1. Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
2. Statistics and Data Management Center, NRG Oncology, American College of Radiology, Philadelphia, Pennsylvania
3. Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada
4. Department of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas
5. Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York
6. Department of Medicine Head and Neck Service, Memorial Sloan Kettering Cancer Center, New York, New York
7. Department of Clinical Oncology, Chinese University of Hong Kong, Shatin, Hong Kong
8. Department of Radiation Oncology, New York University Langone Medical Center, New York, New York
9. Accrual for State University of New York Health Science Center, Brooklyn, New York
10. Department of Medicine, Stanford University, Stanford, California
11. Accruals for University of California, San Francisco
12. Department of Radiation Oncology, McGill University, Montreal, Quebec, Canada
13. Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania
14. Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison
15. Helen F. Graham Cancer Center, Christiana Care Health System, Newark, Delaware
16. Department of Radiation Oncology, Stanford University, Stanford, California