ESTRO 2021 Abstract Book

S200

ESTRO 2021

Of the 311 patients enrolled, 306 patients were evaluable (156 in group A and 150 in group B). After a median follow-up of 43 months, the 3-year disease-free survival (DFS) was 73% in both groups (HR, 0.95, 95% CI, 0.63- 1.45, P = .82); the 3-year cumulative incidence of locoregional recurrence (6% v 5%, P = .67) and distant metastases (18% v 16%, P = .52) were not significantly different. Chronic toxicity grade 3-4 occurred in 11.8% and 9.9% in group A and B, respectively, at 3 years. The GHS/QoL score decreased after TME, but returned to pretreatment levels 1 year post-randomization with no difference between groups. Stool incontinence deteriorated 1 year post-randomization in both groups, and only improved slightly at 3 years, but never reached baseline levels. Conclusion Both groups resulted in comparable oncological outcomes. CRT followed by CT should be the preferred TNT sequence if organ preservation is a priority. This sequence resulted in higher pCR without compromising DFS, toxicity or QoL. The TNT regimen as tested in group B of the CAO/ARO/AIO-12 has, upon adaptation, been selected for comparison against TNT according to the RAPIDO protocol in the ongoing ACO/ARO/AIO-18.1 trial

(NCT04246684) of our group that uses 3-year organ preservation rate as primary endpoint. ClinicalTrials.gov: NCT02363374; On behalf of the German Rectal Cancer Study Group

Proffered papers: Proffered papers 17: Gynaecological

OC-0295 New Prognostic factors in locally advanced cervical cancer treated with MR-IGABT in EMBRACE Study. U. Mahantshetty 1 , M. Schmid 2 , C. Kirisits 3 , K. Tanderup 4 , C. Haie-Meder 5 , L. Fokdal 6 , A. Sturdza 7 , P. Hoskin 8 , B. Segredin 9 , K. Bruheim 10 , F. Huang 11 , B. Rai 12 , R. Cooper 13 , E. van der Steen-Banasik 14 , E. van Limbergen 15 , B. Pieters 16 , L.T. Tan 17 , R. Hawaldar 18 , S. Kannan 19 , R. Nout 20 , A. A.C. de Leeuw 21 , N. Nesvacil 22 , I. Jürgenliemk- Schulz 23 , J. Lindegaard 24 , R. Pötter 22 1 Tata Memorial Hospital, (Homi Bhabha Caner Hospital & Research Centre, Visakhapatnam), , Radiation Oncology , Vishakhapatnam, India; 2 Medical University of Vienna, Comprehensive Cancer Center, Department of Radiation Oncology-, Vienna, Austria; 3 Medical University of Vienna, Comprehensive Cancer Center, Department of Radiation Oncology, Vienna, Austria; 4 Aarhus University Hospital , Department of Oncology, Aarhus, Denmark; 5 Institute Gustave-Roussy , Department of Radiotherapy, Villejuif, France; 6 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark; 7 Medical University of Vienna, Comprehensive Cancer Center,, Department of Radiation Oncology, Vienna, Austria; 8 Mount Vernon Hospital, Mount Vernon Cancer Centre , Department of Radiotherapy , Northwood, United Kingdom; 9 Institute of Oncology Ljubljana, University of Ljubljana, Department of Radiotherapy,, Ljubljana, Slovenia; 10 The Norwegian Radium Hospital- Oslo University Hospital Norway, Department of Oncology, Oslo, Norway; 11 Cross Cancer Institute and University of Alberta, Department of Oncology, Edmonton, Canada; 12 Postgraduate Institute of Medical Education and Research , Department of Radiotherapy and Oncology,, Chandigarh, India; 13 St James's University Hospital, Leeds Cancer Centre, Department of Radiotherapy , Leeds, United Kingdom; 14 Radiotherapie groep Arnhem, Department of Radiotherapy, Arnhem, The Netherlands; 15 UZ Leuven, Department of Radiation Oncology, Leuven, Belgium; 16 Amsterdam University Medical Centers, University of Amsterdam, Department of Radiation Oncology,, Amsterdam, The Netherlands; 17 Addenbrooke´s Hospital, Cambridge University Hospitals, Department of Oncology, Cambridge, United Kingdom; 18 Tata Memorial Centre, Department of Clinical Research Secretariat, Mumbai, India; 19 ACTREC, Tata Memorial Centre, Department of Biostatisitcs, Navi Mumbai , India; 20 Leiden University Medical Center, Department of Radiation Oncology , Leiden, The Netherlands; 21 University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands; 22 Medical University of Vienna, Comprehensive Cancer Center, Department of Radiation Oncology , Vienna, Austria; 23 University Medical Centre Utrecht, , Department of Radiation Oncology , Utrecht, The Netherlands; 24 Aarhus University Hospital , Department of Oncology, Aarhus, Denmark Purpose or Objective The aim is to investigate prognostic factors affecting overall disease outcome and survival in patients treated with chemoradiation and MR Image Guided Adaptive Brachytherapy (IGABT) in the prospective observational multi-centre IntErnational study on MRI-guided BRAchytherapy in locally advanced CErvical Cancer (EMBRACE) study. Materials and Methods Between 2008-2015 a total of 1416 pts with LACC were prospectively enrolled in EMBRACE from 24 centers. Patient, tumor (clinical/ MRI at diagnosis & BT) and treatment related parameters (EBRT, Concomitant chemotherapy and BT details, dose volume parameters, total doses and overall treatment time) were analyzed. Disease Control (DC) was defined as absence of any recurrence or progression, Disease Free Survival (DFS) as absence of any disease event or death from any cause and Overall Survival (OS) as death from any cause, respectively. Kaplan-Meier method were used to estimate survival and Cox proportional regression models were used for multivariate analyses (MVA). Hazard Ratio’s (HR) & 95% Confidence Interval (CI) with a p-value < 0.05 were considered statistically significant. The model was carefully selected to define independent factors related with various patient, tumor and treatment parameters including age, FIGO stage, hemoglobin, clinical & MR tumor parameters, nodal involvement etc. Results 1341 patients were eligible for analysis. With a median follow up of 51 months, in total 331/ 1318 patients had events and/or deaths for DC, 427/1341 for DFS and 363 / 13 41 for OS. FIGO 2009 stage distribution was IB 241 (18%), IIA 67 (5%), IIB 683 (52%), IIIA 13 (1%), IIIB 183 (14%), IVA 34 (3%), IVB (para-aortic nodes) 97 (7%); 52% were node-positive, 82% had squamous Cell Carcinoma. Median (Inter Quartile Range [IQR]) high risk CTV volume was 28 (20, 40) cm3. Median (IQR) D90% was 90 (85, 94) Gy EQD2 .The overall DC, DFS and OS at 5 years was 74%, 68% and 74% respectively. Table 1 shows the hazard ratio (95% CI) and p-value of MVA for DC, DFS and OS. Presence of tumor necrosis at diagnosis, distal parametrial involvement and larger CTV HR volume at BT