A new method of modified radical mastectomy for breast cancer.

We have developed a new type of modified radical mastectomy, the method and clinical results of which are reported herein. In this operation, axillary dissection is performed by the following two approaches. Firstly, the axillary contents are dissected from the highest possible subclavicular point to the pectoralis minor muscle, after partially cutting the sternocostal origin of the pectoralis major muscle. The second approach is from the posterior aspect of the pectoralis minor muscle to the lateral portion of the latissimus dorsi muscle. Parasternal dissection can also be performed for stage II and IIIa cancers with a central or medial tumor. After lymph node dissection, the detached edge of the sternocostal origin of the pectoralis major muscle is resutured to cover the parasternal region. Thus, complete dissection of the axillary nodes is performed whilst preserving the pectoralis major and pectoralis minor muscles. Good clinical results were achieved with respect to radicality, cosmetic effects and function in 28 patients with stage I, II, and IIIa breast cancers who were followed up for between 5 to 8 years. This new operation may therefore be adopted for the majority of patients with Stage I, II, or IIIa cancers, unless massive infiltration into the pectoralis major muscle has occurred. Preservation of both the pectoralis major and pectoralis minor muscles results in a good cosmetic appearance, good functioning of the arm and easy reconstruction of the breast following mastectomy.