1 Division of Hepatobiliary and Pancreatic Surgery, Cancer Institute Hospital for Japanese Foundation for Cancer Research, Tokyo, Japan. Electronic address: hiromichi.ito@jfcr.or.jp.
2 Division of Hepatobiliary and Pancreatic Surgery, Cancer Institute Hospital for Japanese Foundation for Cancer Research, Tokyo, Japan.
3 Department of Hepatobiliary-Pancreatic Surgery, Juntendo University School of Medicine, Tokyo, Japan.