¹University Hospital Zurich, Radiation Oncology, Zurich, Switzerland; ²North Carolina State University, Mathematics, Raleigh, USA

(1)Medical University Vienna, Department of Radiation Oncology, Vienna, Austria;(2)Aarhus University Hospital, Department of Oncology, Aarhus, Denmark;(3)Gustave-Roussy, Department of Radiotherapy, Villejuif, France;(4)Mount Vernon Hospital, Mount Vernon Cancer Centre, Northwood, United Kingdom;(5)Tata Memorial Hospital, Department of Radiation Oncology, Mumbai, India;(6)Institute of Oncology Ljubljana, Department of Radiotherapy, Ljubljana, Slovenia;(7)The Norwegian Radium Hospital- Oslo University Hospital, Department of Oncology, Oslo, Norway;(8)Cross Cancer Institute and University of Alberta, Department of Oncology, Edmonton, Canada;(9)Postgraduate Institute of Medical Education and Research, Department of Radiotherapy and Oncology, Chandigarh, India;(10)St James's University Hospital, Leeds Cancer Centre, Leeds, United Kingdom;(11)Radiotherapiegroep Arnhem, Department of Radiotherapy, Arnhem, The Netherlands;(12)UZ Leuven, Department of Radiation Oncology, Leuven, Belgium;(13)Amsterdam UMC- Academic Medical Center- University of Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands;(14)Addenbrooke´s Hospital- Cambridge University Hospitals, Department of Oncology, Cambridge, United Kingdom;(15)Leiden University Medical Center, Department of Radiation Oncology, Leiden, The Netherlands;(16)University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands;(17)EMBRACE Collaborative Group, EMBRACE Collaborative Group, EMBRACE Collaborative Group, Austria;