1 Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
2 Department of Radiation Oncology, New York Proton Center, New York, NY, USA; Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
3 Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, Netherlands.
4 Department of Radiotherapy, Leiden University Medical Centre, Leiden, Netherlands; Centre of Expertise in Palliative Care, Leiden University Medical Centre, Leiden, Netherlands.
5 Mount Vernon Cancer Centre, Northwood, UK; Division of Cancer Sciences, University of Manchester, Manchester, UK.
6 Department of Radiation Oncology, National University Cancer Institute, National University Hospital, Singapore, Singapore; Department of Clinical Oncology, Tuen Mun Hospital, New Territories West Cluster, Hospital Authority, Hong Kong, China.
7 Department of Oncology, Princess Margaret Hospital, Kowloon West Cluster, Hospital Authority, Hong Kong, China.
8 Department of Medicine, University of California, Los Angeles, CA, USA.
9 Department of Radiation Oncology, Princess Margaret Cancer Center, Toronto, Canada.
10 Department of Radiation Oncology, University of Lübeck, Lübeck, Germany.
11 Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
12 Division of Cancer Sciences, University of Manchester, Manchester, UK; Department of Clinical Oncology, Christie NHS Foundation Trust, Manchester, UK.
13 Radiotherapy Department II, Greater Poland Cancer Centre, Poznan, Poland; Electroradiology Department, University of Medical Sciences, Poznan, Poland.
14 Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
15 Department of Radiation Oncology, Hospital Sírio-Libanês, São Paulo, Brazil; Latin America Cooperative Oncology Group (LACOG), Porto Alegre, Brazil.
16 Department of Radiation Oncology, Bank of Cyprus Oncology Centre, Strovolos, Cyprus.
17 Department of Radiation Oncology, University of Minnesota Medical School, Minneapolis, MN, USA.
18 Department of Radiation Oncology, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
19 Department of Radiation Oncology, University Hospital Leuven, Leuven, Belgium.