1. Eberhard-Karls-University Tuebingen, Department of Radiation Oncology , Tuebingen , Germany
2. RKH-Kliniken Ludwigsburg, Department of Radiation Oncology and Radiotherapy , Ludwigsburg , Germany
3. German Cancer Consortium (DKTK) Partnersite Tuebingen, German Cancer Research Center (DKFZ) Heidelberg , Germany
4. Charité University Hospital, Department of Radiation Oncology and Radiotherapy , Berlin , Germany
5. Eberhard-Karls-University Tuebingen, Department for Radiology , Tuebingen , Germany
6. Eberhard-Karls-University Tuebingen, Department of Orthopaedic Surgery , Tuebingen , Germany
7. Eberhard-Karls-University Tuebingen, Department of Pathology , Tuebingen , Germany
8. Medical University Vienna, AKH, Comprehensive Cancer Center, Department of Radiation Oncology , Wien , Austria