1. Department of Palliative Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
2. Department of Psychosomatic Medicine and Psychotherapy, West German Cancer Center, LVR-Klinikum Essen, University of Duisburg-Essen, 45122 Essen, Germany
3. Directorate of Nursing, University Hospital Essen, 45122 Essen, Germany
4. Department of Medical Oncology, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany