1. aDepartment of Radiation Oncology, and
2. bDivision of Biostatistics, Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas;
3. cDepartment of Statistical Science, Southern Methodist University, Dallas, Texas;
4. dDepartment of Clinical Sciences, and
5. eHarold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas; and
6. fDepartment of Radiation Oncology, Dana-Farber/Brigham and Women’s Hospital, and
7. gMcGraw/Patterson Center for Population Sciences, Dana-Farber Cancer Institute, Boston, Massachusetts.