Statistical and Data Management Department, American College of Radiology, Philadelphia, Pennsylvania, USA;3. School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA;4. Institute for Cancer Outcomes and Survivorship, University of Alabama at Birmingham, Birmingham, Alabama, USA;5. Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri, USA;6. Radiation Oncology Department of Radiation Oncology, Edmonton Cross Cancer Institute, Edmonton, Alberta, Canada;7. Department of Radio Oncology, CHUM - Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada;8. Radiation Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA;9. Department of Radiation Oncology, UCSF Medical Center-Mount Zion, San Francisco, California, USA;10. Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan, USA;11. Department of Radiation Oncology, University of Maryland/Greenebaum Cancer Center, Baltimore, Maryland, USA;12. Department of Radiation Oncology, University of California Davis, Sacramento, California, USA;13. Department of Oncology, Tom Baker Cancer Centre, Calgary, Alberta, Canada;14. The Research Institute, McGill University Health Centre (MUHC), Montreal, Quebec, Canada;15. Department of Oncology, London Regional Cancer Program, London, Ontario, Canada;16. Department of Radiation Oncology, University of Rochester, Rochester, New York, USA;17. Department of Radiation Oncology, Summa Health System - Akron Campus, Akron, Ohio, USA;18. Department of Radiation Oncology, UCSF Medical Center-Mission Bay, San Francisco, California, USA;19. Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California, USA