1. Clinical Effectiveness Unit, The Royal College of Surgeons of England, London, United Kingdom
2. Department of Gastroenterology, St. Mary’s Hospital, London, United Kingdom
3. Department of Surgery, Addenbrookes Hospital, Cambridge, United Kingdom
4. Department of Gastroenterology, Northern General Hospital, Sheffield, United Kingdom
5. Velindre Cancer Centre, Cardiff, Wales, United Kingdom
6. Department of Surgery and Cancer, St. Mary’s Hospital, London, United Kingdom