1 Clinical Effectiveness Research Group, Department of Transplantation Medicine, Oslo University Hospital, and Clinical Effectiveness Research Group, University of Oslo, Oslo, Norway.
2 Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, United Kingdom.
3 National Cancer Institute, Division of Cancer Prevention, Rockville, Maryland.
4 University Hospital Città della Salute e della Scienza, Turin, Italy.