1 Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
2 Center of Excellence for Innovation and Endoscopy in Gastrointestinal Oncology, Chulalongkorn University, Bangkok, Thailand.
3 Division of Gastroenterology and Hepatology, San Francisco Veterans Affairs Medical Center, San Francisco, California, USA.
4 Department of Surgery, Rajavithi Hospital, Bangkok, Thailand.