Breast cancer is a global health problem and the most common cancer in both the developed and developing world. The lifetime probability of developing breast cancer is one in six overall (one in eight for invasive disease). It is a heterogeneous, phenotypically diverse disease composed of several biologic subtypes that have distinct behaviors and responses to therapy.
The use of adjuvant systemic therapy is responsible, at least in part, for the reduction in cause-specific mortality from breast cancer seen in almost every Western nation . Whether tumors are estrogen (ER) or progesterone (PR) receptor positive or negative, the choice of agents used as adjuvant chemotherapy (ie, the administration of cytotoxic treatment following primary surgery) is the same. Treatment directed against the human epidermal growth factor receptor 2 (HER2) is incorporated for those patients with HER2 overexpression. (See "Adjuvant medical therapy for HER2-positive breast cancer".)
This topic will discuss the role of chemotherapy in the adjuvant treatment of early stage breast cancer, how to estimate the benefit and risk of chemotherapy, the indications for adjuvant chemotherapy, and the dosing and timing of treatment. Adjuvant medical therapy for patients with early stage HER2-positive breast cancer, adjuvant endocrine therapy, the treatment of male breast cancer, and breast cancer in older patients are discussed separately:
Other topics related to the topic of breast cancer are also discussed elsewhere. (See "Overview of the treatment of newly diagnosed, non-metastatic breast cancer".)