ESTRO 2025 - Abstract Book

S1827

Clinical – Upper GI

ESTRO 2025

accumulated CBCT doses showed iCTV coverage >99% in all patients, supporting use of weekly cCT and adaptive radiotherapy to secure full target dose. Keywords: Radiotherapy, Esophageal cancer, Dosimetric effect References: [a] Mortensen H, Populaire P, Hoffmann L, Moeller D, Appelt A, et al. Proton versus photon therapy for esophageal cancer - A trimodality strategy (PROTECT) NCT050555648: A multicenter international randomized phase III study of neoadjuvant proton versus photon chemoradiotherapy in locally advanced esophageal cancer. Radiother Oncol. 2023;190. doi: 10.1016/j.radonc.2023.109980. [b] Hoffmann L, Mortensen H, Shamshad M, Berbee M, Bizzocchi N, Bütof P, et al. Treatment planning comparison in the PROTECT-trial randomising proton versus photon beam therapy in oesophagela cancer: Results from eight European centres. Radiotherapy and Oncology 2022; 172. https://doi.org/10.1016/j.radonc.2022.04.029. Digital Poster Baseline coronary artery calcification burden and cardiovascular risk in esophageal cancer patients undergoing radiotherapy: is intervention needed? Renliang Xue 1 , Mark L. Frederiks 1 , Rozemarijn Vliegenthart 2 , Johannes A. Langendijk 1 , Anne G.H. Niezink 1 , Anne Crijns 1 , Robin Wijsman 1 , Christina T. Muijs 1 1 Department of Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands. 2 Department of Radiology, University Medical Center Groningen, Groningen, Netherlands Purpose/Objective: Radiation-induced cardiac events (RICE) are a growing concern for esophageal cancer (EC) patients receiving radiotherapy (RT) [1]. Current guidelines recommend pre-RT cardiovascular evaluation and cardiology consultation in high-risk patients [2]. Therefore, this study primarily aims to assess the baseline levels of two established cardiovascular risk factors in this population: coronary artery calcification (CAC) burden [3] and cardiovascular disease (CVD) risk score [4]. Our secondary aims are to estimate the percentage of patients who may benefit from cardiology consultation based on these factors and to identify very high-risk patients by considering cardiac radiation exposure. Material/Methods: We included EC patients who received definitive RT, chemo-RT, or neoadjuvant chemo-RT between 2018-2022. CAC burden was quantified by Agatston Score [5] on 4D-planning computed tomography. CAC-score categories were defined as 0, 1–99, 100–399, and ≥400, indicating no, low, moderate, and high burden. Patients with established coronary disease were excluded from CAC-scoring. The baseline CVD risk score was calculated in asymptomatic patients using the SCORE2 cardiovascular risk assessment tool, categorizing them into low, moderate, and high risk groups for CVD over a ten-year period [2,4]. Ordinal logistic regression was used to identify factors associated with higher CAC burden. High-dose cardiac exposure was defined as: mean heart dose ≥15Gy [1,2]. Results: 498 patients were included. The distribution of CAC burden was: none (18.1%), low (17.7%), moderate (17.9%), and high (26.9%), with the remaining 19.5% having established coronary disease (Figure 1A). Multivariate analysis showed that higher CAC burden was independently associated with older age, male sex and hypertension. 30.5% of patients had established CVD, while the remaining asymptomatic patients were categorized into low (13.7%), moderate (35.7%), and high (20.1%) baseline CVD risk groups (Figure 1B). In accordance with guidelines, 37.3% of asymptomatic patients require cardiology consultation based on the findings of high CAC burden and/or high baseline CVD risk [2,3]. By including cardiac radiation exposure, 5.6% of asymptomatic patients were identified as 3414