1 Department of Hepato Pancreato Biliary Surgery, Oslo University Hospital, Oslo 0372, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: k.j.labori@medisin.uio.no.
2 Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Surgery, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
3 Department of Oncology, Oslo University Hospital, Oslo, Norway.
4 Department of Hepato Pancreato Biliary Surgery, Oslo University Hospital, Oslo 0372, Norway; Institute of Clinical Medicine, the Arctic University of Norway, Tromsø, Norway.