Irreversible electroporation of hepatocellular carcinoma and colorectal cancer liver metastases: A nationwide multicenter study with short- and long-term follow-up

Introduction: A nationwide multicenter study was performed to examine short- and long-term effects of irreversible electroporation (IRE) for hepatocellular carcinoma (HCC) and colorectal cancer liver metastases (CRCLM). IRE is an alternative method when thermal ablation is contraindicated because of risk for serious thermal complications. Methods: All consecutive patients in Sweden treated with IRE because of HCC or CRCLM, were included between 2011 and 2018. We evaluated medical records and radiological imaging to obtain information regarding patient-, tumor-, and treatment characteristics. We also assessed local tumor progression, and survival. Results: In total 206 tumors in 149 patients were treated with IRE. Eighty-seven patients (58.4%) had colorectal cancer liver metastases, and 62 patients (41.6%) had hepatocellular carcinoma. Median tumor size was 20 mm (i.q.r. 14–26 mm). Median overall survival for CRCLM and HCC, were 27.0 months (95% CI 22.2–31.8 months), and 35.0 months (95% CI 13.8–56.2 months), respectively. Median follow-up time was 58 months (95% CI 50.6–65.4). Local ablation success at six and twelve months for HCC was 58.3% and 40.3%, and for CRCLM 37.7% and 25.4%. The median time to local tumor progression (LTP) for HCC was 21.0 months (95% CI: 9.5–32.5 months), and for CRCLM 6.0 months (95% CI: 4.5–7.5 months). At 30-day follow-up, 15.4% (n = 23) of patients suffered from a complication rated as Clavien-Dindo grade 1-3a. Three patients (2.0%) had grade 3b-5 with one death in a thromboembolic event. Conclusion: IRE is a safe ablation modality for patients with liver tumors that are located in such a way that other treatment options are unsuitable.