ESTRO 2025 - Abstract Book

S1772

Clinical – Upper GI

ESTRO 2025

Conclusion: Daily CT and MR-guided CISR is feasible in the liver, but using daily imaging for OOA seems significantly less beneficial than DOA. Since MRI offers superior target detection, we are currently establishing a clinical MR-guided DOA workflow.

Keywords: liver cancer, carbon ions, online adaptation

References: 1. Gkika et al., Excellent local control and tolerance profile after stereotactic body radiotherapy of advanced hepatocellular carcinoma. Radiat Oncol 2017. 2. Kim et al., Proton beam radiotherapy vs. radiofrequency ablation for recurrent hepatocellular carcinoma: A randomized phase III trial. J Hepatol 2021. 3. Méndez Romero et al., Transarterial Chemoembolization With Drug-Eluting Beads Versus Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: Outcomes From a Multicenter, Randomized, Phase 2 Trial (the TRENDY Trial). Int J Radiat Oncol Biol Phys 2023. 4. Hoegen-Saßmannshausen et al., Carbon ion radiotherapy of hepatocellular carcinoma provides excellent local control: The prospective phase I PROMETHEUS trial. JHEP Rep 2024.

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Digital Poster Feasibility and outcomes of patients with pancreatic cancer treated on the 1.5 MR-Linac in an Australian public hospital setting Miki Wada 1 , Richard Khor 1 , Morikatsu Wada 1 , Niall TebbuttNiall Tebbutt 2 , Vijayaragavan Muralidharan 3 , Mehrdad Nikfarjam 3 , Mark Tacey 1 , Brayden Geary 1 , Felicity Height 1 , Reza Alinaghi Zadeh 1 , Numan Kutaiba 4 , Sweet Ping Ng 1 1 Radiation Oncology, Austin Health, Melbourne, Australia. 2 Medical Oncology, Austin Health, Melbourne, Australia. 3 Hepato-Pancreato-Biliary and Liver Transplant Surgery, Austin Health, Melbourne, Australia. 4 Radiology, Austin Health, Melbourne, Australia Purpose/Objective: This study reviews the clinical and quality of life (QoL) outcomes of pancreatic cancer patients treated using a 1.5 Tesla (T) magnetic resonance linear accelerator (MRL) at a single institution in Melbourne, Australia. Material/Methods: Pancreatic cancer patients enrolled in the FIRM study who were treated with MRL between August 2021 and May 2024 were included. Acute toxicity was assessed weekly until the end of treatment then at 3-monthly intervals to 19 weeks post-radiotherapy commencement. QoL was evaluated at baseline, 3 months and 6 months using the EORTC QLQ-C30 questionnaires. Overall survival was assessed using Kaplan-Meier analysis. Results: 11 patients were included, with a mean age of 74 years at registration. Six patients were female. Four patients had an ECOG performance status of 0 and 1 respectively and three patients of 2. Three patients (27%) underwent excisional biopsy and six (55%) fine needle aspiration for confirmation of diagnosis. All patients had unresectable pancreatic carcinoma. One patient received concurrent chemotherapy and one patient received re-irradiation of the same primary site. The mean total dose received was 44.6Gy over 4.8 fractions, with a mean dose per fraction 10.4Gy. Treatment time per fraction was approximately 45 minutes using predominantly Adapt to Shape (ATS) function. Acute Grade 2 fatigue was reported in one patient (9%). All other acute toxicities (headache, nausea, diarrhoea, abdominal pain, dermatitis) were reported as Grade 0 or 1. No Grade 3 or higher acute toxicities were reported. QoL assessments revealed an increase in QLQ-C30 global health status at 3 months (mean difference [MD] +4.17