Objective   To explore matters related to prognosis and treatment of accessory breast cancer using breast-conserving surgery.

  Methods   Retrospective analysis was carried out on the clinical data of 23 patients who underwent two different modes of surgery and were admitted to Tianjin Medical University Cancer Institute and Hospital and Dagang Oil Field Hospital from September 2003 to July 2013.

  Results   No sign of accessory breast cancer was shown by clinical examination, mammography, and ultrasonography of the breast in all 10 cases of surgery without breast removal. Three patients underwent postoperative radiotherapy, and all three showed radiodermatitis in different degrees. Follow-up results revealed that two out of the ten patients who underwent surgery without breast removal had bone metastasis, whereas one of the other 13 had pulmonary metastasis. All patients are still alive as of October 2013.

  Conclusion   Accessory breast cancer treatment without ipsilateral breast removal is viable if no sign of the disease is evident in the breast, and possible signs of radiodermatitis can be expected.