1. Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston
2. Program on Regulation, Therapeutics, and Law (PORTAL), Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
3. Department of Medicine, Harvard Medical School, Boston, Massachusetts
4. Department of Gastrointestinal Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston
5. Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston