Division of Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. The Children's Oncology Group, Monrovia, California. Division of Biostatistics, University of Southern California, Los Angeles, California. Division of Oncology, Children's Hospital of Eastern Ontario, Ottawa, Ontario. Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Division of Oncology, AI Dupont, Wilmington, Delaware. Division of Oncology, Seattle Children's Hospital, Seattle, Washington. Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario.