1. Department of Gastrointestinal Surgery, St Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
2. Department of Gastrointestinal Surgery, Akershus University Hospital, Lørenskog, Norway
3. Department of Registration, Cancer Registry Norway, Oslo, Norway
4. Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway
5. Department of Surgery, Haukeland University Hospital, Bergen, Norway
6. Department of Clinical Medicine, University of Bergen, Bergen, Norway
7. Department of Gastrointestinal Surgery, Tromsø University Hospital, University of Northern Norway, Tromsø, Norway
8. Department of Gastrointestinal Surgery, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway
9. Department of Surgery, Gjøvik Hospital, Innlandet Hospital Trust, Gjøvik, Norway
10. Department of Gastrointestinal Surgery, Stavanger University Hospital, Stavanger, Norway
11. Department of Gastrointestinal Surgery, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway