The diagnosis and management of breast cancer have changed dramatically over the past two decades in response not only to new technologies but also to cultural and social aspects of the discase. Mastectomy (either radical or modified radical) was the historical mainstay of the treatment of breast cancer for decades. Although mastectomy continues to be appropriate for some patients, breast conservation has become the preferred method of treatment for many patients. Meeting the dual goal of optimum cosmesis and minimal rates of in-breast recurrences after breast-conservation therapy requires the selection and integration of appropriate diagnostic methods (including breast imaging techniques and breast biopsy techniques) its well as therapeutic methods (breast irradiation techniques, and systemic cytotoxic and hormonal therapy). To achieve optimal breast-conservation treatment, a multidisciplinary approach is neccessary. Mastectomy followed by breast reconstruction is a valuable alternative for patients who require or choose mastectomy. After tumor downstaging with induction chemotherapy, a large percentage of patients with large or locally advanced tumors will be able to undergo breast-conservation therapy Partial (levels I and II) axillary lymph node dissection remains the standard of care in the surgical management of patients with invasive breast cancer. Recently there has been intense interest in selective axillary lymph node dissection, focused mainly on the identification of patients who are likely to benefit from axillary lymph node dissection, using sentinel lymph node biopsy.