1. Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center–Arthur G. James Cancer Hospital, Columbus, Ohio
2. NRG Oncology Statistics and Data Management Center, Philadelphia, Pennsylvania
3. The Ohio State University Center for Biostatistics, Columbus, Ohio
4. National Institutes of Health, Bethesda, Maryland
5. University of Maryland Medical Systems, Baltimore, Maryland (during trial)6now with Miami Cancer Institute, Coral Gables, Florida
6. University of Calgary, Calgary, Alberta, Canada
7. Moffitt Cancer Center, Tampa, Florida
8. University of Alabama, Birmingham, Alabama
9. Utrecht Cancer Center, Utrecht, Netherlands
10. University of Freiburg, Freiburg, Germany
11. University Hospital Zurich, Zürich, Switzerland
12. Emory University, Atlanta, Georgia
13. Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio
14. MD Anderson Cancer Center, Houston, Texas
15. Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
16. Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
17. McGill University Health Centre, Montreal, Québec, Canada
18. Intermountain Medical Center, Murray, Utah
19. Arizona Oncology Services Foundation, Tucson, Arizona
20. UPMC-Shadyside Hospital, Pittsburgh, Pennsylvania