1. From the Leiden University Medical Center, Leiden; Comprehensive Cancer Centre South; Catharina Hospital, Eindhoven; Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilberg; University Medical Center Utrecht, Utrecht; Medisch Spectrum Twente, Enschede; Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam; MAASTtricht Radiation Oncology Clinic, Maastricht; and University Medical Center Groningen, Groningen, the Netherlands.