 Airway management in anesthesia is critical to guarantee appropriate treatment of possible respiratory complications and successful operative practice. LMA is an alternative to tracheal tube in some surgeries like as mastectomy on breast cancer. Given no need using muscular relaxants in mastectomy, the investigators hypothesized that LMA would be a superior manner in airway management in radical modified mastectomy on breast cancer than the tracheal tube, and the LMA might produce less influence on patients circulatory homeostasis, and easier to be placed before operation. 