Abstract No. 79 Comparison of 90Y Radioembolization Outcomes for Hepatocellular Carcinoma (HCC) in TACE-Refractory (T-REF) vs Treatment Naïve (TN) Patients in the RESiN Registry (NCT: 02685631)

To determine whether T-REF HCC patients undergoing resin 90Y following TACE have poorer overall survival (OS), imaging response, and toxicity than TN patients. In this prospective, observational study, 321 HCC patients were T-REF (n = 117, 36%) or TN (n = 204, 64%). Patients who had prior ablation, surgery, or chemotherapy were excluded. Overall and progression-free survival (OS/PFS) outcomes were measured by follow-up and assessed using Kaplan-Meier analysis. Six-month imaging response was evaluated using modified Response Evaluation Criteria in Solid Tumors (mRECIST). Six-month toxicities were reported using Common Terminology Criteria for Adverse Events v5. Baseline demographics are reported in the TABLE. The T-REF group had more bilobar (P = 0.03) and multifocal (< 0.001) disease. The TN group was older (P = 0.03), with higher incidence of vascular invasion (P = 0.04) and larger index tumor diameter (P = 0.001). The sum of tumor diameters was not different between groups (P = 0.06). Median delivered 90Y activity was similar for T-REF (1.2 GBq: 95% CI: 1-1.6) and TN (1.2 GBq; 95% CI: 0.9-1.6 GBq). The median OS for T-REF was 19.8 months (95% CI: 15.4-25.2) and was 21.5 months (95% CI: 14.9-29.9) for TN vs (P = 0.9). Median PFS for T-REF was 8.4 months (95% CI: 6.2-12.1) and 13.0 months (95% CI: 10.8-17.7) for TN (P = 0.006). Six-month imaging was available in 67/117 T-REF and 118/204 TN patients. Partial or complete response was seen in 30/67 (45%) of the T-REF and 68/118 (58%) TN patients (P = 0.2). Six-month toxicities were available in 88/117 (75%) T-REF and 167/204 (82%) TN patients. Attributable grade 3 or greater albumin and bilirubin toxicities were present in 5/88 (6%) T-REF vs. 7/167 (4%) TN (P = 0.2) and 12/87 (14%) T-REF vs 16/204 (8%) TN (P = 0.04) patients. OS of T-REF patients is similar to TN, but PFS is shorter with similar imaging response at 6 months. Radioembolization is a reasonable treatment option for TACE refractory HCC.