[1] Univ Hosp North Tees, Tees Bowel Canc Screening Ctr, Stockton On Tees TS19 8PE, England
[2] North Tyneside Gen Hosp, Dept Gastroenterol, North Shields, Tyne & Wear, England
[3] Princess Alexandra Hosp, Dept Gastroenterol, Harlow, Essex, England
[4] Univ Hosp North Tees, Dept Gastroenterol, Stockton On Tees TS19 8PE, England