[1] Canc Registry Norway, N-0304 Oslo, Norway
[2] Telemark Hosp, Skien, Norway
[3] Univ Oslo, Inst Hlth & Soc, Dept Management & Hlth Econ, N-0316 Oslo, Norway
[4] Oslo Univ Hosp, Ruud Programmering 3D, Oslo, Norway
[5] Oslo Univ Hosp, Dept Transplantat Med, Oslo, Norway
[6] Sorlandet Hosp, Kristiansand, Norway
[7] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA