Abstract No. 163 Liver-Directed Therapy Modality-Specific Outcomes Controlling for Index Tumor Size in Early- to Intermediate-Stage Hepatocellular Carcinoma

The Barcelona Clinic Liver Cancer (BCLC) Staging and Treatment Algorithm recommends transarterial chemoembolization (TACE) and radio/microwave ablation (MWA) for non-resectable, early- to intermediate-stage (BCLC A-B) hepatocellular carcinoma (HCC). 90Yittrium (90Y) radioembolization is recommended as a secondary treatment pathway. As clinical data has become available, some centers have begun utilizing 90Y as a primary treatment option for BCLC A-B. This study uses retrospective data from multiple centers within a single health system to compare liver-directed therapy (LDT) outcomes among TACE, MWA, and 90Y after subgrouping based on primary target tumor diameter ≤ or > 3 cm. Retrospective, single system, multi-center study included treatment naïve, non-resectable HCC with BCLC A-B and ECOG 0-1 with underlying cirrhosis Child-Pugh (CP) A5–B9 that received liver-directed therapy (LDT) as a definitive treatment approach (n = 445, 2016-2023). LDT approaches included MWA, doxorubicin-eluting embolic TACE (DEE-TACE), and 90Y. Objective response (OR) was calculated after the first treatment cycle. Target time to retreatment (tTTR) and time to BCLC-C progression (TTP) were compared among treatment approaches. Subgrouping based on target tumor diameter yielded the cohorts: ≤ 3 cm–TACE (n = 94), MWA (n = 78), 90Y (n = 87) and > 3-cm–TACE (n = 54), 90Y (n = 132). In the ≤ 3-cm cohort, the OR was similar among treatment modalities (P = 0.053)–TACE (58/91), MWA (58/72), 90Y (65/82). Median tTTR (P < 0.001) was shorter for TACE (4 months) compared to MWA (43 months) or 90Y (31 months) and resulted in a higher 1 year retreatment frequency [TACE (68%), MWA (24%), 90Y (34%)]. However, TTP were similar (P = 0.194) with 2 year progression rates of–TACE (33%), MWA (19%), and 90Y (22%). In the > 3-cm cohort, there was a similar OR between treatments (P = 0.720) - TACE (33/51), 90Y (85/122). However, there was a significance difference in tTTR (P < 0.001) with TACE having a shorter median tTTR–TACE (2 months), 90Y (8 months). At 1 year after treatment, nearly all patients receiving TACE required retreatment to the target tumor–TACE (92%), 90Y (60%); however, TTP were similar (P = 0.633) with 2 year progression rates–TACE (48%), 90Y (54%). In this single system retrospective analysis, MWA and 90Y provided a more durable treatment response compared to TACE for HCC ≤ 3 cm. For HCC > 3 cm, 90Y also yielded a more durable treatment response compared to TACE.