[1] Abertawe Bro Morgannwg Univ, Hlth Board, Dept Colorectal Surg, Baglan, Port Talbot, Wales
[2] North Bristol NHS Trust, Dept Upper Gastrointestinal Surg, Bristol, Avon, England
[3] North Bristol NHS Trust, Dept Histopathol, Bristol, Avon, England
[4] Univ Hosp Bristol NHS Fdn Trust, Dept Colorectal Surg, Bristol, Avon, England
[5] 46 Moor Gate, Portishead BS20 7FL, England