[1] Haukeland Hosp, Dept Oncol, N-5021 Bergen, Norway
[2] EORTC Headquarters, Dept Stat, Brussels, Belgium
[3] Ctr Hosp Univ Ambroise Pare, Assistance Publ Hop Paris, Dept Surg, Boulogne, France
[4] Ctr Hosp Univ Ambroise Pare, Assistance Publ Hop Paris, Dept Oncol, Boulogne, France