Chemoembolization Plus Microwave Ablation vs Chemoembolization Alone in Unresectable Hepatocellular Carcinoma Beyond the Milan Criteria: A Propensity Scoring Matching Study

PURPOSE: Transarterial chemoembolization (TACE) is recommended in patients with unresectable HCC beyond the Milan criteria (MC). However, the long-term efficacy of TACE remains unsatisfactory. Percutaneous microwave ablation (MWA) is a curative therapy for early-stage HCC that provides better local tumor control than TACE; however, MWA is limited for large or multifocal lesions. We aimed to compare treatment efficacy and downstaging rate following combined TACE-MWA and TACE alone in patients with unresectable HCC beyond the MC. PATIENTS AND METHODS: Patients with unresectable HCC beyond the MC who underwent either TACE-MWA (n=91) or TACE alone (n=140) at four medical institutions were included. Potential influencing factors on overall survival (OS) and progression-free survival (PFS) were included in the Cox regression analysis. Propensity-score matching of patients treated with TACE-MWA and TACE alone was performed. Differences in OS and PFS were compared with the Log rank test. Patients who met the University of California, San Francisco criteria were eligible for assessment of the probability of downstaging within the MC. Downstaging rate was compared between the two groups. RESULTS: In multivariate analysis, treatment with TACE alone was an independent predictor of poor PFS (P=0.011) and OS (P<0.001). Both PFS (P=0.043) and OS (P=0.002) were significantly higher in patients treated with TACE-MWA than those treated with TACE alone. The downstaging rate was higher in patients treated with TACE-MWA than those treated with TACE alone (P=0.039). CONCLUSION: Compared with TACE alone, TACE-MWA may offer a survival benefit in terms of OS and PFS in HCC patients beyond the MC. Additionally, TACE-MWA may provide higher probability of downstaging within the MC than TACE alone, thereby increasing the possibility of liver transplantation.