1. Department of Oncology, Oslo University Hospital, Ullevål, Norway
2. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
3. General Practice Research Unit (AFE), Department of General Practice, Institute of Health and Society, University of Oslo, Oslo, Norway
4. Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
5. Institute of Clinical Medicine, Faculty of Health Services, UiT The Arctic University of Norway, Oslo, Norway