1. Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;
2. Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark;
3. Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA;
4. Manchester Cancer Research Centre, Division of Cancer Sciences, The University of Manchester, Manchester, UK;
5. Clinical Trial Service Unit, Nuffield Department of Population Health, University of Oxford, UK;
6. University of Maryland Medical Center, Baltimore, MD, USA;
7. Greenebaum Comprehensive Cancer Center, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA