Suppression of Local Tumor Progression in Perivascular Hepatocellular Carcinoma by Combination Therapy with Radiofrequency Ablation and Percutaneous Ethanol Injection: A Propensity Score Matching Analysis

Background and Aims: Radiofrequency ablation (RFA) has replaced percutaneous ethanol injection (PEI) as the treatment of choice for hepatocellular carcinoma (HCC); however, control of local tumor progression (LTP) remains a challenge in perivascular HCC. The aim of this study was to determine whether PEI added to RFA can reduce the LTP rate in perivascular HCC patients. Methods: We retrospectively analyzed 167 patients, with 197 newly diagnosed HCC nodules with peritumoral vessels, who underwent either RFA plus PEI or RFA monotherapy as the first-line treatment between June 2001 and April 2015. Ethanol was injected inside the tumor close to the peritumoral vessels in the combination therapy group. Patients were matched 1:1 according to their propensity scores to reduce selection bias; cumulative LTP was then analyzed using log-rank tests and Cox proportional hazard regression analyses. Results: The two matched groups comprised 62 tumors each. The overall median follow-up period was 34 months (range, 1–140 months). In the RFA plus PEI group, the cumulative LTP rates were 5.7%, 15.5%, and 20.4% at 1, 3, and 5 years, respectively; in the RFA monotherapy group, the rates were 13.2%, 32.0%, and 40.2%, respectively. The rates were significantly lower in the RFA plus PEI group (p = 0.032). Cox proportional hazard regression analysis showed that PEI combination treatment was significantly associated with a reduced risk of local HCC recurrence (hazard ratio, 0.44; 95% confidence interval, 0.19–0.93; p = 0.031). Discussion/Conclusion: The risk of LTP after RFA for perivascular HCC can be significantly reduced by injecting ethanol close to the peritumoral vessels.