IRCCS Humanitas Research Hospital, University Hospital Zurich, Iridium Netwerk, Netherlands Cancer Institute, affiliation not provided to SSRN, Erasmus University Medical Center Rotterdam - Erasmus MC Cancer Institute, University of Lille II - Centre Oscar Lambret, Department of Radiation Oncology, Amsterdam University Medical Centers, Heidelberg University - University Medical Centre Mannheim, KU Leuven - University Hospitals Leuven, University of Copenhagen - Copenhagen University Hospital, affiliation not provided to SSRN, Medical University of Lodz, affiliation not provided to SSRN, University Hospitals Bristol - University Hospitals Bristol and Weston NHS Foundation Trust, Universidad de Alcalá - Hospital Universitario Ramón y Cajal, affiliation not provided to SSRN, affiliation not provided to SSRN, Scientific Institute for Research, Hospitalization and Healthcare (IRCCS) - Ospedale Sacro Cuore Don Calabria, University of Yamanashi, University of Toronto, University of Toronto - Sunnybrook Research Institute, University of Washington, University of Amsterdam - University Medical Center, University Hospital Zurich - Department of Radiation Oncology and Humanitas University