ESTRO 2025 - Abstract Book

S1179

Clinical – Lower GI

ESTRO 2025

Keywords: Radiotherapy, Rectal, Patients

References: 1. Brehaut JC, O'Connor AM, Wood TJ, et al. Validation of a decision regret scale. Med Decis Making . 2003;23(4):281 292. doi:10.1177/0272989X03256005 2. Hanna CR, O'Cathail SM, Graham JS, et al. Durvalumab (MEDI 4736) in combination with extended neoadjuvant regimens in rectal cancer: a study protocol of a randomised phase II trial (PRIME-RT) [published correction appears in Radiat Oncol. 2021 Dec 2;16(1):230. doi: 10.1186/s13014-021-01941-z]. Radiat Oncol . 2021;16(1):163. Published 2021 Aug 26. doi:10.1186/s13014-021-01888-1

1735

Proffered Paper Organ preservation and quality of life after TNT for locally advanced rectal cancer: a study of the German Rectal Cancer Study Group (CAO/ARO/AIO-16) Cihan Gani 1 , Emmanouil Fokas 2 , Bülent Polat 3 , Oliver J Ott 4 , Markus Diefenhardt 5 , Alfred Königsrainer 6 , Simon Boeke 1 , Andreas Kirschniak 7 , Robert Bachmann 6 , Dörte Wichmann 8 , Michael Bitzer 8 , Stephan Clasen 9 , Ulrich Grosse 10 , Rüdiger Hoffmann 11 , Martin Götz 12 , Ralf-Dieter Hofheinz 13 , Elisabeth Germer 14 , Rainer Fietkau 4 , Peter Martus 15 , Daniel Zips 16 , Claus Rödel 5 1 Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany. 2 Department of Radiation Oncology, University Hospital Cologne, Cologne, Germany. 3 Department of Radiation Oncology, University Hospital Würzburg, Würzburg, Germany. 4 Department of Radiation Oncology, University Hospital Erlangen, Erlangen, Germany. 5 Department of Radiation Oncology, University Hospital Frankfurt, Frankfurt am Main, Germany. 6 Department of Surgery, University Hospital Tübingen, Tübingen, Germany. 7 Department of Surgery, Klinikum Maria Hilf, Möchengladbach, Germany. 8 Department of Internal Medicine, University Hospital Tübingen, Tübingen, Germany. 9 Department of Radiology, Klinikum am Steinenberg, Reutlingen, Germany. 10 Department of Radiology, Klinkum Frauenfeld, Frauenfeld, Switzerland. 11 Department of Radiology, University Hospital Tübingen, Tübingen, Germany. 12 Department of Internal Medicine, Klinikum Böblingen, Böblingen, Germany. 13 Department of Internal Medicine, Mannheim University Hospital, Mannheim, Germany. 14 Comprehensive Cancer Center, University Hospital Würzburg, Würzburg, Germany. 15 Department of Medical Biometry and Statistics, University Hospital Tübingen, Tübingen, Germany. 16 Department of Radiation Oncology, Charite, Berlin, Germany Purpose/Objective: Total neoadjuvant therapy (TNT) has been shown to increase pathological complete response (pCR) and disease free survival in rectal cancer, however, prospective data on organ preservation, quality of life, and functional outcomes after TNT is still limited. Material/Methods: Patients with cT1/2N1-2 or cT3N0/N1-2 rectal cancer up to 12 cm from the anal verge received chemoradiotherapy (CRT) with 50.4 Gy and concomitant fluorouracil and oxaliplatin followed by three cycles of fluorouracil, leucovorin, and oxaliplatin (FOLFOX) according to our previous CAO/ARO/AIO-12-trial. Patients with a clinical complete response (cCR) were assigned to a watch&wait (W&W) approach. The primary endpoint of this multicenter, phase-II-trial was the cCR rate, secondary endpoints included long-term oncological endpoints, toxicity according to CTC-AEv5.0, quality of life and organ function assessed by the low anterior resection syndrome (LARS) score and Wexner Score for fecal incontinence. Results: Of 91 patients receiving TNT, 34 patients (37%) achieved a cCR. Two further patients had local excision of residual findings with pCR after TNT, resulting in 36 (40%) of patients assigned to organ preservation. Three-year TME-free survival was 21% (95% CI, 14-32%). Patients who remained TME-free showed significantly lower LARS scores