1. From the Institut Gustave Roussy, Villejuif; Service of Biostatistics; and Lyon-Sud Hospital, Lyon-Sud, Pierre-Bénite; Val-d'Aurel Center, Montpellier; L'Archet Hospital, Nice; Paul Papin Institute, Angers; and French Association of Surgery, Paris, France; Jolimont Hospital, Haine-St Paul, Belgium; and Maisonneuve-Rosemont Hospital, Montréal, Canada.