Abstract: Objective To investigate the clinical effect of Pectoralis major myocutaneous flap transfer on the prevention of breast cancer-related lymphedema after modified radical mastectomy. Methods From September 2013 to June 2014, 68 patients with breast cancer were included and divided into 2 groups, interventional group and control group. The patients in interventional group were treated with modified radical mastectomy plus Pectoralis major myocutaneous flap transfer, while the patients in control group were just received mastectomy. All the patients were followed and the upper extremity lymphedema was evaluated 0.5, 1, 3, 6, 9 months after surgery. Results According to the follow-up results, the incidence of lymphedema in interventional group was obviously lower than in control group, the difference was significant （P〈0.05）. Conclusion The Pectoralis major myocutaneous flap transfer after modified radical mastectomy can significantly reduce the chances of upper limb lymphedema, and accelerate the postoperative recovery.

Key words: Breast cancer, Pectoralis major muscleflap transfer, Upper limb lymphedema