1 University of Oslo and Oslo University Hospital, Oslo, Norway and Harvard School of Public Health, Boston, Massachusetts.
2 Centre of Postgraduate Medical Education and The Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
3 University Medical Center Rotterdam, Rotterdam, the Netherlands.
4 Kaiser Permanente, Oakland, California.
5 University of Oslo and Oslo University Hospital, Oslo, Norway and Frontier Science Foundation, Boston, Massachusetts.
6 University of Oslo, Oslo, Norway and Centre of Postgraduate Medical Education and Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.