The electrochemical treatment (EChT) of tumors implies that tumor tissue is treated with a continuous direct current through two or more electrodes placed inside the tumor or in its close vicinity. The design of the electrodes are similar to acupuncture needles.
When two or more electrodes are inserted into the tissue a series of electrochemical reactions are taking place. When a practically insoluble electrode material such as platinum is used, the main electrode reactions are decomposition of water along with oxidation and reduction of substances dissolved in the tissue.
Figure 1. A schematic on the principle for electrochemical treatment of tumors
One of the pioneers in Sweden was the professor in radiology Bjorn Nordenstrom who in the mid eighties published a series of reports on EChT of human tumors (Nordenstrom, 1983; 1989). He treated lung metastases (carcinomas) and a few primary lung tumors. Many of the patients were, for various reasons, unsuitable for surgical, radiotherapeutic, or chemotherapeutic treatment. The average delivered coulomb (C) dosage was 80 C/cm of tumor diameter. Regression was obtained in 12 out of 26 tumors and no signs of progression were detected after a 2.5-year follow-up period in these cases. There was no reported lethal outcome of the therapy.
Up to the present day, more than 15 000 treatments of human tumors have been preformed in China. A summary of the results can be found in a review from 2000, by Nilsson and co-workers
The destructive mechanisms
Electric field and Chlorine
Many suggestions have been made on which should be the main cause of tissue destruction after electrochemical treatment. Some authors claim that the electric field has an important impact on cell death or tumor tissue remodelling. The electric field causes a flux of interstitial water, electro-osmosis, from the anode towards the cathode, since the water molecules act like a dipole. Consequently, the tissue surrounding the anode dehydrates while oedema is obtained around the cathode. Charged substances, dissolved or suspended in tissue, migrate in the electric field and accumulation of ions and charged tissue constituents are obtained at certain and different locations in the electric field. The electric field influences the ion exchange across the cell membranes. Hence, the transmembrane potential is altered and thereby the conditions e.g. for many essential enzyme-regulated reactions.
The impact of pH
With little doubt though, most reports have elucidated the extreme pH-gradient that occurs at EChT. At the anode, as low pH as 1 has been measured. While at the cathode the prominent alkalisation yields pH levels as high as 13. At these extreme pH values, the tissue proteins become denaturated and the cell structure collapses and the cell eventually dies.
The acidic microenvironment of tumor tends to release more hydrogen during the electrical treatment, which is shown recently and will be introduced in our next blog.
Figure 2. The equipment used for EChT. In the background the potentiostat is seen. In the foreground a Palm pilot IIIXe is attached to a portable keyboard.
Clinical trials of breast cancer
The results of clinical reports are very impressive.
Xin et al. modified their electrode placement technique and both anodes and cathodes were now placed inside the tumors, with anodes in the center and cathodes in the periphery. This modification did not only protect the normal tissue from destruction, but was also shown to enhance the therapeutic effect. It was stated that the tumor tissue-killing diameter around each electrode was about 3 cm, and thus, the distance between electrodes should not exceed 3 cm. Typical treatment parameters were 6-8 V,40-80 mA and a coulomb dosage of 100 C/cm of tumor diameter.
One of impressive results are from breast cancer. In one report of 132 cases of intermediate and advanced breast cancer, 125 cases had complete remission and 6 cases had partial remission. In another report 42 cases of advanced breast cancer, 21 cases had recurrence after surgery, 11 cases had lymph node metastasis, and 10 cases had breast ulcer. 31 of the cases were not operatable. After the EChT, 21 cases had complete remission and 14 cases had partial remission. The five-year survival in these reports are also impressive.
We modified the electrochemical treatment to produce local hydrogen, with minimal invasion, good tolerance and high safety. The pilot data are very encouraging.
Nilsson E, von Euler H, Berendson J, Thörne A, Wersäll P, Näslund I, Lagerstedt AS, Narfström K, Olsson JM. Electrochemical treatment of tumors. Bioelectrochemistry. 2000;51(1):1-11. doi: 10.1016/s0302-4598(99)00073-2.