Electrochemical Treatment Of Tumors: Primary Mechanisms Of Tumor Destruction And Technique Of Electrode Placement

Electrochemical treatment of tumors (EChT) is a local therapy of tumor, in which several pairs of electrodes employed as anodes and cathodes are placed inside the tumor, and then direct current is forced to flow through the tumor between these electrodes. By prescheduled period of time, various degree of tumor destruction can be achieved by electrolysis treatment. More than 10000 patients had been treated with EChT in China since 1989. The total curative effect is more than 80%. However, the mechanism of tumor destruction, the electrode placement technique and how to prescribe the dosage are not completely clear by now, and, as a result, the development of EChT as a clinical therapy is hindered.In this thesis, we tried to work out the primary destructive mechanism of EChT and the technique of electrode placement. The main contents and conclusions are as follows:1. The primary destructive mechanism of EChTIn chapter 2, the primary destructive mechanism of EChT was investigated systematically. The destructive action of electrolysis products, such as pH values and chlorine gas on cancer cells was investigated in the cancer cells suspension. And the experiments were performed with the cancer cell suspended agar, human cancer tissue and hepatoma tumors in rats in order to find out the destructive mechanism caused by anodic and cathodic process during electrolysis.The experimental results indicated that the extreme pH value, including both acidic and basic environment, caused by electrolysis, could lead to the destruction of the cancer cells and tumor tissues. The condensed chromatin is found to be the main morphological characteristic of cell changes in an acidic medium, while gross cytolysis is a distinctive feature of cell destruction in an extreme basic medium. The destructive action of cathodic process is more serious than that of anodic process.Nevertheless, in our experiments we do not found obvious destructive effect of chlorine on the cancer cells.2. The technique of electrode placementIn chapter 3, the pH indicator was introduced into agar to investigate the formation of the area of extreme basic and acidic around the electrodes during electrolysis. It can be found that the shape and the distribution of the area of extreme pH value are influenced evidently by the placement of electrode. If the anode and the cathode are placed inside the cancer cell suspended agar (or cancer tissues) together, after treatment with electrolysis, a neutral area in which tumor (or agar) pH remains unchanged always retains, and results in the imperfect destruction of tumor cells and tumor tissues.While the volume of extreme basic or acidic caused by electrolysis is proportionalto the total charge involved in the electrolysis, treatments with low current and longer treatment times results in larger volume compared to treatments with higher current and shorter treatment tune.In order to achieve the well-distributed extreme basic area in tumor tissues, the multi-cathodes should be placed inside the tumor tissue together, at meanwhile the same value of current should be controlled to flow through each cathode. Both human cancer tissues and hepatoma in rats were treated with electrolysis under this rule hi vitro and in vivo respectively. It is found that the well-distributed destruction and the obvious inhibition of tumor growth are achieved.3. The relationship between the conductivity change and destruction of the tissueIn chapter 4, the relationship between the conductivity changes and the destruction of the tissues during electrochemical treatment was studied with the aim of finding some parameter that can be used to characterize the degree of deterioration of the tissues during treatment. The pork liver and the human cancer tissue were treated with constant direct current. The changes of the conductivity were measured during electrochemical treatment. The morphological changes of the cells after treatment were investigated under optical microscope. Parallel changes were observed between the conductivity an...