1. Department of Oncology, Akershus University Hospital, Lørenskog, Norway
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway
3. Department of Research, Sørlandet Hospital, Kristiansand, Norway
4. Academic Unit of Surgery, School of Medicine Dentistry and Nursing, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
5. Department of Surgery, Elizabeth University Hospital, Glasgow, UK