Recent aggressive changes in the strategy for breast cancer treatment have reduced the frequency of mastectomy as the primary surgery. In addition to the current expanded indications for breast-conserving therapy (BCT), the introduction of preoperative chemotherapy for patients with operable tumors allows BCT to be performed in a larger population of patients. The results of a questionnaire on breast cancer surgery conducted in Japan in 2000 revealed that the frequency of radical modified mastectomy had decreased by 52.2%. However, mastectomy cannot be completely eliminated, since some patients still present with locally advanced tumors and preoperative chemotherapy cannot remove the requirement for mastectomy in all patients. The current standard procedure for mastectomy appears to be the Auchincloss operation. The Halsted radical mastectomy is performed only for patients with cancer involving the pectoralis major muscle or the chest wall, and/or with marked axillary lymph node metastasis and Rotter's node metastasis. Simple mastectomy is selected for wide-spread noninvasive cancer and recently in our department for patients confirmed to be node negative by preoperative sentinely lymph node biopsy. In dealing with the changes in the treatment algorithm, we need to select the appropriate surgical options flexibly.