1. Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
2. Centre for Clinical Research Sörmland, Uppsala University, Eskilstuna, Sweden
3. Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim/Levanger, Norway
4. Medical Department, Levanger Hospital, Nord-Trøndelag Hospital Trust, Levanger, Norway
5. Clinic of Gastroenterology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
6. Nykøbing Falster Hospital, University of Copenhagen, Copenhagen, Denmark
7. Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland
8. Faculty of Social Sciences, Tampere University, Tampere, Finland
9. Icelandic Cancer Registry, Icelandic Cancer Society, Reykjavik, Iceland
10. Faculty of Medicine, University of Iceland, Reykjavik, Iceland
11. Department of Public Health, University of Copenhagen, Copenhagen, Denmark
12. School of Cancer and Pharmaceutical Sciences, King’s College London, London, UK