1. Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas
2. Department of Radiation Oncology, Brigham and Women’s Hospital, Boston, Massachusetts
3. Dana-Farber Cancer Institute/Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
4. Division of Biostatistics, Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas
5. Department of Medical Oncology, University of Texas Southwestern Medical Center, Dallas
6. Dana-Farber Cancer Institute McGraw/Patterson Center for Population Sciences, Boston, Massachusetts