Downstaging therapy of intermediate-stage hepatocellular carcinoma: microwave ablation vs. surgical resection

Background: Transarterial chemoembolization(TACE) is a potential downstaging therapeutic strategy for intermediate-stage hepatocellular carcinoma(HCC). However, therapeutic options following conversion therapy is still controversial. Purpose: This study aimed to compare the efficacy and safety of surgical resection(SR) and microwave ablation(MWA) following TACE based downstaging therapy for intermediate-stage HCC. Methods: From January 2008 to December 2021, a total of 2,125 consecutive patients with intermediate-stage HCC underwent initial TACE at seven hospitals were identified. Among them, 554 eligible HCC patients occurred objective response(OR) to TACE, who meet the tumor burden equivalence of early-stage disease. The propensity score matching(PSM) was applied to reduce selection bias. The overall survival(OS) and recurrence-free survival (RFS) were compared using the Kaplan-Meier method with the log-rank test. Independent risk factors for survival outcomes were identified through multivariable Cox analyses using forward stepwise regression. Results: After PSM 1:1, 152 patients in MWA group were matched with those in SR group. SR demonstrated comparable long-term survival outcomes (5-years OS rate, 85.3% vs 82.5% and 5-years RFS rate, 77.2% vs 75.0%) than MWA. Multivariate analyses showed that the factors that significantly affected the OS were Body Mass Index (hazard ratio[HR]:0.61;95% confidence interval [CI]: 0.37-0.82). Multivariate analyses showed that the interval between local-region treatment and TACE (HR:0.41; 95% CI: 0.24-0.67), HBV (HR: 0.32; 95% CI: 0.15-0.69) and systemic treatment (HR:0.44; 95% CI: 0.25-0.76) significantly affected the RFS. Conclusions: MWA might be acceptable as an alternative to SR in first-line TACE based downstaging therapeutic scheme for patients with intermediate-stage HCC.