[1] Sapporo Med Univ, Dept Surg Surg Oncol & Sci, Chuo Ku, South 1,West 16, Sapporo, Hokkaido 0608543, Japan
[2] Tohoku Univ, Grad Sch Med, Dept Surg, Sendai, Miyagi, Japan
[3] Hamamatsu Univ, Sch Med, Dept Surg 2, Hamamatsu, Shizuoka, Japan
[4] Osaka Gen Med Ctr, Osaka, Japan
[5] Hamamatsu Univ, Sch Med, Hamamatsu, Shizuoka, Japan
[6] Natl Canc Ctr, Ctr Canc Control & Informat Serv, Tokyo, Japan
[7] Tokyo Med & Dent Univ, Tokyo, Japan
[8] Keio Univ, Sch Med, Dept Hlth Policy & Management, Tokyo, Japan
[9] Gunma Univ, Grad Sch Med, Dept Mol Pharmacol & Oncol, Maebash, Japan
[10] Hirosaki Univ, Grad Sch Med, Dept Gastroenterol Surg, Hirosaki, Aomori, Japan
[11] St Lukes Int Univ, Tokyo, Japan
[12] Keio Univ, Law Sch, Tokyo, Japan
[13] Osaka Univ, Grad Sch Med, Dept Gastroenterol Surg, Osaka, Japan
[14] Univ Tokyo, Healthcare Qual Assessment, Tokyo, Japan
[15] Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Gastroenterol Surg, Okayama, Japan
[16] JR Sapporo Hosp, Chuo Ku, North 3,East 1, Sapporo, Hokkaido 0600033, Japan