Analysis of technical failure after 1,613 surgical microwave ablations: A propensity score-matched analysis

Microwave ablation is becoming increasingly common for the treatment of liver tumors. Despite numerous studies aimed at identifying risk factors for local recurrence after microwave ablation, a consensus on modifiable risk factors for failure remains elusive, partly because of the limited statistical power of these studies. This study investigated the incidence of technical failure after microwave ablation, encompassing both incomplete ablation and local recurrence, and aimed to identify modifiable factors that reduce technical failure.

This retrospective review included patients who underwent surgical microwave ablation at a high-volume institution between October 2006 and March 2023. Univariate analysis, multivariate analysis, and propensity score matching were performed to identify risk factors for technical failure.

A total of 1,613 surgical microwave ablations were performed on 3,035 tumors, with 226 instances (14% per procedure, 7.4% per tumor) of technical failure. Incomplete ablation occurred at a rate of 1.7% per tumor, whereas local recurrence was identified in 6.5% of ablations in per-tumor analysis. Body mass index >25 was significant for failure (odds ratio, 1.50; 95% confidence interval, 1.07-2.11; P < .05), suggesting that more difficult targeting may lead to increased technical failure rates. African American race (odds ratio, 1.62; 95% confidence interval, 1.16-2.27; P < .05), pre-microwave ablation transarterial chemoembolization (odds ratio, 1.54; 95% confidence interval, 1.08-2.21; P < .05), and previous ablation (odds ratio, 1.58; 95% confidence interval, 1.09-2.29; P < .05) were found to be statistically significant.

On the basis of the largest microwave ablation database available to date, this study identified novel modifiable and nonmodifiable risk factors of microwave ablation failure. These results can lead to decreasing technical failure rates after microwave ablation.