Department of Surgery, Academic Medical Center, PO Box 22660, , 1100 DD, Amsterdam, the Netherlands. a.gerritsen@amc.nl. Department of Surgery, University Medical Center Utrecht, PO Box 85500, , 3508, GA, Utrecht, the Netherlands. a.gerritsen@amc.nl. Department of Surgery, Academic Medical Center, PO Box 22660, , 1100 DD, Amsterdam, the Netherlands. t.derooij@amc.nl. Clinical Research Unit, Academic Medical Center, PO Box 22660, 1100, DD, Amsterdam, the Netherlands. m.g.dijkgraaf@amc.nl. Department of Surgery, Academic Medical Center, PO Box 22660, , 1100 DD, Amsterdam, the Netherlands. o.r.busch@amc.nl. Department of Gastroenterology and Hepatology, Academic Medical Center, PO Box 22660, 1100, DD, Amsterdam, the Netherlands. j.j.bergman@amc.nl. Department of Surgery, Academic Medical Center, PO Box 22660, , 1100 DD, Amsterdam, the Netherlands. d.ubbink@amc.nl. Department of Surgery, Gelre Hospital, PO Box 9014, 7300, DS, Apeldoorn, the Netherlands. p.van.duijvendijk@gelre.nl. Department of Gastroenterology, Gelre Hospital, PO Box 9014, 7300, DS, Apeldoorn, the Netherlands. w.erkelens@gelre.nl. Department of Surgery, University Medical Center Utrecht, PO Box 85500, , 3508, GA, Utrecht, the Netherlands. i.q.molenaar@umcutrecht.nl. Department of Gastroenterology and Hepatology, University Medical Center Utrecht, PO Box 85500, 3508, GA, Utrecht, the Netherlands. j.f.monkelbaan@umcutrecht.nl. Department of Surgery, Canisius Wilhelmina Hospital, PO Box 9015, 6500, GS, Nijmegen, the Netherlands. crosman@cwz.nl. Department of Gastroenterology, Canisius Wilhelmina Hospital, PO Box 9015, 6500, GS, Nijmegen, the Netherlands. a.tan@cwz.nl. Department of Surgery, Hospital Gelderse Vallei, PO Box 9025, 6710, HN, Ede, the Netherlands. kruytf@zgv.nl. Department of Gastroenterology, Hospital Gelderse Vallei, PO Box 9025, 6710, HN, Ede, the Netherlands. bacd@zgv.nl. Department of Gastroenterology and Hepatology, Academic Medical Center, PO Box 22660, 1100, DD, Amsterdam, the Netherlands. e.mathus-vliegen@amc.nl. Department of Surgery, Academic Medical Center, PO Box 22660, , 1100 DD, Amsterdam, the Netherlands. m.g.besselink@amc.nl.