Microwave Ablation Versus Radiofrequency Ablation As Bridge Therapy In Potentially Transplantable Patients With Hepatocellular Carcinoma:a Propensity Score-matched Study

Background:Hepatocellular carcinoma(HCC)is the fifth most common cancer and the third leading cause of cancer-related death in the world.One of the best treatment options for HCC patients with early-stage tumors is liver transplantation(LT).LT candidates for HCC patients are most commonly used by Milan criteria.Once recurrence beyond the Milan criteria(RBM),HCC patients will have to drop out of the transplant list.Therefore,in order to prevent the progression of RBM and to confer the best chance for survival,bridge therapy has been widely used in LT candidates with HCC.As an effective and safe way of bridge therapy,radiofrequency ablation(RFA)has the advantage of providing potential radical treatment during the waiting period.After RFA,some HCC patients will still develop RBM,which affects the survival prognosis.Compared with RFA,microwave ablation(MWA)is more effective in larger ablation areas and has fewer concerns for the heat sink effect by applying higher temperatures in a shorter time.Recently,the efficacy of MWA as bridge therapy for HCC patients with Milan criteria has been gradually confirmed.However,compared with RFA,the efficacy of MWA as bridge therapy for early HCC is still unclear,which requires further research.Aims:We aimed to compare the efficacy in potentially transplantable patients with HCC receiving MWA or RFA as bridge therapy by using propensity score matching(PSM).Methods:From January 2010 to December 2019,a total of 307 potentially transplantable patients with single HCC≤3cm who initially received MWA(n=82)or RFA(n=225)were included.We built a new PSM cohort(n=212)comprising 75 patients in the MWA group and 137 patients in the RFA group,according to the gender,age,etiology,tumor size and grade,aspartate transaminase,alanine aminotransferase,serum alpha-fetoprotein(AFP)and grade,antiviral treatment,presence of liver cirrhosis,presence of portal hypertension,Child-Pugh grade,and model for end-stage liver disease(MELD)score by using PSM.The RBM,recurrence-free survival(RFS),overall survival(OS),complications and hospital stays between the two groups in the total cohort and the PSM cohort were analyzed.Competing risks cox regression was used to identify prognostic factors of RBM,RFS,and OS.Results:In the total cohort,the 1-,3-,and 5-year RBM rates were 6.3%,16.9%,and 35.4%in the MWA group(n=82),and 6.8%,22.2%,and 34.6%in the RFA group(n=225),respectively,with no significant difference(p=0.625).Neither corresponding RFS rates(68.3%,43.3%,and 28.6%vs.71.6%,48.0%,and 33.0%,p=0.873)nor OS rates(97.5%,87.7%,and 76.5%vs.97.7%,86.3%and 69.2%,p=0.218)for 1-,3-and 5-years were significantly different between the two groups.In the PSM cohort,the 1-,3-,and 5-year RBM rates were 6.8%,18.3%,and 39.3%in the MWA group(n=75),and 7.4%,18.5%,and 27.7%in the RFA group(n=137),respectively(p=0.386).The 1-,3-,and 5-year RFS rates were 66.7%,39.2%,and 21.4%in the MWA group,and 70.8%,47.0%,and 34.7%in the RFA group,respectively(p=0.310).The 1-,3-,and 5-year OS rates were 97.3%,88.0%,and 75.4%in the MWA group,and 97.8%,85.1%,and 70.7%in the RFA group,respectively(p=0.384).There was also no significant difference above between the two groups.In the PSM cohort,AFP(HR,1.001;95%CI,1.000-1.001;p=0.004)was an independent prognostic factor on the multivariate analysis for RBM.The MWA group showed more frequent major complications(21.4%vs.7.1%,p=0.004)and longer hospital stays(4 days vs.2 days,p<0.001)compared with the RFA group.Conclusion:Compared with RFA,MWA has the similar efficacy as bridge therapy for HCC patients.Furthermore,LT should be considered early in the treatment pathway for potentially transplantable patients at greater risk of RBM.