1. Norwegian Radium Hospital, Oslo, Norway; St. James's University Hospital, Leeds, United Kingdom; Medical Research Council Clinical Trials Unit, London, United Kingdom; Klinikum Solingen, Solingen, Germany; UCL Cancer Institute and UCL Hospitals, London, United Kingdom; Centre François Baclesse, Caen, France; Vancouver Coastal Health, Vancouver, BC, Canada; Sydney Cancer Centre, Sydney, Australia; Hospital Clinico Universitario, Valencia, Spain; Princess Margaret Hospital, Toronto, ON, Canada