1. Department of Surgery; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
2. Department of Gastroenterology; Cancer Institute Hospital; Tokyo Japan
3. Department of Gastroenterology; The University of Tokyo; Tokyo Japan
4. Hepatobiliary and Pancreatic Oncology Division; National Cancer Center Hospital; Tokyo Japan
5. Department of Screening for Cancers of Digestive Organs; Osaka Medical Center for Cancer and Cardiovascular Diseases; Osaka Japan
6. Department of Surgery; Nara Medical University; Kashihara Japan
7. Department of Surgery and Oncology, Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
8. Graduate School of Medicine and Engineering; University of Yamanashi; Kofu Japan