[1] Univ Hosp N Norway, Dept Oncol, N-9038 Tromso, Norway
[2] Univ Tromso, Inst Clin Med, N-9001 Tromso, Norway
[3] Univ Tromso, Inst Community Med, N-9001 Tromso, Norway
[4] Univ Oslo, Hlth Econ Res Programme, N-0316 Oslo, Norway
[5] Ullevaal Univ Hosp, Dept Oncol, Oslo, Norway
[6] Univ Bergen, Inst Internal Med, Sect Oncol, N-5020 Bergen, Norway