Treatment-experienced breast cancer

Breast cancer, the second leading cause of cancer mortality among women in the U.S., following lung cancer is described and the number of treatment options for patients with breast cancer, which has been accompanied by a trend toward declining cancer mortality, is reviewed. Despite these advances in cancer therapy, many patients with early stage breast cancer eventually progress to metastatic disease. Several prognostic factors have been identified for patients with metastatic breast cancer, including tumor volume and location, comorbid conditions, response to prior therapy, and the presence of molecular tumor markers (e.g., estrogen receptors [ER] and human epidermal growth factor receptor 2 [HER2]). Metastatic breast cancer is usually incurable, and the goals of therapy are palliation of symptoms, extending survival, and improving quality of life. Options for the medical management of metastatic breast cancer include endocrine therapy, cytotoxic chemotherapy, and targeted biologic agents. Treatment guidelines developed by the National Comprehensive Cancer Network generally recommend endocrine therapy for patients with ER-positive or progesterone receptor (PR)-positive disease, for patients with bone or soft tissue metastasis, or those with asymptomatic visceral disease. Cytotoxic chemotherapy alone is usually recommended for patients with ER-negative/PR-negative disease, who have symptomatic visceral disease, or whose tumors are HER2-negative or rapidly growing. Biologic agents (e.g., trastuzumab and lapatinib) alone or in combination are recommended for patients with HER2-positive disease. Treatment options for meta-static breast cancer continue to increase as new antitumor medications enter clinical practice and controlled clinical trials evaluate the optimal combinations of established and novel medications.