Percutaneous ablation in perivascular-HCC: impact of liver parenchyma and characteristics of vascular structures on the outcomes

Aim: Percutaneous radiofrequency ablation (RFA) is a standard treatment for small-HCC (<3 cm). However, some features such as proximity to intrahepatic vascular structures (perivascular location) seem to be related to short- and long-term outcomes. The aims of the study were to investigate the features related to ablation success and local tumor progression (LTP) in patients submitted to percutaneous ablation for perivascular-HCC. Materials and methods: From January 2010 to May 2021, 132 perivascular-HCC nodules ablated with US-guided single probe percutaneous RFA were retrospectively analyzed. Univariate analysis and multivariable Cox regression model were used to identify factors that were independently related to ablation success and LTP-free survival. Results: The overall ablation success rate was 71.9% (n=95). Morbidity and mortality rates were 4.0% and 0.0%. The features related to ablation success: nodule size (≤20 mm vs. >20 mm) (OR 2.442, p=0.031), major vascular structures diameter (3-5 mm vs ≥ 5 mm) (OR 2.167, p=0.037) and liver parenchyma (cirrhosis vs no-cirrhosis) (OR 2.373, p=0.033). The following features resulted independently related to better LTP-free survival: nodule size ≤20 mm (HR 2.802, p=0.003), proximity to glissonean pedicles (HR 1.677, p=0.028), and major vascular structure diameter <5 mm (HR 1.987, p=0.041). Conclusions: Perivascular location confirmed to be a difficult and unfavorable indication for percutaneous ablation for HCC nodules. However, perivascular nodules not suitable for surgery with low-risk features (size <20 mm, proximity to glissonian pedicles and vascular diameter <5 mm) may be treated with RFA with satisfactory outcomes.