Management of Lobular Neoplasia and Ductal Carcinoma in Situ

Although traditionally thought to be an invasive cancer precursor, lobular carcinoma in situ (LCIS) is now considered a high-risk benign lesion with lifetime invasive cancer risk 8 to 10 times that seen among women without LCIS. When diagnosed on core needle biopsy, current guidelines recommend consideration of diagnostic surgical excision for discordant pathology/imaging findings, pleomorphic LCIS, and/or when associated with other atypical findings to rule out missed malignancy. Observation alone can be offered to individuals with classic LCIS on core biopsy deemed concordant with imaging. Aggressive surgical resection of all disease at a surgical margin, even at the time of lumpectomy for a concurrent invasive tumor, is not advocated. Ductal carcinoma in situ (DCIS) is a heterogeneous group of lesions with diverse malignant potential and a range of treatment options. Approximately 60,000 new cases are diagnosed in the United States yearly with more than 90% of newly diagnosed DCIS being discovered mammographically. It is now well appreciated that DCIS is a stage in the neoplastic continuum in which most biological alterations required for the development of invasive breast cancer are already present. As our understanding of lobular neoplasia and DCIS has evolved, so has their treatment. Clinical research has focused on the identification of prognostic and biologic factors that strongly influence treatment selection, while new surgical and radiologic techniques have developed to accommodate these new therapy options. This chapter reviews each of these subjects to provide the reader with a workable framework on which to evaluate patient-specific lobular neoplasia and DCIS treatment decisions..