The safety and efficacy of selective internal radiation therapy for hepatocellular carcinoma: A retrospective study in China.

e16311 Background: The significance of selective internal radiation therapy with yttrium-90 resin microspheres ( 90 Y-SIRT) is widely acknowledged in the management of hepatocellular carcinoma (HCC), especially the application in advanced HCCs, which has been launched in China in 2022. The purpose of this study was to evaluate the efficacy and safety of 90 Y-SIRT in Chinese patients. Methods: HCC patients treated with 90 Y-SIRT between June 2022 and Sep 2024 in our center were included in this study. Patients’ response to 90 Y-SIRT were recorded. The primary endpoint was the objective response rate (ORR), and the secondary point were disease control rate (DCR), downstaging rate, which were measured by modified Response Evaluation Criteria in Solid Tumors Criteria (mRECIST). Side effects were also recorded, which were evaluated via the Common Terminology Criteria for Adverse Events Version 5.0. Results: In this retrospective study, a total of 33 patients with hepatocellular carcinoma (HCC) underwent 90 Y-SIRT and were followed for more than 3 months. The median age of the cohort was 56 years (IQR, 50-61 years) and 87.9% were male. The majority of patients (81.8%) had HBV-related HCC, and 93.9% had an ECOG performance status of 0. Portal vein tumour thrombus was present in 39.39% of patients, extrahepatic metastases in 36.36%, and bilobar liver lesions in 63.6%. The BCLC stages were distributed as 18.2% A (n = 6), 36.4% B (n = 12), and 45.5% C (n = 15). Patients received a median 90Y dose of 1.6 GBq (IQR, 1.0-2.8 GBq) to a target tissue dose of 244 Gy (IQR, 189-300 Gy), often in combination with systemic treatment (75.8%). The median follow-up duration was 13.7 months (IQR, 9.2-17.2 months).The overall objective response rate (ORR) was 87.8%, and the disease control rate (DCR) was 90.9%. Specifically, Group A had an ORR of 100% (6/6), Group B had 91.67% (11/12), and Group C was 80% (12/15). Patients with bilobar lesions had an ORR of 85.71% (18/21). Notably, 76.9% of patients (20/26) were successfully downstaged, with 11 patients in Group C undergoing surgery. The median time to surgery was 7 months (IQR, 4-7.5). No patients experienced Grade 3 or higher adverse events, with mild fever, abdominal pain, and fatigue being the most common adverse events. Conclusions: In this retrospective study, 90 Y-SIRT exhibited notable efficacy and safety in Chinese HCC patients, achieving an impressive objective response rate (ORR) of and a substantial downstaging rate.