Institute of Medical Biostatistics, Epidemiology, and Informatics (IMBEI), University Medical Centre Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany. singers@uni-mainz.de. University Cancer Centre, University Medical Centre Mainz, Mainz, Germany. singers@uni-mainz.de. Department of Medical Psychology and Medical Sociology, University Medical Centre Leipzig, Leipzig, Germany. Department of Neurosurgery, University Medical Centre Leipzig, Leipzig, Germany. Department of Obstetrics and Gynecology, University Medical Centre Leipzig, Leipzig, Germany. Department of Otolaryngology, University Medical Centre Leipzig, Leipzig, Germany. Department of Radiation-Oncology, University Medical Centre Leipzig, Leipzig, Germany. Department of Urology, University Medical Centre Leipzig, Leipzig, Germany. Department of Psychosomatic Medicine and Psychotherapy, University Medical Centre Leipzig, Leipzig, Germany. Institute of Medical Sociology, University of Halle, Halle, Germany.