[1] Natl Canc Ctr, Natl Canc Control Res Inst, Div Canc Registration & Biostat, Goyang 410769, South Korea
[2] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Surg, Seoul 138736, South Korea
[3] Natl Canc Ctr, Korea Cent Canc Registry, Goyang, South Korea
[4] Yonsei Univ, Yongdong Severance Hosp, Coll Med, Dept Surg, Seoul 120749, South Korea
[5] Ctr Breast Canc, Goyang, South Korea
[6] Korean Breast Canc Society, Seoul, South Korea