Purpose: To assess the feasibility and outcome of microwave ablation (MWA) of hepatic tumors in anatomically challenging locations.
Materials and methods: A total of 94 patients with 174 hepatic tumors referred for CT-guided MWA were included in this retrospective institutional review board-approved study. One hundred and twenty-five tumors (median size 17 mm, range 12-24 mm) with subcapsular location (n = 91) and/or in which a transpleural approach was applied (n = 53) were identified (group 1) and compared to tumors with a central intrahepatic location (group 2; n = 49, median size 19 mm, range 12-23 mm). Technical success, complications and local tumor progression (LTP) were evaluated. Risk factors were analyzed using univariate analysis, logistic regression and Kaplan-Meier curves (p < 0.05 deemed significant).
Results: Technical success was 100% in both groups. In group 1, complications occurred in n = 31 tumors (24.8%; pneumothorax n = 20; hematoma n = 11). Complications occurred significantly less often in group 2 (8.2%; n = 4 (hematoma); p = 0.011). There were no major complications. Transpleural approach and number of capsule punctures were identified as risk factors for complications (all p < 0.05). Median follow-up was 265 days. LTP was comparable between both groups (13.6 vs. 10.2%; p = 0.41). Use of hydrodissection was the only independent factor associated with LTP (p = 0.03, HR 3.29).
Conclusion: CT-guided hepatic MWA of subcapsular tumors and subdiaphragmatic tumors requiring a direct or transpleural approach is feasible with increased minor but not major complications. LTP did not differ significantly between both groups.
Keywords: Liver; Liver tumor; Microwave ablation; Subcapsular; Subdiaphragmatic.