[1] Sunnybrook Reg Canc Ctr, Toronto, ON, Canada
[2] Royal Marsden Hosp, Dept Med, Sutton, Surrey, England
[3] Peter MacCallum Canc Inst, Melbourne, Vic 3000, Australia
[4] HELIOS, Klinikum Berlin, Charite, Robert Rossle Klin, Berlin, Germany
[5] Hosp Marques Valdecilla, SV Oncol Med, Santander, Spain
[6] Ist Nazl Tumori, Div Med Oncol Unit 2, I-20133 Milan, Italy
[7] Dept Stat, Paris, France
[8] F Hoffmann La Roche & Co Ltd, CH-4002 Basel, Switzerland
[9] Univ Hosp Gasthuisberg, Digest Oncol Unit, B-3000 Louvain, Belgium