1. Department of Surgery Soonchunhyang University Seoul Hospital Seoul Korea
2. Department of Surgery National Health Insurance Service Ilsan Hospital Goyang‐Si Korea
3. Department of Surgery, Asan Medical Center University of Ulsan College of Medicine Seoul Korea
4. Department of Surgery Chonbuk National University Hospital Jeonju‐Si Korea
5. Department of Biostatistics, College of Medicine Catholic University of Korea Seoul Korea
6. Breast Cancer Center National Cancer Center Goyang Korea
7. Department of Surgery Soonchunhyang University College of Medicine Bucheon Korea
8. Department of Breast‐Thyroid Surgery Dongkang Medical Center Ulsan Korea
9. Department of Surgery Ajou University, School of Medicine Suwon Korea