Calcium Electroporation of Equine Sarcoids

SIMPLE SUMMARY: Sarcoids are skin tumors on horses where better treatment options are needed. Calcium electroporation is a novel anti-cancer treatment where calcium is injected into the tumor, followed by brief electric pulses (electroporation) that transiently open the cell membrane and allow uptake of calcium. This, in turn, induces cell death. In this study, we aimed to investigate the safety and effect of calcium electroporation on sarcoids. Thirty-two sarcoids in eight horses were treated once or twice with calcium electroporation and followed for 12–38 weeks with size-measurement and clinical photographs. The study showed that calcium electroporation is a safe and feasible treatment for sarcoids, including inoperable sarcoids. Six of 27 sarcoids (22%) were completely eliminated, and six further sarcoids (22%) decreased more than 30% in size. No relation between response and location, type, nor size of the sarcoid was observed. Larger studies are needed to further investigate the effect of calcium electroporation on sarcoids. ABSTRACT: Sarcoids are common equine skin tumors where the risk of recurrence after treatment is high, and better treatment options are warranted. Calcium electroporation is a novel anti-cancer treatment where lethally high calcium concentrations are introduced into the cells by electroporation, a method where short high-voltage pulses induce transient permeabilization of the cell membrane. This study investigated the safety and long-term response of calcium electroporation on sarcoids. Thirty-two sarcoids in eight horses were included. The study suggested that calcium electroporation is a safe and feasible treatment for sarcoids, including inoperable sarcoids. Horses were treated once (2/8) or twice (6/8) under general anesthesia, where sarcoids were injected with 220 mM calcium chloride followed by electroporation with 8 pulses of 100 μs, 1 kV/cm, and 1 Hz. Biopsies were taken prior to treatment. The sarcoid size was monitored for 12–38 weeks after the first treatment. Complete response was observed in 22% (6/27) of treated sarcoids, and partial response in 22% (6/27), giving a 44% total response. Treatment efficacy did not appear to be related to location, type, or size. In all non-biopsied lesions, a complete response was seen (4/4). In conclusion, in this small study, 44% of sarcoids responded with 22% of sarcoids disappearing.