Calcium electroporation: The bioelectrochemical treatment of spontaneous equine skin tumors results in a local necrosis

Abstract

Electrochemotherapy (ECT) is an anticancer bioelectrochemical therapy where electrical field pulses (electropermeabilization) increase intracellular concentration of antitumor drugs. The procedure is very effective against skin tumors. The restrictive regulations concerning anticancer drugs in veterinary medicine limit use of ECT. Electroporation with calcium (Electroporation Calcium Therapy)(ECaT) was proved to be effective in vivo on induced tumors in laboratory animals. This study evaluated the effects of ECaT in equine sarcoids (spontaneous skin tumors) on an animal cohort. Pulse parameters for ECaT were choosen for using skin contact electrodes. ECaT was applied under general anesthesia. The tumors were removed at different days after the treatment and analyzed by histology. The study assessed the volume fraction of necrosis that was >50% for 9 of 13 sarcoids. Sixteen sarcoids in 10 horses were treated with ECaT. Macroscopic changes (a crust) were observed in 14/16 tumors. The main microscopic changes were necrosis, ulceration,hemorrhages, calcifications and thrombosis. The adverse effect was an inflammatory local reaction. Surrounding tissues were not affected. This targeted effect can be explained by its control by the field distribution in the tissue and on the interstitial diffusion of the injected Ca2+.