¹Regional Cancer Centre, Department of Radiation Oncology, Thiruvananthapuram, India; ²Regional Cancer Centre , Department of Radiation Oncology, Thiruvananthapuram, India; ³Regional Cancer Centre, Department of Cancer Epidemiology & Biostatistics, Thiruvananthapuram, India; ⁴Regional Cancer Centre, Department of Radiation Oncology, Thiruvananthapuram,, India

¹University Hospital Zürich, Radiation Oncology, Zürich, Switzerland; ²University Hospital Zürich , Radiation Oncology, Zürich, Switzerland; ³University Hospital Zürich and University of Zürich, Radiation Oncology, Zürich, Switzerland

¹Royal Marsden Hospital, Radiotherapy, London, United Kingdom; ²Institute of Cancer Research, Radiotherapy and Imaging, London, United Kingdom; ³Royal Marsden Hospital, Health Research, London, United Kingdom; ⁴St George's University of London, Radiography, London, United Kingdom; ⁵Royal Marsden Hospital, Clinical Trials, London, United Kingdom

¹University Hospital Zürich, University of Zürich , Department of Radiation Oncology, Zürich, Switzerland; ²Università degli Studi di Torino, Radiation Oncology, Torino, Italy; ³Humanitas University, Pieve Emanuele (Milan), IRCCS Humanitas Research Hospital, Rozzano and Department of Biomedical Sciences, Milan, Italy; ⁴Universitair Ziekenhuis Gent, Radiation Oncology, Gent, Belgium; ⁵University of Brescia and IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Radiation Oncology, Negrar, Italy; ⁶Azienda Ospedaliero-Universitaria Careggi Florence, Radiation Oncology, Florence, Italy; ⁷Radboud University Medical Center Nijmegen, Radiation Oncology, Nijmegen, The Netherlands; ⁸University of Milan, Milan, Italy and Division of Radiotherapy, IEO European Institute of Oncology, IRCCS, Department of Oncology and Hemato-oncology, Milan, Italy; ⁹Campus Kennedylaan, AZ Groeninge Kortrijk , Kortrijk, Belgium; ¹⁰Onze-Lieve-Vrouw Ziekenhuis, Radiation Oncology, Aalst, Belgium; ¹¹Catharina Ziekenhuis, Radiation Oncology, Eindhoven, The Netherlands; ¹²Hopital de Sion, Hopital du Valais , Sion, Switzerland; ¹³Universitario Campus Bio-Medico- Oncology Center, Policlinico , Roma, Italy; ¹⁴Hôpitaux universitaires de Genève - HUG - site de Cluse-Roseraie, Radiation Oncology, Geneva, Switzerland; ¹⁵Cliniques Universitaires Saint-Luc, Radiation Oncology, Brussels, Belgium; ¹⁶Inselspital, Universitätsspital , Radiation Oncology, Bern, Switzerland; ¹⁷Istituti Clinici Scientifici Maugeri, Radiation Oncology, Pavia, Italy; ¹⁸Division of Radiation Oncology, Institute of Oncology , Ljubljana, Slovenia; ¹⁹Radiotherapiegroep, Deventer, the Netherlands, Radiotherapiegroep, Deventer, the Netherlands, Deventer, The Netherlands; ²⁰European Organisation for Research and Treatment of Cancer (EORTC) , Headquarters, Brussels, Belgium

¹San Raffaele Scientific Institute, Radiotherapy, Milan, Italy; ²IRCCS Istituto Nazionale dei Tumori “Regina Elena", Radiotherapy, Rome, Italy; ³Cliniche Gavazzeni Humanitas, Radiotherapy, Bergamo, Italy; ⁴Ospedale Regionale Parini-AUSL Valle d’Aosta, Radiotherapy, Aosta, Italy; ⁵Fondazione IRCCS Istituto Nazionale dei Tumori, Radiotherapy, Milan, Italy; ⁶A.O. SS. Antonio e Biagio, Radiotherapy, Radiotherapy, Alessandria, Italy; ⁷Ospedale di Ivrea, Radiotherapy, Ivrea, Italy; ⁸Azienda Sanitaria dell’Alto Adige, Radiotherapy, Bolzando, Italy; ⁹Azienda Ospedaliero Universitaria S. Maria della Misericordia, , Radiotherapy, Udine, Italy; ¹⁰IRCCS Istituto Nazionale dei Tumori “Regina Elena”, Radiotherapy, Rome, Italy; ¹¹IRCC Candiolo, Radiotherapy, Candiolo, Italy; ¹²Azienda Sanitaria dell’Alto Adige, Radiotherapy, Bolzano, Italy; ¹³Fondazione IRCCS Istituto Nazionale dei Tumori - Prostate Program, Radiotherapy, Milan, Italy; ¹⁴Ospedale degli Infermi, Radiotherapy, Biella, Italy; ¹⁵Azienda Ospedaliero Universitaria S. Maria della Misericordia, Radiotherapy, Udine, Italy; ¹⁶Fondazione IRCCS Istituto Nazionale dei Tumori, Prostate Program - Università degli Studi Milano, Radiotherapy, Milan, Italy; ¹⁷San Raffaele Scientific Institute, Medical Physics, Milan, Italy; ¹⁸Università Vita Salute San Raffaele, Radiotherapy, Milan, Italy

(1)University Hospitals Leuven, Department of Radiation Oncology, Leuven, Belgium;(2)KU Leuven, Department of Oncology, Leuven, Belgium;(3)The Netherlands Cancer Institute, Department of Radiation Oncology, Amsterdam, The Netherlands;(4)University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands;(5)University Medical Centre Utrecht, Julius Centre for Healthe Sciences and Primary Care, Utrecht, The Netherlands;(6)Radboud University Medical Centre, Department of Radiation Oncology, Nijmegen, The Netherlands;