1. Division of Gastroenterology and Gastrointestinal Endoscopy, IRCCS San Raffaele Scientific Institute, Vita-Salute San Raffaele University, 20132 Milan, Italy
2. Department of Gastrointestinal Surgery, IRCCS San Raffaele Scientific Institute, Vita-Salute San Raffaele University, 20132 Milan, Italy
3. Department of Gastroenterology and Digestive Endoscopy, San Camillo-Forlanini Hospital, 00152 Rome, Italy
4. Department of Surgery, Cancer Center Amsterdam, 1081 HV Amsterdam, The Netherlands