Department of Medical Oncology, Radboud University Medical Center, Postbox 9101, 6500 HB, Nijmegen, The Netherlands. Department of Internal Medicine, Northwest Clinics, Alkmaar, The Netherlands. Department of Internal Medicine, Medical Center Leeuwarden, Leeuwarden, The Netherlands. Department of Radiation Oncology, Radiotherapeutic Institute Arnhem, Arnhem, The Netherlands. Department of Medical Oncology, Maastricht University Medical Center, Maastricht, The Netherlands. Department of Medical Oncology, Leiden University Medical Center, Leiden, The Netherlands. Department of Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Postbox 9101, 6500 HB, Nijmegen, The Netherlands. Biostatistics, Radboud Institute for Health Sciences, Radboud University Medical Center, Postbox 9101, 6500 HB, Nijmegen, The Netherlands. Department of Radiation Oncology, Radboud University Medical Center, Postbox 9101, 6500 HB, Nijmegen, The Netherlands. Department of Medical Oncology, Radboud University Medical Center, Postbox 9101, 6500 HB, Nijmegen, The Netherlands. Electronic address: Carla.vanHerpen@radboudumc.nl.