Microwave ablation for peribiliary hepatocellular carcinoma: propensity score analyses of long-term outcomes.

OBJECTIVE To compare the long-term outcomes of MWA as the first-line treatment for HCC in peribiliary versus non-peribiliary locations using propensity score matching analysis. METHODS The study participants were recruited between April 2012 and October 2016. In total, 236 patients with HCC <5 cm who underwent ultrasonography-guided percutaneous MWA as the first-line treatment were enrolled. The patients were grouped into two according to tumor location: peribiliary (n = 74) and non-peribiliary (n = 162). The progression-free survival (PFS) and overall survival (OS) rates were compared before and after propensity score matching. Subgroup analyses were conducted for the peribiliary group according to the biliary grading. RESULTS Propensity score matching yielded 63 matched pairs of patients. In the two matched groups, cumulative PFS rates were 29.0% and 14.0% in the peribiliary group, and 51.0% and 31.0% in the non-peribiliary group at 3 and 5 years, respectively. Corresponding OS rates were 51.0% and 49.0% in the peribiliary group, and 77.0% and 70.0% in the non-peribiliary group at 3 and 5 years, respectively. In addition, there were significant differences in major complication rates between the two groups (25.7% vs 8.0%; p < .001). In contrast to peribiliary HCCs adjacent to the second-degree branches of intrahepatic bile duct (67.1 ± 5.2 months), subgroup analysis indicated that the mean OS was significantly lower in peribiliary HCCs adjacent to the first-degree branches (51.2 ± 7.5 months) (p = .015). CONCLUSION The application of MWA for peribiliary HCC leads to a higher rate of complications and worse long-term tumor control than for non-peribiliary HCC.KEY POINTSThe application of MWA for peribiliary HCC leads to a higher rate of complications than for non-peribiliary HCC.The application of MWA for peribiliary HCC leads to worse long-term tumor control than for non-peribiliary HCC. Abbreviations: Hepatocellular carcinoma (HCC); microwave ablation (MWA); α-fetoprotein (α-FP); local tumor progression (LTP); intrahepatic distal recurrence (IDR); progression-free survival (PFS); overall survival (OS).