Microwave Thermosphere Ablation Versus Radiofrequency Ablation in Hepatocellular Carcinoma: Optimizing Treatment Strategies for Tumor Size and Malignancy Grade.

Aim: The next-generation microwave thermosphere ablation (MTA) system was developed to overcome the limitations of conventional microwave ablation. However, the comparative oncologic efficacy of MTA versus radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) remains uncertain. This study aimed to evaluate the oncologic benefits of MTA.

Methods: A retrospective analysis was conducted on 310 patients with primary HCC meeting the Milan criteria, treated with either RFA (n = 71) or MTA (n = 239). Metastatic recurrence was defined as ≥ 4 intrahepatic recurrences suggestive of intrahepatic metastases, extrahepatic metastases, or dissemination. High-grade malignant HCC was classified as non-single nodular type or alpha-fetoprotein lens culinaris-agglutinin reactive fraction (AFP-L3) positive (> 10%).

Results: MTA was associated with significantly lower metastatic recurrence and HCC-specific mortality rates compared to RFA. Multivariate analysis identified the ablation method as an independent factor contributing to metastatic recurrence and HCC mortality. Among patients with HCC ≤ 2 cm, metastatic recurrence rates did not differ significantly between groups. However, for HCC > 2 cm, MTA showed significantly lower metastatic recurrence rates than RFA. In non-single nodular or AFP-L3-positive HCC, metastatic recurrence rates were similar between groups, whereas in single nodular or AFP-L3-negative HCC, MTA significantly reduced metastatic recurrence.

Conclusions: MTA provides superior oncologic outcomes compared to RFA, particularly in reducing HCC-specific mortality and metastatic recurrence rates. MTA should be considered the preferred ablative therapy for select HCC patients, in particular those with tumors > 2 cm or those without high-grade malignancy.