S1121
Clinical – Upper GI
ESTRO 2026
ASUGI, Trieste, Italy. 3 SC Radioterapia, Azienda Sanitaria Universitaria Udine ASUFC, Udine, Italy
Purpose/Objective: To investigate the correlation between local control and best radiologic response in patients (pts) treated with stereotactic body radiation therapy (SBRT) for liver metastases Material/Methods: We retrospectively analysed 23 liver metastases in 14 oligometastatic/oligoprogressive pts treated with SBRT between May 2020 and January 2023 at our institution. A coupled markers are implanted near the liver tumor or inside under ultrasound guidance to allow monitoring the tumour motion during the treatment. A support pillow vacuum was forming for CT scan treatment planning and a new CT scan after contrast medium administration was conducted in the same day and with same supports to ensure better image fusion. SBRT was delivered by VMAT-IGRT. Follow-up was performed with a CT or FDG/PET-CT every three months. The primary endpoint was evaluating best response in term of complete response (CR), partial response (PR), stabile disease (SD) and progression disease (PD), according to RECIST 1.1 classification system, for local control (LC). Secondary endpoints were evaluating overall survival (OS) and progression free survival (PFS). Results: Median age was 71 years (range, 64-83 years). Most common primary tumour was gastrointestinal(GI) adenocarcinoma(82.6%). Most common SBRT dose was 40 Gy/5 daily fractions(fr), 35 Gy/5 fr was administered in one pt with 3 lesions treated at the same time. The median survival was 46 months (CI 95% 40.1-51.8) and the actuarial 1-year, 3-year and 4- year OS were 95%, 73% and 43.5% respectively. Six- months and 1-year LC was 78.3% and 65.2% respectively. 6-months, 1-year, and 2-year PFS were 73.9%, 46.4% and 13.2% respectively. Best radiological response after SBRT was found at median time of 7months and revealed CR in 6 lesions (26%) at median time of 9months, PR in 10 lesions (43.4%) at median time of 8months, SD in 4 lesions (17.3%) at median time of 4months and PD in 3 lesions (13%) at median time of 4months. The 1-year LC for CR vs PR vs SD vs PD were 50%, 26.7%, 25% and 0% respectively (p-value <0.01, CI 95% 1.49-7.44) (fig.1). At 1-year and 3-year, OS for CR vs PR vs SD vs PD was also significant with a p-value <0.01. No toxicity was observed in acute or late toxicity. Fig.2.
Conclusion: SBRT appears to be a safe treatment for liver metastases, providing an important local control rateand the best radiological response seems to be an important prognostic factor distinguishing between slowly local progressing patients and rapidly progressing patients Keywords: LIVER, SBRT, RECIST Digital Poster 4794 Predictive model for SBRT target coverage in unresectable intrahepatic cholangiocarcinoma to support clinical decision-making Hangrui Zhu 1 , Linda Chen 1 , Thomas Zwaan 2 , Wilhelm den Toom 1 , Claudia Schuurhuizen 1 , Ben Heijmen 1 , Bas Groot Koerkamp 2 , Linda Rossi 1 , Erik van Werkhoven 1 , Alejandra Mendez Romero 1 1 Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands. 2 Surgery, Erasmus MC Cancer Institute, Rotterdam, Netherlands
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