[1] Department of Surgery, Catharina Hospital, Postbox 1350, ZA Eindhoven
[2] Department of Surgery, Leiden University Medical Centre, Leiden
[3] Department of Radiology, Oxford University Hospitals NHS Foundation Trust
[4] CRUK MRC Oxford Institute for Radiation Oncology, Oxford University Hospitals NHS Foundation Trust
[5] Department of Colorectal Surgery, Oxford University Hospitals NHS Foundation Trust