Immunotherapy in Breast Cancer

Breast cancer affects 12% of women worldwide. Although advances in systemic, surgical, and radiation therapy approaches will cure a large proportion of women with breast cancer, a significant subset will experience disease relapse and die as a result of their disease. Of the three main breast cancer subtypes, triple-negative breast cancer poses a special challenge to clinicians and researchers due to its aggressive features and the paucity of targetable alterations. Recent progress in immunotherapy and novel therapeutics has transformed the treatment of this breast cancer subtype. In this chapter, we introduce the reader to the biology and classification of breast cancer and review the modern multidisciplinary approaches to management, with special emphasis on the incorporation of immunotherapy in the early-stage and metastatic settings. We also review the emerging role of immunotherapy biomarkers and other modern treatments, including monoclonal antibodies and antibody-drug conjugates.