Outcomes after Surgical Microwave Ablation for the Treatment of Colorectal Liver Metastasis.

BACKGROUND: Colorectal cancer (CRC) is the third most common cause of cancer mortality worldwide. Of these, approximately 25% will have liver metastasis. We performed 394 microwave ablations (MWAs) and analyzed outcomes for survival and ablation failure. STUDY DESIGN: We conducted a retrospective review of patients who underwent a surgical MWA at a single-center high-volume institution from October 2006 to September 2022 using a prospectively maintained database. The primary outcome was overall survival. RESULTS: A total of 394 operations were performed on 328 patients with 842 tumors undergoing MWA. Median tumor size was 1.5 cm (range 0.4 to 7.0 cm), with the median number of tumors ablated per operation being 1 (range 1 to 11). A laparoscopic approach was used 77.9% of the time. Concomitant procedures were performed 63% of the time, most commonly hepatectomy (22.3%), cholecystectomy (17.5%), and colectomy (6.6%). Clavien-Dindo grade III or IV complication occurred in 12 patients (3.6%), and all of these patients had undergone concomitant procedures. Mortality within 30 days occurred in 4 patients (1.2%). The rate of incomplete ablation was 1.5% per tumor. Local recurrence occurred at a rate of 6.3% per tumor. Black patients were found to have a higher incidence of incomplete ablation and local recurrence. One-year survival probability was 91% (95% CI 87.9 to 94.3), with a mean overall survival of 57.6 months (95% CI 49.9 to 65.4 months). CONCLUSIONS: Surgical MWA offers a low-morbidity approach to treatment of colorectal liver metastasis, with low rate of failure. This large series reviews the outcomes of MWA as definitive treatment for colorectal liver metastasis.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.