ESTRO 2025 - Abstract Book

S1816

Clinical – Upper GI

ESTRO 2025

3141

Digital Poster A single centre experience of hepatocellular carcinoma (HCC) liver SABR: Clinical audit, outcomes and evaluation of local relapse pattern. Carmen Cañadillas Navero 1 , Luis Aznar Garcia 2 1 Radiation Oncologyst, HNSS, Complejo Asistencial de Salamanca, Ávila, Spain. 2 Clinical Oncologyst, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom Purpose/Objective: Our objective is to assess adherence to standard clinical practice for treatment, follow-up, and clinical outcomes of patients treated with SABR for liver HCC at NUH and to analyse relapse pattern in those who developed local disease progression post-SABR to ascertain whether relapse was within an ablative dose volume Material/Methods: Standard clinical practice lays over recommendations from main UK guidelines. Patients presenting local tumor progression had dosimetry assessment performed. Post-SABR diagnostic imaging confirming disease progression was fused with SABR radiotherapy planning CT (RTCT) scan to ascertain whether site of relapse was within an ablative dose volume (ADV). Results: 14 patients were included. Most patients were males (n=13; 92.8%) and median patient age was 71 years (range 66 74y). All HCCs tumours (n=14) were <5cm in greatest dimension and at the time of diagnosis. All patients presented ECOG-PS 0-1, 86% of patients had Child-Pug A liver cirrhosis and 14% Child-Pug B, and life expectancy was more than 6 months for 100% of the patients before SABR treatment. None of the patients received previous upper abdomen radiotherapy treatment. RTCT scans were performed with active breathing control (ABC) in exhale for all patients. In 71% of the patients the prescription dose was of 50 Gy delivered in 5 fractions every-other-day. The other 29% received 40Gy delivered in 5 fractions. 64.3% (n=9) of patients had their response to SABR assessed radiologically with liver CT/MRI imaging at least 3 months following completion of treatment. The remainder were lost to follow-up and were not included in analysis of treatment response. Median follow-up was 9 months (3,4 19,5). 77,7% (n=5) had sustained local tumour control following SABR with no radiological progression at any stage after. Median survival post-SABR for whole cohort was 9,86 months (IQR 9,8-21,4) with a 1-year overall survival rate of 85,7% and 1-year local control rate of 78,5%. 3 patients developed local progression (LP). Median time to LP was 21 months. 2 out of 3 patients presenting LP needed a second SABR. 1 patient presented in-field persistence disease and 2 presented marginal relapse within the ADV. Conclusion: For all patients the standard clinical practice was fulfilled. Increased/more accurate clinical target volumes (all patients had HpB Radiology peer review) should be considered to prevent marginal relapse as well as inaccuracy on ABC system.

Keywords: HCC, SABR