Introduction

High frequency irreversible electroporation (H-FIRE) is a non-thermal ablative technique that utilizes short, intense, bipolar electrical pulses to create permanent nanopores in cellular membranes resulting in cell death. We hypothesize that treatment of canine hepatocellular carcinoma (HCC) with H-FIRE results in preferential neoplastic cell death. Our objective is to characterize the response and lethal threshold of HCC and non-neoplastic liver to H-FIRE, and the tumor microenvironment response to the treatment.

Methods

Dogs with HCC were recruited and staged with triple-phase CT. Using finite 3D element analysis, 3D modeling for treatment planning was performed and H-FIRE was delivered with an open approach through 2-5-2 us bursts to the tumor and non-neoplastic liver. Tumor was excised and patients were recovered in ICU. Abdominal CT was performed at 24 hours, 4 days, and 1 month post treatment to monitor the non-neoplastic liver ablation. Histopathology and IHC for Iba-1, CD3, CD79a, and FOXP3 was performed to characterize tumor ablation and potential immune cell infiltrates. Tumor microenvironment changes were evaluated using the NanoString canine immuno-oncology panel.

Results

Three dogs have been treated with no dogs experiencing complications associated with H-FIRE. Histopathology of treated HCC demonstrated ablation characterized by focal hemorrhage and hepatocyte degeneration. Follow-up CT on the non-neoplastic liver treated with H-FIRE suggests that ablation volumes for non-neoplastic liver are smaller than those of HCC, under the identical pulse parameters. H-FIRE results in intra-tumoral increase in immune cell infiltrate and activation of phagocytic, cytotoxic T-cell, and NK-cell activity.

Conclusion

Our findings suggest H-FIRE preferentially targets neoplastic cells.

Funding Information

Veterinary Cancer Society Theilen Resident Research Grant Grayton Frielander Memorial Fund.