1 Department of Gastroenterological Surgery, Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
2 Department of Gastroenterological Surgery, Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan. naoki.hiki@jfcr.or.jp.
3 Department of Upper Gastrointestinal Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan. naoki.hiki@jfcr.or.jp.