Treatment of Infiltrative Superficial Tumors in Awake Standing Horses Using Novel High-Frequency Pulsed Electrical Fields

Christopher R. Byron,Eduardo L. Latouche,Matthew R. DeWitt,John L. Robertson,Rafael V. Davalos

doi:10.3389/fvets.2019.00265

Abstract

Irreversible electroporation is a proven ablation modality for local ablation of soft tissue tumors in animals and humans. However, the strong muscle contractions associated with the electrical impulses (duration, 50–100 μs) requires the use of general anesthesia and, in most situations, application of neuromuscular blockade. As such, this technology is not used in an outpatient setting for ablating common cutaneous tumors (e.g., squamous cell carcinoma or melanoma) in humans or animals. Recently, high-frequency irreversible electroporation (H-FIRE) technology has been developed to enable electroporation of tumors without stimulation of nearby skeletal muscle. H-FIRE administers bursts of electrical pulses (duration, 0.5–2 μs) through bipolar electrodes placed in tumor parenchyma. We hypothesized that H-FIRE could be used to safely ablate superficial tumors in standing, awake horses without the need for general anesthesia. Here, we describe the treatment of superficial tumors in five horses using this novel ablation therapy without the need for general anesthesia. In each case, H-FIRE therapy predictably ablated tumor volume. All patients tolerated the procedure, no complications developed, and veterinary personnel safety was maintained. The H-FIRE treatment may be useful for treatment in veterinary and human patients in an outpatient setting without the need for hospitalization, general anesthesia, and advanced monitoring techniques.

Highlights

Cutaneous tumors, including sarcoid, squamous cell carcinoma, and melanoma, are extremely common in horses [1, 2]
ECG artifacts (H-FIRE-associated spike) were visible during delivery of high-frequency irreversible electroporation (H-FIRE) electrical impulses; no cardiac electrical abnormalities were induced by the treatment
The results of this study show that H-FIRE-mediated tumor ablation can be performed safely in standing horses with minimal risk of injury to patients or veterinary personnel

Summary

Introduction

Cutaneous tumors, including sarcoid, squamous cell carcinoma, and melanoma, are extremely common in horses [1, 2]. While many small, circumscribed lesions can be controlled with surgical resection, cryoablation, hyperthermy, or localized chemotherapy (e.g., topical 5-fluorouracil or cisplatin in oil or bioabsorbable beads), infiltrative lesions are typically difficult to control. Complete resolution may not be obtained because local infiltration around critical structures (nerves, major blood vessels) precludes surgical removal, or because of extensive local tissue invasion by tumors and/or the presence of recurrent, locally-aggressive growth of tumors and multiple tumor sites. The use of multiple treatment modalities, such as a combination of surgical resection and local. Tumor Electroporation in Awake Horses chemotherapy, is common in attempting therapy of such tumors. Many treatments must be performed during multiple general anesthetic procedures. All of these limitations indicate a pressing need for development of novel methods for management of such tumors

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