[1] Univ Bristol, Sch Social & Community Med, 39 Whatley Rd, Bristol BS8 2PS, Avon, England
[2] Severn Sch Surg, Deanery House,Unit D,Vantage Off Pk, Bristol BS16 1GW, Avon, England
[3] Royal Victoria Infirm, Northern Oesophago Gastr Unit, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England
[4] Velindre Hosp, Dept Oncol, Cardiff CF14 2TL, S Glam, Wales
[5] Univ Hosp Bristol NHS Fdn Trust, Bristol BS2 8HW, Avon, England