ESTRO 2025 - Abstract Book

S1275

Clinical – Lower GI

ESTRO 2025

Conclusion: The absence of TNT is associated with poorer overall survival in locally advanced rectal cancer treated with hypofractionated radiotherapy. Tumor stage remains the primary determinant of the disease-free interval. These real-world clinical practice results support the implementation of TNT in the standard therapeutic protocol.

Keywords: Rectal cancer, Hypofractionation, Overall Survival

References: Nilsson, P., & al., et al. (2021). Total Neoadjuvant Therapy with Short-Course Radiation in Locally Advanced Rectal Cancer (RAPIDO): A Randomized Phase III Trial. The Lancet Oncology , 22(7), 947-957. https://doi.org/10.1016/S1470 2045(21)00353-4 Liu, S., Jiang, T., Xiao, L., & otros. (2021). Total neoadjuvant therapy (TNT) versus standard neoadjuvant chemoradiotherapy for locally advanced rectal cancer: A systematic review and meta-analysis. International Journal of Colorectal Disease, 36(5), 1041-1051. https://doi.org/10.1007/s00384-021-03869-

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Digital Poster PATHOLOGICAL COMPLETE RESPONSE AND MRI FEATURES IN LOCALLY ADVANCED RECTAL CANCER: A MONO INSTITUTIONAL EXPERIENCE Marco Lucarelli 1 , Giulia de Pasquale 1 , Rosario Bonelli 1 , Monica Di Tommaso 1 , Angelo Di Pilla 1 , Andrea Delli Pizzi 2 , Consuelo Rosa 1 , Andrea D'Aviero 1,3 , Marta Di Nicola 3 , Domenico Genovesi 1,3 1 Department of Radiation Oncology, "S.S. Annunziata" Hospital, Chieti, Italy. 2 Department of Radiology, "S.S. Annunziata" Hospital, Chieti, Italy. 3 Department of Medical, Oral and Biotechnological Sciences, “G. D’Annunzio” University of Chieti, Chieti, Italy Purpose/Objective: In the setting of neoadjuvant Chemoradiotherapy (CRT) for Locally Advanced Rectal Cancer (LARC), a single-institution experience was reported to evaluate the impact of Magnetic Resonance Imaging (MRI) features on Disease Free Survival (DFS) and Local Control (LC). Material/Methods: From 2018 to 2024, 101 patients with LARC were retrospectively analyzed. All patients underwent CRT with a simultaneous integrated boost (55 Gy, 2,2 Gy/fraction) and concomitant Capecitabine. Clinic-pathological characteristics and radiological post-treatment MRI features (mesorectal tumor invasion (MTI), circumferential