1The Pelican Cancer Foundation, The Ark, Basingstoke, Hampshire, UK2Department of Colorectal and Peritoneal Malignancy Surgery, Hampshire Hospitals NHS Foundation Trust, Basingstoke, Hampshire, UK3Department of Clinical Statistics, Imperial College London, London, UK4Department of Surgery, Aarhus University Hospital, Aarhus, Denmark5Radiotherapy Department, Mount-Vernon Cancer Centre, Mount-Vernon Hospital, Northwood, UK6Department of Colorectal Surgery, Salisbury NHS Foundation Trust, Salisbury, Wiltshire, UK