ESTRO 2025 - Abstract Book

S1749

Clinical – Upper GI

ESTRO 2025

577

Digital Poster Patient-specific characteristics impact liver toxicity following liver SBRT

Austin Hopper 1 , Greg White 1 , Jona Hattangadi-Gluth 1 , Casey Bojechko 1 , Yevgeniy Vinogradskiy 2 , Vitali Moiseenko 1 1 Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, USA. 2 Radiation Oncology, Thomas Jefferson University, Philadelphia, USA Purpose/Objective: Outcomes data have shown that dose-volume constraints have limited predictive accuracy in predicting liver toxicity, suggesting that patient-specific characteristics must be considered. The purpose of this study was to establish if patient-specific characteristics, in particular, baseline Child-Pugh (CP) class, prior treatment, and history of cirrhosis influence liver toxicity following SBRT. Material/Methods: Toxicity and planning data were collected for 63 patients treated with gated SBRT. Patients had primary (32) or metastatic disease (31), 4D-CT was utilized for all patients. Gating was selected according to target or fiducial motion amplitude. Planning goals complied with HyTEC recommendations for mean liver dose (MLD) and maximum dose to spared 700 cc of normal liver. Dose ranged from 25-60 Gy in 3-5 fractions. GI toxicity and lab values were assessed pre-and 3 months post-SBRT according to CTCAE v5. CP scores were calculated pre-SBRT, 3- and 12-months post SBRT. Dosimetric parameters were tested for correlation with toxicity. Results: Median follow-up was 33 months; median overall survival was 30 months. Local control was 79.4%. Five (7.9%) patients developed G3+ liver enzyme toxicity, and 5 (7.9%) exhibited radiation-induced liver disease. CP class progression from A to B was seen in 7 (11.1%) patients, B-C in 4 (6.3%), A-C in 5 (7.9%). Six (9.5%) patients developed G3+ liver failure. Two G5 toxicities had pre-existing cirrhosis (NASH & A1AT deficiency). Median MLD for patients exhibiting G3+ liver enzyme toxicity tended to be higher (10.6 Gy vs 7.60 Gy, p=ns). No other dose-volume response was observed. Liver failure was significantly associated with pre-treatment CP class B/C compared to A (33% vs 4%, p<0.01). Baseline cirrhosis was significantly associated with CP class progression (p<0.01) at 3 months, even in well compensated CP class A patients. 3-month elevation of ALT, AST, or total bilirubin by >1 grade were significantly more frequent in patients who had received prior local therapy such as TACE/TARE/RFA (p = 0.0098). This trend was not seen in patients with prior surgical resection. Conclusion: HyTEC recommendations provide clinically acceptable liver sparing. However, multiple factors beyond dose-volume metrics influence the incidence of liver toxicity following SBRT, and more detailed guidelines accounting for patient and treatment-specific factors are needed. Elevated baseline CP class may increase the risk of long-term liver dysfunction, even with CP B7. Prior local ablative therapy may increase the risk of post-SBRT enzyme toxicity but was not seen to influence rates of severe long-term sequelae.

Keywords: Liver SBRT, toxicity

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Digital Poster Retrospective Analysis of Definitive Chemo-Radiotherapy for Oesophageal Carcinoma with Carboplatin and Paclitaxel Hammad Hammad, Michelle Mascarenhas, Romy Ni Chleirigh, Lorren Sweeney, Amy Jackson, Joachim Chan, Chinnamani Eswar