[1] Univ Cattolica Sacro Cuore, Digest Endoscopy Unit, I-00168 Rome, Italy
[2] Univ Hosp Geneva, Div Gastroenterol & Hepatol, Geneva, Switzerland
[3] Maria Sklodowska Curie Mem Canc Ctr, Dept Gastroenterol, Warsaw, Poland
[4] Med Ctr Postgrad Educ, Warsaw, Poland
[5] Oporto Oncol Inst, Dept Gastroenterol, Oporto, Portugal
[6] Cochin Hosp, Dept Gastroenterol, Paris, France
[7] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol & Hepatol, NL-1105 AZ Amsterdam, Netherlands
[8] Med Univ Vienna, Dept Internal Med 3, Div Gastroenterol & Hepatol, Vienna, Austria
[9] Hosp Gen Univ Alicante, Dept Gastroenterol, Alicante, Spain
[10] Telemark Hosp, Dept Clin Res, Skien, Norway
[11] Univ Oslo, Dept Hlth Management & Hlth Econ, Inst Hlth & Soc, Oslo, Norway
[12] Oslo Univ Hosp, Div Canc Med Surg & Transplantat, Oslo, Norway
[13] Ruhr Univ Bochum, Dept Med, Knappschaftskrankenhaus, Bochum, Germany
[14] Gen Infirm, Ctr Digest Dis, Leeds LS1 3EX, W Yorkshire, England
[15] Oregon Hlth & Sci Univ, Portland, OR 97201 USA