[1] St Thomas Hosp, Dept Surg, London SE1 7EH, England
[2] Royal Marsden Hosp, Dept Surg, London SW3 6JJ, England
[3] Kings Coll London, Div Canc Studies, London, England
[4] Karolinska Inst, Dept Mol Med & Surg, Unit Upper Gastrointestinal Res, Stockholm, Sweden