S1067
Clinical – Upper GI
ESTRO 2026
Spain. 8 Nuclear Medicine, Hospital Clínic of Barcelona, Barcelona, Spain. 9 Department of Anesthesia and Perioperative Care, Hospital Clínic of Barcelona, Barcelona, Spain Purpose/Objective: Neoadjuvant therapy for distal esophageal and gastroesophageal junction (GEJ) adenocarcinoma has gained renewed interest in the context of evolving treatment approaches. This study compared pathological response, nodal downstaging, recurrence, and survival between chemoradiotherapy (NCRT) and chemotherapy (NCT), and evaluated the prognostic value of tumor regression grade (TRG). Material/Methods: A retrospective study included 59 patients with locally advanced distal esophageal and GEJ adenocarcinoma treated with NCRT (CROSS scheme; n = 34) or NCT (FLOT scheme; n = 25) at a tertiary center (2017–2024). Overall, 51 patients (86%) underwent curative surgery after neoadjuvant therapy (28/34 in NCRT, 23/25 in NCT). Clinical, pathological, and survival data were analyzed. TRG was assessed using the modified Ryan score (mRS 0–3), with major pathological response (MPR) defined as mRS 0–1. Pathological response and survival outcomes were compared. Overall survival (OS) was analyzed on an intention-to-treat basis using Kaplan–Meier and log-rank tests; prognostic factors were evaluated with multivariable Cox regression. Results: Median age was 66 years in both groups. Siewert II–III tumors were more frequent in NCT (72%), whereas Siewert I and distal esophageal tumors predominated in NCRT (79.4%). The clinical stage was cT3/T4 in 80% of NCT and 88.2% of NCRT patients. cN+ was higher in NCT (96%) vs. NCRT (79.4%). The complete pathological response (pCR) rate was 17.9% in NCRT vs. 8.7% in NCT. Pathological nodal downstaging (pN0) was more frequent after NCRT (46.4%) than NCT (26.1%), and MPR occurred in 42.9% vs. 17.3%, respectively (p = 0.051). OS did not differ significantly between groups (log-rank p = 0.61). However, OS correlated with TRG (log-rank p = 0.032), which was an independent prognostic factor (p = 0.018). Within the NCRT subgroup, survival improved progressively with lower TRG scores (p = 0.043). Patients with poor or absent tumor regression (mRS 3) had a 7.9-fold higher risk of death compared to those with MPR (HR 7.93; 95% CI, 2.18–28.8; p = 0.002). Systemic progression was the predominant pattern (90.5% in NCRT vs. 75% in NCT).
Conclusion: We present the first validated multicentre model that robustly stratifies 2-year mortality risk by integrating patient, tumour, and radiotherapy data in oesophageal cancer patients treated with nCRT. It provides a quantitative tool to identify high-risk patients who may benefit from treatment escalation (e.g. FLOT for AC) and low-risk patients for whom the CROSS regimen, which has fewer side effects and is potentially organ-sparing, is still highly effective. Furthermore, the inclusion of the EDIC provides a data-driven basis for selecting advanced radiotherapy techniques, such as proton therapy, to minimize immune cell dose and potentially improve survival. References: [1] de Jong VMT, Moons KGM, Eijkemans MJC, Riley RD, Debray TPA. Developing more generalizable prediction models from pooled studies and large clustered data sets. Statistics in Medicine 2021;40:3533–59. https://doi.org/10.1002/sim.8981. [2] Xu C, Jin J-Y, Zhang M, Liu A, Wang J, Mohan R, et al. The Impact of the Effective Dose to Immune Cells on Lymphopenia and Survival of Esophageal Cancer after Chemoradiotherapy. Radiother Oncol 2020;146:180–6. https://doi.org/10.1016/j.radonc.2020.02.015. Keywords: nCRT, EDIC, Risk Stratification Digital Poster 753 Prognostic value of tumor regression after neoadjuvant chemoradiotherapy or chemotherapy in distal esophageal and GEJ adenocarcinoma: real- world data Solanche Jasmin Santillan 1 , Laura Gonzalez- Aguado 2 , Clara Rodrigo 2 , Ismael Macias 2 , Lina Candia 2 , Carme Ares 1 , Carlos Clavell 1 , Luisa Delgado 1 , Miriam Cuatrecasas 3 , Ivan Archilla 3 , Maite Rodrigo 3 , Carla Fuster-Anglada 3 , Dulce Momblan 4 , Victor Turrado- Rodriguez 4 , Javier Osorio 4 , M. Gloria Fernandez- Esparrach 5 , Josñe Ignacio Elizalde 6 , Alexandre Soler- Perromant 7 , Gerard Rafart 7 , Sebastian Casanueva 8 , Graciela Martinez-Palli 9 , Tamara Sauri 2 , Carles Conill 1 , Tanny Barreto-Zambrano 1 , Meritxell Mollà 1 1 Radiation Oncology, Hospital Clínic of Barcelona, Barcelona, Spain. 2 Medical Oncology, Hospital Clínic of Barcelona, Barcelona, Spain. 3 Pathology Department, Hospital Clínic of Barcelona, Barcelona, Spain. 4 Esophagogastric and Bariatric Surgery Unit, General and Digestive Surgery, Hospital Clínic of Barcelona, Barcelona, Spain. 5 Endoscopy Unit, Hospital Clínic of Barcelona, Barcelona, Spain. 6 Gastroenterology, Hospital Clínic of Barcelona, Barcelona, Spain. 7 Radiology, Hospital Clínic of Barcelona, Barcelona,
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