The surgical management of breast cancer continues to evolve in an attempt to define the ideal line between therapeutic efficacy and morbidity. It is clear that breast cancer is a biologically heterogeneous group of diseases, and no single hypothesis explains its behavior. The surgical options proposed to the individual patient must draw from the experience of retrospective clinical studies and prospective randomized trials in an attempt to optimize the treatment plan. Most patients without distant disease are eligible to consider mastectomy, which can accomplish excellent local control and significantly improve survival for earlier stages of disease. However, breast conservation remains an appropriate alternative for a carefully defined subset of patients. Today, with early-stage disease, no patient need leave the operating room without a breast. Recent advances in reconstructive surgery make mastectomy with immediate reconstruction or limited resection plus axillary dissection with postoperative radiation therapy the two principal treatment choices available. Future studies will focus on the integration of other treatment modalities. Clinical research into the use of preoperative chemotherapy to downstage the disease to permit less extensive surgery is of interest. Recent application of molecular biologic techniques such as oncogene analysis, cytogenetic studies, proliferative indices, and the highly sensitive detection of distant micrometastases using monoclonal antibodies may assist in the design of innovative approaches to surgery, radiation therapy, and systemic drug treatment. These advances show great promise for improving the quality of life and the cure rate for patients with breast cancer. Today, surgical treatment options have evolved that fulfill some of the objectives outlined by Dr. James Ewing of Memorial Hospital some 50 years ago. His concerns about breast cancer remain as relevant today as they were half a century ago: "I have drawn the impression that in dealing with mammary cancer, surgery meets with more peculiar difficulties and uncertainties than with almost any other form of the disease. The anatomical types are so numerous, the variations in clinical course so wide, the paths of dissemination so free and diverse, the difficulties of determining the actual conditions so complex, and the sacrifice of tissues so great, as to render impossible in the majority of cases a reasonably accurate adjustment of a means to an end."