[1] Peterborough City Hosp, Dept Gen Surg, Peterborough, Cambs, England
[2] Univ Cambridge, Addenbrookes Hosp, Dept Oncol, Cambridge Canc Trials Ctr, Cambridge CB2 2QQ, England
[3] Univ Forvie Site, MRC Biostat Unit Hub Trials Methodol Res, Cambridge, England
[4] Peterborough City Hosp, Dept Oncol, Peterborough, Cambs, England
[5] Cambridge Univ Hosp NHS Fdn Trust, Addenbrookes Hosp, Dept Oncol, Cambridge, England