Microwave ablation compared with hepatic resection for the treatment of hepatocellular carcinoma and liver metastases: a systematic review and meta-analysis

Abstract

Background: Hepatic resection (HR) is the gold standard liver cancer treatment, but few patients are eligible due to comorbidities or tumor location. Microwave ablation (MWA) is an important complementary liver cancer treatment to HR. This systematic review compared MWA with HR for liver cancer treatment.

Methods: A systematic search of MEDLINE, EMBASE, and CENTRAL was conducted for randomized and observational studies published from 2006 onwards. The primary outcome was local tumor recurrence (LTR), and a random effects model was used for meta-analyses.

Results: Of the 1845 studies identified, 1 randomized and 15 observational studies met the inclusion criteria. LTR was significantly increased with MWA versus HR (risk ratio (RR) = 2.49; P = 0.016). In secondary measures, HR provided significantly higher 3- and 5-year overall survival (RR = 0.94; P = 0.03 and RR = 0.88; P = 0.01, respectively) and 3-year disease-free survival (RR = 0.78; P = 0.009). MWA exhibited significantly shorter length of stay (weighted mean difference (WMD) = - 6.16 days; P < 0.001) and operative time (WMD = - 58.69 min; P < 0.001), less intraoperative blood loss (WMD = - 189.09 mL; P = 0.006), and fewer complications than HR (RR = 0.31; P < 0.001). When MWA was combined with HR and compared with either modality alone, complications and blood loss were significantly lower with the combination treatment; however, there were no differences in other outcomes. Subgroup and sensitivity analyses were generally aligned with the main results.

Conclusions: MWA can be an effective and safe alternative to HR in patients/tumors that are not amenable to resection. More randomized and economic studies should be performed that compare the two treatments, especially to determine the target population that benefits most from MWA.

Keywords: Hepatic resection; Hepatocellular carcinoma; Meta-analysis; Microwave ablation.

Fig. 1

PRISMA flow diagram

Fig. 2

Forest plot of random effects meta-analysis results for LTR. Overall P = 0.016, stratified by RCTs (P = 0.15) versus observational studies (P = 0.027)

Fig. 3

Weighted 1-, 3-, and 5-year overall survival and disease-free survival for MWA and HR. The error bars represent the 95% CIs for each estimate. Abbreviations: CI, confidence interval; DFS, disease-free survival; HR, hepatic resection; MWA, microwave ablation; OS, overall survival

Fig. 4

Summary of secondary analyses. Abbreviations: DFS, disease-free survival; EHM, extrahepatic metastases; HR, hepatic resection; IDL, intrahepatic de novo lesions; MWA, microwave ablation; OS, overall survival; RR, risk ratio; WMD, weighted mean difference

Fig. 5

Funnel plot assessing publication bias for LTR in eight studies. The red dot indicates the RCT. Abbreviations: HR, hepatic resection; MWA, microwave ablation

Fig. 6

Results comparison for RFA vs. HR meta-analyses [31, 32] with current study for a categorical and b continuous outcomes. *Feng, 2015 reported recurrence-free survival, where DFS was reported by the current study. †The ORs for complications have been inverted so that the favored treatment labels agree with those for the survival outcomes. ORs were calculated for the current study (MWA vs. HR) for comparability with outcome measures from Feng, 2015. Abbreviations: DFS, disease-free survival; HR, hepatic resection; MWA, microwave ablation; OR, odds ratio; OS, overall survival; RFA, radiofrequency ablation; RFS; recurrence-free survival; WMD, weighted mean difference

Fig. 7

Quality assessment of the Xu 2015 RCT