Novel application for electrochemotherapy: Immersion of nasal cavity in dog.

Electrochemotherapy is a new modality of local cancer treatment that increases the delivery of chemotherapy drugs into tumor cells by applying intense electric fields. This novel electrochemotherapy application was applied as an adjuvant to surgery and eliminated intranasal tumors in dog. The treatment challenges are the surgery limitations due to anatomy and residual tumor in the bone cavity. Most of the tumoral mass on nasal cavity was surgically removed. The internal nasal cavity was immersed in liquid and bleomycin before applying electric field. The solution was necessary to increase the superficial contact between plate electrodes and residual tumor. The numerical study demonstrated electrochemotherapy efficiency in different clinical situations. The proximity between electrodes and bone (<3 mm) and bone irregularities affect the electric field distribution on tumoral tissue. The tumoral tissue around bone protuberances tends to be eliminated. Electrochemotherapy with plate electrodes inside the cavity might not be effective. Different values of electric conductivity solution were studied; the ideal value was 0.5 S/m. The numerical and experimental results confirm the successful application of electrochemotherapy on dog nasal cavity.

Numerical model of dog mast cell tumor treated by electrochemotherapy.

Electrochemotherapy is a combination of high electric field and anticancer drugs. The treatment basis is electroporation or electropermeabilization of the cell membrane. Electroporation is a threshold phenomenon and, for efficient treatment, an adequate local distribution of electric field within the treated tissue is important. When this local electric field is not enough, there is a regrown tumor cell; however, if it is stronger than necessary, permanent damage to the tissue occurs. In the treatment of dogs, electrochemotherapy is not yet an established treatment for mast cell tumor in veterinary medicine, although there are studies showing evidence of its effectiveness. In this study, we examined electrochemotherapy of dog mast cell tumor with numerical simulation of local electric field distribution. The experimental result was used to validate the numerical models. The effect of tumor position and tissue thickness (tumor in different parts of dog body) was investigated using plate electrodes. Our results demonstrated that the electrochemotherapy is efficient and flexible, and even when the tumor extends into the subcutis, the treatment with plate electrode eliminated the tumor cells. This result suggests that electrochemotherapy is a suitable method to treat mast cell tumors in dog.