1. Department of Radiotherapy, University of Duisburg-Essen, Hufelandstr. 55, 45147 Essen, Germany
2. Department of Urology, University of Duisburg-Essen, 45147 Essen, Germany
3. German Cancer Consortium (DKTK), Partner Site University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany