1. Guy's & St Thomas' NHS Foundation Trust Guys and St Thomas’ Oesophago-Gastric Centre, , London, UK
2. University of Southampton Faculty of Medicine, School of Cancer Sciences, , Southampton, UK
3. CHU de Montpellier Service de Chirurgie Digestive A Pôle Digestif, , Montpellier, France
4. University Hospitals Birmingham Department of Bariatric Surgery, , Birmingham, UK
5. Karolinska University Hospital Department of Molecular Medicine and Surgery, Karolinska Institutet, , Stockholm, Sweden
6. University of Oxford Nuffield Department of Surgery, , Oxford, UK
7. University of Bristol Population Health Sciences, , Bristol, UK
8. Division of Surgery , Head and Neck, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
9. Upper Gastrointestinal Surgery Department, Musgrove Park Hospital , Taunton, UK