Surgical microwave ablation of 397 neuroendocrine liver metastases: a retrospective cohort analysis of 16 years of experience.

Background: Neuroendocrine tumors (NET) constitute a heterogeneous group of malignancies whose incidence has been on the rise over the past two decades, currently documented at 5.25 per 100,000. Liver metastasis develops in over 60% of NET patients. Even after resection recurrence rates are high, underscoring the importance of parenchymal-sparing interventions. In this study, we conducted 105 surgical microwave ablations and examined outcomes related to survival and local recurrence.

Methods: Retrospective review of patients who underwent a surgical microwave ablation (MWA) at a single-center, high-volume institution from September 2007 through December 2022 using a prospective database. Primary outcome was overall survival.

Results: A total of 105 operations were performed on 94 patients, with 397 tumors undergoing MWA. Median tumor size was 1.3 cm (range 0.3-8.0), and the median number of tumors ablated was 2 (range 1-12). Laparoscopic approach was utilized 69.5% of the time. The most common concomitant procedure performed was hepatectomy (33.3%) and cholecystectomy (23.8%). Clavien-Dindo grade III or IV complications occurred in 9 patients (9.6%). Mortality within 30 days occurred in 1 patient (1.1%). The rate of incomplete ablation was 0.3% per tumor. Local recurrence occurred in 2.8% of tumors. Median OS was 9.43 years [95% CI 4.23-14.63 years], with a 5- and 10-year survival probability of 70.2% and 48.2%, respectively.

Conclusion: Surgical MWA offers an efficacious, parenchymal-sparing treatment of hepatic metastasis of NET, with low rates of incomplete ablation and local recurrence per tumor.