S1093
Clinical – Upper GI
ESTRO 2026
Digital Poster Highlight 3146 Dose escalation of definitive chemoradiotherapy in Asian patients with esophageal cancer: a retrospective cohort study Shuo-Fu Chen, Pin-I Huang, Yu-Ming Liu, Tzu-Yu Lai Heavy Particles & Radiation Oncology, Taipei Veterans General Hospital, Taipei, Taiwan Purpose/Objective: The benefit of dose escalation beyond 50.4 Gy in definitive chemoradiotherapy (CCRT) for esophageal cancer is controversial, with negative randomized trials from Western populations. Given the differing disease characteristics in Asian patients, this large retrospective study aims to evaluate the clinical outcomes of dose escalation in an Asian patient cohort. Material/Methods: We reviewed 997 Asian adult patients with newly diagnosed esophageal cancer who received definitive chemoradiotherapy at a single institution between 2007 and 2024. Patients were excluded for the following: metastatic disease, prior/synchronous malignancies, non-standard or incomplete CCRT (dose<45 Gy, split-course, brachytherapy, omission of chemotherapy), confounding treatments (concurrent or adjuvant immunotherapy), non-invasive disease (carcinoma in situ) and insufficient follow-up (<30 days). Patients were stratified into a standard-dose (<50.4 Gy) or a high-dose ( ≧ 50.4 Gy to the primary tumor) group. Inverse probability of treatment weighting (IPTW) was used to balance baseline characteristics. Primary outcomes included locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS). Results: Among the 400 eligible patients (280 high-dose, 120 standard-dose), the median follow-up was 350 days (IQR 308-419). Baseline characteristics were well- balanced after IPTW (Table 1). In IPTW-weighted analysis, the high-dose group exhibited significantly improved LRFS compared to the standard-dose group (HR: 0.68, 95% CI: 0.51-0.90, P = 0.006; Figure 1A). The 1-year LRFS was 37.4% (95% CI: 31.3-44.5%) in the high-dose group and 19.5% (95% CI: 12.0-31.7%) in the standard-dose group. Moreover, the high-dose group exhibited superior PFS (HR: 0.66, 95% CI: 0.50-0.87, P = 0.004; Figure 1B) and OS (HR: 0.66, 95% CI: 0.49-0.89, P = 0.006; Figure 1C) compared to the standard-dose group. On multivariable Cox regression analysis, higher radiation dose (HR 0.68, 95% CI 0.51-0.90, p=0.006) was associated with decreased risk of progression, while T4 stage (HR 2.23, p=0.012) and betel nut use (HR 1.32, p=0.027) were associated with increased risk.
recipe. No internal fiducials were implanted. Radiation was delivered via an intensity-modulated radiation therapy/volumetric modulated arc therapy approach using a Varian TrueBeam linear accelerator. Online image-guided target location was performed using an automated Varian on-board cone-beam computed tomography matching system. Results: A total of 28 targets were diagnosed with HCC using LI- RADS v2018 criteria, and four by liver biopsy between 2016 and 2024. Patients were predominantly men (69%), with a mean age of 81(±1, SE) years. Forty percent of patients had a Charlson Comorbidity Index ≥ 5. Most had preserved liver function: 97% were classified as Child-Pugh A, and 3% as B, BCLC stage was 0 (6.3%), A (81.3%) and B (12.5%), and the mean MELD score was 8.5(±0.4). Two targets were treated simultaneously in 31% of cases; in a 11% of cases, the target volume involved two distinct nodules. In 90% of treatments, EBH could be performed, while remaining targets were treated using free respiration. The mean dose per target was 45.6(±0.6; range, 40-60) Gy administered in three (81%) or five (19%) fractions. The mean PTV was 33(±5)-mL (equivalent to sphere = 38- mm). LC was assessed every 3-months using LI-RADS radiation treatment response assessment v2024 and (m)RECIST criteria. Mean follow-up was 17.3(±2) months. Twenty targets have been followed-up for more than 12 months and showed LC; of the remaining 12 targets with a less than 12 months period, two patients still showed viable tumor at 2.7 and 7 months after SBRT. Actuarial LC per target was 93(±0.5)% at 40 months, with an estimated mean for LC time of 41 months (±1.8; 37.3–44.6, 95% CI). No toxicity ≥ grade 2 was reported. Conclusion: SBRT is a safe and highly effective treatment with minimal toxicity for HCC. References: EASL Clinical Practice Guidelines on the management of hepatocellular carcinoma. Journal of Hepatology, February 2025. vol. 82 j 315–374Kim H, Kim B, Son SH, Jang JW, Sung PS, Choi JI, Kim S, Oh JS, Chun HJ. Evaluation of the LI-RADS radiation treatment response assessment v2024 in comparison with the modified RECIST. Eur Radiol. 2025 Jun 5. doi: 10.1007/s00330-025-11730-x. American College of Radiology (ACR). LI-RADS® CT/MRI Radiation Treatment Response Assessment (TRA) v2024 Core. Reston, VA: ACR; 2024 Keywords: Hepatocarcinoma (HCC), SBRT, SABR
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