S1073
Clinical – Upper GI
ESTRO 2026
Digital Poster 1428 Technical feasibility and safety of a novel fiducial marker in image guided stereotactic body radiotherapy for hepatocellular carcinoma. Febin Antony 1 , Jijoe John Vithayathil 2 , John Paul Puravath 1 , Varun Narayan 2 , Krishnapriya V 2 , Jomon Raphael C 1 , Sojan George K 3 , Anoob John KA 3 , Mathew Varghese K 1 , Rajkrishna B 1 , Jini M P 4 , Sunu Lazar Cyriac 5 1 Radiation Oncology, Amala Institute of Medical Sciences, Thrissur, India. 2 Radiology, Amala Institute of Medical Sciences, Thrissur, India. 3 Gastroenterology, Amala Institute of Medical Sciences, Thrissur, India. 4 Biostatistics, Amala Institute of Medical Sciences, Thrissur, India. 5 Medical Oncology, Amala Institute of Medical Sciences, Thrissur, India Purpose/Objective: Fiducial markers (FM) improve image registration accuracy during stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC), but conventional gold or embolization coil (EC) markers can produce significant imaging artefacts and increase treatment costs. To overcome these challenges, our department explored the off-label use of UltraClip (UC), a 3 mm coil shaped BioDur 108 marker, originally designed for breast localization, as a practical and cost-effective alternative. A departmental pilot study showed that UC with minimal artifact, achieved optimal image quality, making it a feasible alternative to EC, which caused higher artifacts. The present retrospective study aimed to evaluate the technical feasibility and safety of using UC as FM in patients with HCC who underwent image-guided liver SBRT. The primary objective was to determine the technical success rate (TSR), defined as completion of all five SBRT fractions using two UC for image-based alignment with translational setup error (SE) ≤ 3 mm on verification CBCT, while employing the UC + 5 mm matching protocol for registration. The secondary objective was to assess the migration rate (MR), defined as UC absence or displacement > 5 mm on follow-up CT compared with planning CT relative to the portal vein bifurcation. Material/Methods: This single-institution study included 20 patients diagnosed with HCC who underwent SBRT with deep inspiration breath-hold (DIBH) between March 2024 and June 2025, using two UC for image guidance. All patients were properly breathing-coached and treated with a breath-hold threshold of ≤ 2 mm. Baseline demographic, dosimetric, and imaging data were retrieved from institutional records and the Eclipse treatment-planning system. Technical performance was assessed from setup verification CBCTs, and UC migration was evaluated by comparing UC positions
Conclusion: We report on a real-world referral program for PBT, treating esophageal cancer with definitive PBT chemoradiation in a small cohort mostly of low ILD- GAP index patients. In limited follow up, radiation pneumonitis and cardiac toxicities were not observed, but treatment does have a detectable mortality rate. Since esophageal cancer has a three-year 50% overall survival (lower than ILD survival for severity generally corresponding to ILD-GAP index <4 [4]), offering the best likelihood of cancer control for ILD patients is supported. References: 1. Li et al. 2025, Int J Radiation Oncol Biol Phys PMID:40581332.2. Inoo et al. 2022, J Radiat Res PMID: 35589100.3. Carter et al. 2019, J Am Coll Cardiol PMID: 30846341.4. Ryerson et al. 2014, CHEST PMID: 24114524. Keywords: esophagus, protons, ILD
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