ESTRO 2020 Abstract book

S345 ESTRO 2020

of severe fistula, bleeding and stricture events. All endpoints had a crude incidence of grade 3-5 between 0.5% and 2.8%. In total, 102 patients (8.2%) experienced grade 3-5 events, 40 patients (39%) within the first year, 68 patients (67%) within the first 2 years, and 86 patients (84%) within the first 3 years. Table 2 shows grade 3-5 events according to FIGO stage and CTV HR volume. FIGO stage and CTV HR volume significantly affected crude incidences of ureter strictures and fistulas. Ureter strictures and fistulas occurred in 0.8% and 1.3% of patients with FIGO stage I-II, whereas the risk was considerably higher in patients with stage III (8.3% and 7.7%) and stage IVA (16.7% and 20.0%).

favourably with previous reports on conventional brachytherapy. EMBRACE is the largest prospective study on radio(chemo)therapy with MR IGABT for LACC to date and will provide a benchmark for future studies.

Proffered Papers: Proffered papers 29 : Head and neck

OC-0570 Validating gene signatures in locally advanced HNSCC patients treated by PORT-C and in xenografts S. Patil 1,2,3 , A. Linge 1,3,4,5 , B. Tawk 6,7,8 , K. Gurtner 1,3,4 , M. Großer 9 , F. Lohaus 1,3,4,5 , V. Gudziol 5,10 , A. Nowak 5,11 , I. Tinhofer 12,13 , V. Budach 12,13 , M. Stuschke 14,15 , P. Balermpas 16,17 , C. Rödel 16,17 , H. Schäfer 18,19 , A. Grosu 18,19 , A. Abdollahi 6,7,8,20,21 , J. Debus 6,8,20,21,22 , C. Belka 23,24,25 , S.E. Combs 25,26,27 , D. Mönnich 28,29 , D. Zips 28,29 , G.B. Baretton 3,5,9,30 , M. Krause 1,2,3,4,5 , M. Baumann 1,4,31 , S. Löck 1,3,4 1 OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden- Helmholtz-Zentrum Dresden – Rossendorf, Dresden, Germany ; 2 Helmholtz-Zentrum Dresden – Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany ; 3 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK partner site Dresden, Dresden, Germany ; 4 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden, Dresden, Germany ; 5 National Center for Tumor Diseases NCT, Partner Site Dresden, Dresden, Germany ; 6 Heidelberg Institute of Radiation Oncology HIRO, National Center for Radiation Research in Oncology NCRO- University of Heidelberg Medical School and German Cancer Research Center DKFZ, Heidelberg, Germany ; 7 Translational Radiation Oncology, University of Heidelberg Medical School and German Cancer Research Center DKFZ, Heidelberg, Germany ; 8 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK- partner site Heidelberg, Heidelberg, Germany ; 9 Institute of Pathology, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden, Dresden, Germany ; 10 Department of Otorhinolaryngology, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden, Dresden, Germany ; 11 Department of Oral and Maxillofacial Surgery, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden, Dresden, Germany ; 12 Department of Radiooncology and Radiotherapy, Charité University Medicine, Berlin, Germany ; 13 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK- partner site Berlin, Berlin, Germany ; 14 Department of Radiotherapy- Medical Faculty, University of Duisburg-Essen, Essen, Germany ; 15 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK- partner site Essen, Essen, Germany ; 16 Department of Radiotherapy and Oncology, Goethe-University Frankfurt, Frankfurt, Germany ; 17 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK- partner site Frankfurt, Frankfurt, Germany ; 18 Department of Radiation Oncology- Medical Center- Medical Faculty, University of Freiburg, Freiburg, Germany ; 19 German Cancer Research Center DKFZ- Heidelberg, German Cancer Consortium DKTK- partner site Freiburg, Freiburg, Germany ; 20 Clinical Cooperation Unit

Conclusion This report shows limited morbidity (≤ 8.2%) regarding grade 3-5 gastrointestinal and urinary bleeding, strictures and fistulas. Morbidity in patients with FIGO stage I-II was particularly low (5.2%). Bleeding and gastrointestinal stenosis seemed unrelated to FIGO stage and CTV HR volume, whereas fistulas and ureter strictures increased with a larger CTV HR volume and higher FIGO stage (III and IVA). This indicates that the local tumour extent significantly contributes to increased risk of ureter strictures and fistulas. The incidences reported in this analysis compare