1. Department of Oncology and Pathology, Karolinska Institutet and Theme Cancer, Karolinska University Hospital, Stockholm, Sweden
2. Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet and Theme Cancer, Karolinska University Hospital, Stockholm, Sweden
3. Department of Oncology, Oslo University Hospital, Oslo, Norway
4. Department of Hepatic, Gastrointestinal and Paediatric Surgery, Oslo University Hospital, Oslo, Norway
5. Department of Oncology, Norrland University Hospital, Umeå, Sweden
6. Department of Gastrointestinal Surgery, St. Olavs hospital, Trondheim University Hospital, Trondheim, Norway
7. Department of Oncology, St.Olavs hospital, Trondheim University Hospital, Trondheim, Norway
8. Department of Oncology, Haukeland University Hospital, Bergen, Norway
9. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden