1 Department of Surgery, University Surgical Cluster, National University Hospital, Singapore.
2 Division of General Surgery (Upper Gastrointestinal Surgery), University Surgical Cluster, National University Hospital, Singapore; Division of Surgical Oncology (Upper Gastrointestinal Surgery), National University Cancer Institute, Singapore.
3 Division of General Surgery (Upper Gastrointestinal Surgery), University Surgical Cluster, National University Hospital, Singapore; Division of Surgical Oncology (Upper Gastrointestinal Surgery), National University Cancer Institute, Singapore; Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: [email protected].