Changes to Adjuvant Systemic Therapy in Breast Cancer: A Decade in Review

Breast cancer is the second most common cause of cancer death in women among the United States. Fortunately, it continues to be an active area of research. Today, it is well recognized that breast cancer can often be a systemic disease, with micrometastatic involvement at diagnosis in many patients. Over the past decade, adjuvant systemic therapy has been used to eradicate micrometastatic disease, and it has been shown to decrease the rates of recurrence and improve the survival of patients with early-stage, resected breast cancer. Some of the success of modern adjuvant systemic therapy has come from the advent of new chemotherapy and endocrine agents but also from the development of targeted therapies, which have improved the efficacy of conventional, cytotoxic therapy. There has also been increasing awareness that the dosing and schedule of administration of systemic therapies are equally important factors in achieving better outcomes in patients with early-stage breast cancer. Growing research into the biology and genomics of breast cancer has fueled the development of more accurate risk stratification tools and helped individualize the decision to recommend adjuvant systemic therapy. Herein, we present a review of salient developments over the past decade that have helped shape the adjuvant systemic therapy of today.