Efficacy of microwave ablation for intrahepatic cholangiocarcinoma: a systematic review and meta-analysis.

Background: Data on overall survival (OS) and progression-free survival (PFS) after microwave ablation (MWA) for intrahepatic cholangiocarcinoma (ICC) are scarce. We conducted a systematic review of the safety and efficacy of MWA for ICC.

Methods: The PubMed, Embase, Web of Science, and Cochrane Library databases were searched for studies reporting the outcomes of MWA for ICC. Meta-analyses of the pooled OS, PFS, technical success, technical efficacy, and complication rates were conducted. Pooled hazard ratios (HRs) of common variables were calculated to identify the factors associated with OS.

Results: The analysis encompassed 168 entries, among which 8 observational studies comprising 
423 patients were deemed eligible. The pooled results were as follows: The median OS was 22.0 months [95% confidence interval (CI): 15.1-28.9], with the 1-, 3-, and 5-year OS rates being 83.7% (95% CI: 
75.8-91.6%), 51.0% (95% CI: 41.1-60.9%), and 33.3% (95% CI: 14.1-52.4%), respectively. The median PFS was 12.5 months (95% CI: 8.3-16.7), and the 1-year PFS rate was 61.2% (95% CI: 36.5-85.9%). The technical success, technical efficacy, and major complication rates were 100% (95% CI: 99.5-100%), 99% (95% CI: 92.1-100%), and 2.8% (95% CI: 1.1-5.2%), respectively. A cancer antigen 19-9 (CA 19-9) level >37 U/mL was associated with a shorter OS (HR =1.4; 95% CI: 1.2-1.7; P=0.001).

Conclusions: MWA is a safe and effective alternative to chemotherapy, radiotherapy, and radiofrequency ablation (RFA) treatments, especially for patients with a CA 19-9 level ≤37 U/mL, and potentially has advantages over RFA. However, further studies are required to validate these findings.