Conductive Gel Increases the Small Tumor Treatment With Electrochemotherapy Using Needle Electrodes

The combination of chemotherapy drugs and high electric field treatment in local cancer is named electrochemotherapy. The European Standard Operation Procedure of Electrochemotherapy (ESOPE) provides guidelines for treatment of cutaneous and subcutaneous tumors. The electrochemotherapy of numerous tumors varying in sizes is more convenient using needle electrodes. However, ESOPE recommends that needle electrodes are applied to deeper tumors. The application of needle electrodes to treatment of superficial small tumors seems to be practical in electrochemotherapy. Plate electrodes and gel improve the electrochemotherapy efficacy. This technique provides electric field homogeneity in irregularly shaped tissue structures (bulk tumors). We propose an investigation of needle electrode and gel in electrochemotherapy of superficial tumors. In vivo experiment with squamous cell carcinoma (SCC) spontaneous nodules in dog was used to validate the mathematical tissue model. The numerical model considers the tissue conductivity dependent on local electric field. Our studies demonstrated that conductive gel is important for effective treatment of superficial tumors with needle electrodes. The needle electrodes and gel presented reduction of medium current, increased the tumor-free margin, and improved the practical application in relation to plate electrode.