Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand. Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, Hong Kong. Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, Hong Kong. laujyw@surgery.cuhk.edu.hk. Department of Surgery, Prince of Wales Hospital, Room 64026, Lui Chee Woo Clinical Science Building, 32 Ngan Shing Street, Shatin, NT, Hong Kong SAR, China. laujyw@surgery.cuhk.edu.hk.