ESTRO 2025 - Abstract Book

S1173

Clinical – Lower GI

ESTRO 2025

2. STAR-TREC phase II: Can we save the rectum by watchful waiting or transanal surgery following (chemo)radiotherapy versus total mesorectal excision for early rectal cancer? Bach SP, deWilt JHW, Peters F, et al. Journal of Clinical Oncology 2022 Vol. 40 Issue 16_suppl Pages 3502-3502 DOI: 10.1200/JCO.2022.40.16_suppl.3502 3. STAR-TREC Phase III protocol. Bach SP, STAR-TREC Collaborative. Colorectal Disease 2022. https://doi.org/10.1111/codi.16056

1539

Poster Discussion Neoadjuvant treatment of rectal cancer: A UK-wide audit after implementation of national IMRT guidance Archie Macnair 1 , Richard Adams 2,3 , Ane Appelt 4,5 , Mark Beavon 6 , Karl Drinkwater 6 , Catherine R Hanna 7 , Sean M O’Cathail 8 , Rebecca Muirhead 9 1 Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom. 2 Centre for Trials Research, Cardiff University, Cardiff, United Kingdom. 3 Velindre Cancer Centre, Velindre University NHS trust, Cardiff, United Kingdom. 4 Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom. 5 Department of Medical Physics, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom. 6 Education and Professional Practice, Royal College of Radiologists, London, United Kingdom. 7 School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom. 8 Dept of Radiation Oncology, UCC/CUH Cancer Research Centre, Cork, Ireland. 9 Department of Oncology, Oxford University Hospitals University Foundation Trust, Oxford, United Kingdom Purpose/Objective: Rectal cancer management has changed significantly in the last 5 years with the introduction of total neo-adjuvant therapy (TNT), minimally invasive surgery, brachytherapy and organ preservation. A national survey of the use of Intensity modulated radiotherapy (IMRT) for rectal cancer management was carried out in 2020, to help develop national Royal College of Radiologists (RCR) Guidance, published 2021. We performed a repeat survey, to inform iterations of the RCR Guidance and establish treatment patterns across the UK. Material/Methods: A web-based survey was disseminated by the RCR to all UK radiotherapy centres. The survey requested details of radiotherapy techniques in current use, including details on set up, dose & fractionation schedules, organs at risk (OAR), peer review, and verification, and asked for the standard management of 5 clinical cases within each multidisciplinary (MDT) serving that radiotherapy centre. Figure 1 details the clinic questions. Descriptive statistical analysis was carried out.