3017 - Transarterial Chemoembolization plus Radiotherapy vs. Transarterial Chemoembolization Alone for Single Hepatocellular Carcinoma within BCLC Stage 0-A

H. I. Lee, S. M. Yoon, and J. Jung; Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of (South)

Purpose/Objective(s): This study aimed to evaluate the efficacy of transarterial chemoembolization (TACE) combined with radiotherapy (RT) versus TACE alone in patients with single hepatocellular carcinoma (HCC) within BCLC stage 0–A, and to identify patients who would benefit most from this combined treatment approach. Materials/

Methods: We retrospectively identified patients diagnosed with single HCC within BCLC stage 0–A and treated with first-line TACE between 2008 and 2018. Patients who received TACE followed by RT were compared with those receiving TACE alone for overall survival (OS) and progression-free survival (PFS). Subgroup analysis of 15 categorical variables was conducted to identify factors interacting with the effect of RT. Incorporating these factors, a TACE-RT stratification model was developed, categorizing patients into three groups with varying benefits from adding RT.
Results: Among the 1475 patients included, 244 (16.5%) patients received TACE followed by RT, and 1231 (83.5%) patients received TACE alone. There was no significant difference in patient characteristics between the two groups. With a median follow-up of 50.4 months, the TACE-RT group exhibited significantly higher OS rate (76.8% vs. 58.5% at 5 years; HR 2.00; p < 0.001) and PFS rate (37.5% vs. 16.8% at 5 years; HR 2.02; p < 0.001) compared with the TACE group. The TACE-RT group had higher OS across all subgroups, with outcomes influenced by tumor size over 4 cm, alpha-fetoprotein (AFP) levels above 100 ng/mL, and non-complete response (non-CR) to TACE. Based on these three parameters, the TACE-RT stratification model was established, categorizing patients into groups A, B, and C. The TACE-RT groups had significantly higher OS for group C patients (HR 3.23; p < 0.001), and to a lesser, but still significant, degree for group B (HR 1.90; p = 0.002). However, for group A patients, the increase in OS was not statistically significant (HR 1.47; p = 0.282). Similarly, the addition of RT improved PFS most significantly in group C (HR 2.66), with a decreasing benefit in groups B (HR 2.17) and A (HR 1.70); all groups showed statistical significance (p < 0.05). Additionally, within the TACE-RT group, a lower number of TACE sessions prior to RT was correlated with improved survival outcomes.
Conclusion: TACE plus RT was associated with a significantly higher OS and PFS compared with TACE alone in patients with single HCC within BCLC stage 0–A. Our TACE-RT stratification model suggests that in cases presenting one or more risk factors, such as tumor size over 4 cm, AFP levels above 100 ng/mL, or non-CR to TACE, the addition of RT following TACE may potentially enhance survival outcomes.

Abstract 3017 – Table 1: TACE-RT Stratification Model

Parameters (1 point for each)
Tumor size >4 cm
AFP >100 ng/mL
Non-CR to TACE
Stage	Treatment	N	Overall survival
			5-year (%)	HR	(95% CI)	p-value
A (0 points)	TACE-RT	36	81.4	-
	TACE	447	70.1	1.47	(0.73–3.00)	0.282
B (1 point)	TACE-RT	138	78.0	-
	TACE	485	61.6	1.90	(1.29–2.78)	0.002
C (=2 points)	TACE-RT	70	71.3	-
	TACE	299	35.6	3.23	(2.02–5.17)	<0.001