Electrical current tumor treatment

Electroporation efficiency depends on the parameters of electric pulses that are delivered to the treated cells using specially designed electrodes and electronic devices. In vitro experiments usually employ parallel plate types of electrodes made of inert metals like stainless steel or platinum but needle types of electrodes are also used for tissue electroporation [24,25,27,28] as well as for tumor treatment apphcations [29-32]. There are two types of electroporator devices available devices with voltage output and those with current output. However, a voltage output device seems to be preferable, which is widely used for diverse applications. 

As early as the late 1700s, Physicians speculated that electrical current could be used to stimulate the heart. In 1882, von Ziemssen used electrical current to directly stimulate the heart of a woman whose anterior chest wall had been removed after resection of a chest tumor. In 1952, ZoU used transthoracic current to pace the heart, and in 1958 the first implantable pacanaker was placed by Ake Senning and Rune Elmquist. At the same time, Furman and Robinson demonstrated the feasibility of transvenous cardiac pacing. In the late 1960s, Mirowski and colleagues pioneered the concept of an implantable device that could be used to defibrillate the heart. Over the last 50 years, implantable cardiac devices have become the primary treatment for bradyarrhythmias and ventricular tachyarrhythmias and have emerged as an important adjunctive therapy for patients with heart failure. It is currently estimated that almost 400,000 pacemakers and defibrillators are implanted annually in the United States. 

The current was applied in the form of electrical pulses in order to permeabilize the membranes of the tumor cells for the entry of the chemotherapeutic agent bleomycin which is a very potent cytotoxic molecule. Clinical complete responses were achieved in 56.4% of the tumors and partial responses were observed in 28.9% of the tumors. This work is thus not strictly electrochemical treatment in the sense of Nordenstrom18 and Xin32 but is rather chemotherapy aided by electrochemical-driven movement of ions, molecules and drugs etc. (e.g., by electroosmosis, electrophoresis) into the tissue regions targeted for necrosis, as in several studies28,51,93 94 described earlier within this chapter. 

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