1. From the Memorial Sloan-Kettering Cancer Center, New York, NY; the Radiation Therapy Oncology Group Statistical Office; the University of Pennsylvania, Philadelphia, PA; Mayo Clinic Cancer Center, Scottsdale, AZ; Washington University, St Louis, MO; the University of Kansas, Lawrence, KS; The University of Texas M.D. Anderson Cancer Center, Houston, TX; Duke University, Durham, NC; and the University of Western Ontario, London, Ontario, Canada