Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. ntaira@md.okayama-u.ac.jp. Clinical Research Promotion Center, University of Tokyo Hospital, Tokyo, Japan. Advanced Cancer Translational Research Institute, Showa University, Tokyo, Japan. Breast Disease Center, Asahikawa Medical University Hospital, Hokkaido, Japan. Department of Breast Surgery, National Hospital Organization Hokkaido Cancer Center, Hokkaido, Japan. Department of Breast Surgery, Teine Keijinkai Hospital, Hokkaido, Japan. Department of Breast Surgery, Kansai Medical University Hospital, Osaka, Japan. Department of Breast Surgery, Niigata City General Hospital, Niigata, Japan. Department of Medical Oncology, National Cancer Center Hospital East, Chiba, Japan. Department of Breast Surgery, Hirosaki Municipal Hospital, Aomori, Japan. Department of Breast Surgery, Japanese Red Cross Saitama Hospital, Saitama, Japan. Department of Medical Oncology, Faculty of Medicine, Kindai University, Osaka, Japan. Department of Breast and Endocrine Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan. Breast Center, Aihara Hospital, Osaka, Japan. Breast Oncology Center, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan.