Radioembolization for Hepatocellular Carcinoma with Localized Portal Vein Tumor Thrombosis in Patients with Preserved Liver Function

Purpose: To evaluate the clinical outcomes of radioembolization and the impact of dosimetry for hepatocellular carcinoma (HCC) with localized portal vein tumor thrombosis (PVTT) in patients with preserved liver function
 

Materials and Methods: Forty-eight patients with unilobar HCC and PVTT confined to the tumor-bearing lobe were treated with radioembolization using glass microspheres at a single institution between January 2016 and December 2023. Yttrium-90 glass microspheres were initially prescribed to deliver approximately 120 Gy to the perfused volume for the first two years. Afterward, treatment approaches were stratified based on the level of PVTT: radiation segmentectomy or modified radiation lobectomy for HCC with subsegmental to sectional PVTT (Vp1-2), and lobar treatment for HCC with lobar PVTT (Vp3). Tumor responses were assessed using mRECIST criteria. Survival outcomes and prognostic factors were analyzed, and a cut-off dose for significantly prolonged overall survival (OS) was determined using the minimum p-value approach.

Results: The study included 21 patients with Vp1-2 PVTT (44%) and 27 patients with Vp3 PVTT (56%), with a mean tumor diameter of 7.1 ± 3.0 cm. Best tumor responses were as follows: complete response in 22 patients (46%), partial response in 18 patients (38%), stable disease in 5 patients (10%), and progressive disease in 3 patients (6%) according to mRECIST criteria. The median progression-free survival, hepatic progression-free survival, and OS were 8.5 months, 12.2 months, and 47.2 months, respectively. Adverse events of grade 3 or higher occurred in 16 patients (33%), with lymphocyte count decrease (17%) and anemia (10%) being the most common. The Univariate Cox proportional hazards analysis identified mean tumor absorbed dose (mTAD) (p = .031), PVTT level (p = .067), and largest tumor size (p = .027) as potential factors influencing survival. In the multivariate analysis, mTAD emerged as the only significant predictor of overall survival (OS) (p = .032; hazard ratio per 100 Gy = .862, 95% confidence interval = .753 to .988). A tumor absorbed dose of 586 Gy was identified as the threshold for prolonged OS (median OS: 21.9 months for mTAD ≤ 586 Gy vs. 49.5 months for mTAD > 586 Gy).

Conclusion: Radioembolization is both effective and safe for HCC with localized PVTT, and delivering a mTAD greater than 586 Gy may significantly improve OS.