Electroporation treatments have not historically utilized real-time temperature feedback to monitor local tissue temperatures. Thermal heating, which occurs during electroporation protocols, can result in unintended and deleterious thermal damage. Tissue heating is difficult to predict due to variations in tissue properties throughout patient populations, non-uniform biological thermal dissipation, and joule heating that occurs during electroporation procedures.
Our study demonstrates the successful treatment (>93% complete response rate) of naturally occurring spontaneous tumors in an equine population with algorithmically controlled electroporation (ACE). ACE utilizes a temperature control algorithm to mitigate thermal heating of tissue during treatment delivery. A custom-built applicator with a fiberoptic temperature sensor and treatment planning simulations for thermal increase and treatment zone sizes were developed prior to treating equine patients at North Carolina State University School of Veterinary Medicine.
Equine patients were treated while awake and standing under mild sedation, with individual tumors (n=25) receiving a total active treatment time or integrated energized time (IET) of either 0.005, 0.01, or 0.02 seconds of electrical energy at 2000V protocols. IET treatment durations were selected based on tumor size, which ranged from 5mm to 32mm in diameter. Variations in bulk tissue resistance resulted in a current range of 3-41A during treatments. The ACE algorithm, by regulating average power delivery during treatment, maintained temperatures below cumulative thermal damage thresholds with an average peak temperature of 42.2°C+/-5.2°C observed. A complete response was found in 93% (14 out of 15) of tumors treated with 0.01 seconds IET and 100% (3 out of 3 and 4 out of 4) when the IET was .005 or 0.02 seconds, respectfully. ACE treatment strategy successfully maintained tissue temperatures below deleterious thermal damage thresholds while minimizing treatment times.