ESTRO 2025 - Abstract Book

Brachytherapy - Gastro-intestinal, paediatric brachytherapy, miscellaneous

S184

ESTRO 2025

Conclusion: The proposed models offer a tailored approach for predicting OS and RFS in LARC patients who are considering organ preservation treatment involving a CXB boost. The models demonstrate strong predictive performance to identify high risk patients; however, model calibration needs to be assessed by additional external validation. Future research should focus on identification of novel biomarkers to enhance predicative accuracy, particularly for tumour regrowth.

Keywords: Rectal Cancer, Prediction Model, Brachytherapy

References: (1) Baidoun F, Elshiwy K, Elkeraie Y, et al. Colorectal cancer epidemiology: recent trends and impact on outcomes. Curr Drug Targets. 2021;22(9):998-1009. doi:10.2174/1389450121999201117115717 (2) Bromham N, Kallioinen M, Hoskin P, Davies RJ, Guideline Committee. Colorectal cancer: summary of NICE guidance. BMJ. 2020;368.doi:10.1136/bmj.m461 (3) Stewart AJ, Van Limbergen EJ, Gerard JP, et al. GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer. Clin Transl Radiat Oncol. 2021;33:15-22. doi:10.1016/j.ctro.2021.12.004 (4) Moons KG, Altman DG, Reitsma JB, et al. TRIPOD explanation and elaboration. Ann Intern Med. 2015;162(1).doi:10.7326/M14-0698

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Proffered Paper Evaluating the Impact of Neoadjuvant Radiotherapy Modalities on Lymphocyte Preservation and Pathological Complete Response in Rectal Cancer Emma Starr 1 , Norma Ybarra 1,2 , Te Vuong 1,3 1 Division of Clinical and Translational Research, McGill University, Montreal, Canada. 2 Medical Physics Unit, McGill University, Montreal, Canada. 3 McGill Centre for Translational Research in Cancer, McGill University, Montreal, Canada