1. Department of Research, Cancer Registry of Norway, 0304 Oslo, Norway
2. Department of Interdisciplinary Health Science, Institute of Health and Society, University of Oslo, 0318 Oslo, Norway
3. Department of Infection Control and Vaccine, Norwegian Institute of Public Health, 0213 Oslo, Norway
4. School of Cancer and Pharmaceutical Sciences, King’s College London, London WC2R 2LS, UK