Division of Breast Surgery, Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. Department of Rehabilitation Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. Division of Breast Surgery, Department of Surgery, Ulsan University Hospital, Ulsan, Korea. Department of Surgery, Inje University Ilsan Paik Hospital, Goyang-si, Gyeonggi-do, Korea. Division of Breast Surgery, Department of Surgery, Dongnam institute of Radiological and medical science, Busan, Korea. Division of Breast Surgery, Department of Surgery, Kosin University Gospel Hospital, Busan, Korea. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, Seoul, Korea.