Nanosecond pulsed electric field ablation as first-line curative therapy for hepatocellular carcinoma in high-risk locations a prospective multicenter

Background: Preclinical studies have shown that nanosecond pulsed electric field ablation (nsPEF) is a novel nonthermal ablation modality that can eradicate tumors near critical structures. We conducted the prospective multicenter trial to investigate the efficacy and safety of nsPEF for hepatocellular carcinoma (HCC) in high-risk locations. Materials and Methods: This study was conducted at five hospitals in China. Patients with HCC fulfilling the Milan criteria and located immediately adjacent to (<0.5 cm) the portal vein, hepatic vein, diaphragm, gastrointestinal tract, liver capsule, or gallbladder were enrolled. The primary endpoint was the complete ablation rate at 1 month, and adverse events. The secondary endpoints included local tumor progression (LTP), recurrence-free survival (RFS), and overall survival (OS). Results: From March, 2020, to June, 2022, 192 patients were enrolled (148 males [77.1%]; median age 58.5 years [interquartile range, 51.0-66.0 years]. The median follow-up duration was 33.5 months. The technical success rate was 99.5%. Complete ablation was achieved in 91.7% of the 217 tumors. Complete ablation rates at 1 month were significantly higher in tumors < 2 cm vs. ≥ 2 cm (90.1% vs. 71.7%, p = 0.002). The estimated 1-, 2- and 3-year cumulative incidences of LTP were 9.8%, 13.8%, and 15.7%, respectively. The maximum tumor diameter [hazard ratio (HR) = 2.62, p = 0.014] and age (HR = 0.42, p = 0.026) were independent predictive factors for LTP. The RFS rates at 1-, 2- and 3-year were 72.2%, 51.7%, and 43.5%, respectively. No periprocedural thermal damage was observed. Grade ≥ 3 treatment-related adverse events occurred in nine (5.6%) patients. Conclusion: To our knowledge, this was the first prospective trial demonstrating that nsPEF was effective and relatively safe for HCC in high-risk locations, and may serve as an alternative therapeutic option for HCC suboptimal for thermal ablation.