Anti-HER2/neu Therapy in DCIS

Ductal carcinoma in situ (DCIS) is a heterogeneous form of preinvasive breast cancer, with subtypes that are comparable to those of invasive disease. Targeted molecular therapies have improved outcomes for patients with invasive breast cancer, and we have parallel opportunities for advances in personalized treatment of DCIS. Early work has demonstrated synergy between human epidermal growth factor receptor (HER)2-targeted therapy and radiotherapy. Anti-HER2 therapy may also induce an immune response. This chapter addresses the history of research regarding HER2 expression in DCIS as well as ongoing clinical trials that address whether HER2-targeted therapy will improve patient outcomes in DCIS.