Treatment of breast cancer.

Understanding breast cancer treatment options can help family physicians care for their patients during and after cancer treatment. This article reviews typical treatments based on stage, histology, and biomarkers. Lobular carcinoma in situ does not require treatment. Ductal carcinoma in situ can progress to invasive cancer and is treated with breast-conserving surgery and radiation therapy without further lymph node exploration or systemic therapy. Stages I and II breast cancers are usually treated with breast-conserving surgery and radiation therapy. Radiation therapy following breast-conserving surgery decreases mortality and recurrence. Sentinel lymph node biopsy is considered for most breast cancers with clinically negative axillary lymph nodes, and it does not have the adverse effects of arm swelling and pain that are associated with axillary lymph node dissection. Choice of adjuvant systemic therapy depends on lymph node involvement, hormone receptor status, ERBB2 (formerly HER2 or HER2/neu) overexpression, and patient age and menopausal status. In general, node-positive breast cancer is treated systemically with chemotherapy, endocrine therapy (for hormone receptor-positive cancer), and trastuzumab (for cancer overexpressing ERBB2). Anthracycline- and taxane-containing chemotherapeutic regimens are active against breast cancer. Stage III breast cancer typically requires induction chemotherapy to downsize the tumor to facilitate breast-conserving surgery. Inflammatory breast cancer, although considered stage III, is aggressive and requires induction chemotherapy followed by mastectomy, rather than breastconserving surgery, as well as axillary lymph node dissection and chest wall radiation. Prognosis is poor in women with recurrent or metastatic (stage IV) breast cancer, and treatment options must balance benefits in length of life and reduced pain against harms from treatment.