Abstract No. 151 ▪ FEATURED ABSTRACT Update on the Use of Ultrasound Microbubble Destruction for Improving Radioembolization Therapy of Hepatocellular Carcinoma

This is an update on an ongoing single-site open-label randomized trial characterizing the ability of ultrasound microbubble destruction (USMD) in improving HCC response to TARE. Patients are assigned to the experimental tract of USMD + TARE or TARE alone. Patients in the experimental arm undergo contrast-enhanced ultrasound (CEUS) with USMD at 1-6 hours post-radioembolization and again at 7 and 14 days; the control group undergoes radioembolization with standard follow-up imaging surveillance. Response to treatment is evaluated using the modified response evaluation criteria in solid tumors (mRECIST) at 2-8 months post-treatment by two experienced radiologists blinded to the study. This is an update on 84 patients in the study with target enrollment of 104 patients. Demographic information of the initial cohort showed an average age of 68.5 years, 70% male, 88% with Child-Pugh A liver disease. Five patients withdrew from the study and one was lost to follow-up. Of the remaining 78 patients, 40 were in the control arm and 38 in the experimental arm. Initial median tumor size was similar between both control (33 mm, IQR 21-49 mm) and experiment arms (34 mm, IQR 23-42 mm). Within the control arm, 15 (37.5%) had stable disease (SD) and 25 (62.5%) had partial response (PR)/complete response (CR) at follow-up. Within the experimental arm, two had SD (5.3%) and 36 PR/CR (95%). Fisher's exact test analysis demonstrates statistically significant difference in outcomes between control and experimental arm (p = 0.002). There were 3 adverse events in the control arm and 12 adverse events in the experimental arm, none directly attributable to the ultrasound contrast agent. Data suggest that USMD is a well-tolerated technique that potentiates the effects of Y90 radioembolization for the treatment of HCC. The trial is ongoing and is expected to complete enrollment by the end of 2023.