1 From the Department of Clinical and Experimental Medicine, Faculty of Health and Medical Sciences, University of Surrey, and the HPB Surgical Unit, Royal Surrey NHS Foundation Trust, Guildford, and the Department of Surgery and Cancer, Imperial College London, London (A.E.F.), and the Department of Oncology, University of Oxford, and the Department of Oncology, Oxford University Hospitals NHS Foundation Trust, Oxford (S.S.) - all in the United Kingdom.