approaches to DCIS are based on morphology rather than etiology. In all likelihood, genetic changes precede morphologic evidence of malignant transformation. Medicine must learn how to recognize these genetic changes, exploit them, and, in the future, prevent them.