Ablation of Perivascular Hepatic Malignant Tumors with Irreversible Electroporation

BACKGROUND: Ablation is increasingly used to treat primary and secondary liver cancer. Ablation near portal pedicles and hepatic veins is challenging. Irreversible electroporation (IRE) is a new ablation technique that does not rely on heat and, in animals, appears to be safe and effective when applied near hepatic veins and portal pedicles. This study evaluated the safety and short-term outcomes of IRE to ablate perivascular malignant liver tumors. STUDY DESIGN: A retrospective review of patients treated with IRE between January 1, 2011 and November 2, 2011 was performed. Patients were selected for IRE when resection or thermal ablation was not indicated due to tumor location. Treatment outcomes were classified by local, regional, and systemic recurrence and complications. Local failure was defined as abnormal enhancement at the periphery of an ablation defect on post-procedure contrast imaging. RESULTS: Twenty-eight patients had 65 tumors treated. Twenty-two patients (79%) were treated via an open approach and 6 (21%) were treated percutaneously. Median tumor size was 1 cm (range 0.5 to 5 cm). Twenty-five tumors were <1 cm from a major hepatic vein; 16 were <1 cm from a major portal pedicle. Complications included 1 intraoperative arrhythmia and 1 postoperative portal vein thrombosis. Overall morbidity was 3%. There were no treatment-associated mortalities. At median follow-up of 6 months, there was 1 tumor with persistent disease (1.9%) and 3 tumors recurred locally (5.7%). CONCLUSIONS: This early analysis of IRE treatment of perivascular malignant hepatic tumors demonstrates safety for treating liver malignancies. Larger studies and longer follow-up are necessary to determine long-term efficacy.