1 Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
2 Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
3 Mount Vernon Cancer Centre, Northwood, UK; Division of Cancer Sciences, University of Manchester, Manchester, UK.
4 Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA.
5 Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
6 Department of Radiation Oncology, University Hospital Leuven, Leuven, Belgium.
7 Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands; Leiden University Medical Center, Leiden, The Netherlands.
8 Department of Radiation Oncology, the University of Texas MD Anderson Cancer Center, Houston, TX, USA.
9 Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
10 Department of Health Outcomes and Behavior, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA; Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
11 Eastern Woods Radiation Oncology, Blanchard Valley Health Organization, Findlay, OH, USA.
12 Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
13 Radiotherapy Department II, Greater Poland Cancer Centre, Poznan, Poland; Department of Electroradiology, Poznań University of Medical Sciences, Poznań, Poland.
14 Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland; Department of Radiotherapy I, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland.
15 Department of Radiation Oncology, Hospital Sírio-Libanês, Sao Paulo, Brazil.