Electroporation therapy
Electroporation therapy is an innovative treatment method used primarily for certain types of cancer, including squamous cell carcinoma, basal cell carcinoma, melanoma, and others. It works by applying short bursts of intense electrical pulses to tumor cells, temporarily increasing the permeability of their cell membranes. This increased permeability allows for enhanced uptake of chemotherapeutic agents, leading to a higher concentration of drugs within the cancer cells and improving their effectiveness. The procedure typically utilizes devices known as electroporators, which consist of multiple electrode needles that create an electric field directly within the tumor.
There are two main techniques within electroporation: reversible and irreversible. Reversible electroporation leads to transient pores in the cell membrane, allowing drug entry, while irreversible electroporation can cause permanent pore formation, resulting in cell death. Studies have shown that combining electroporation with the cytotoxic drug bleomycin significantly improves treatment outcomes compared to either method alone, offering effective cancer cell killing with minimal side effects. Patients may experience mild electric shocks during the procedure, but the therapy is generally well-tolerated, potentially reducing the adverse effects typically associated with chemotherapy. Electroporation therapy represents a promising avenue in cancer treatment, emphasizing the importance of ongoing research and clinical trials.
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Electroporation therapy
Also known as: EPT
Definition:Electroporation therapy is a process that uses high-intensity electrical currents that increase the permeability of cell membranes and enhance the ability of cytotoxic drugs, vaccines, and genes to enter into tumor cells.
Cancers treated:Squamous cell carcinoma, basal cell carcinoma, melanoma, head and neck cancers, cutaneous and subcutaneous tumors, Kaposi sarcoma, breast cancer, liver cancer, pancreatic cancer
Delivery routes: Electrical pulses are delivered directly into tumors using special devices called "electroporators" or "applicators."
Description: Many potentially effective anticancer drugs are limited by their ability to permeate the cell membranes and gain entry into tumor cells. The lipid bilayers of cell membranes possess unique physical and biochemical properties that prevent easy entry of exogenous materials. The principle of electroporation therapy is to increase permeability of the cell membranes by pulses of intense electric current, leading to formation of transient pores in the cell membrane. Pores aid in easy uptake of cytotoxic drugs and increase the intracellular drug concentration, thereby increasing their chances of direct action on tumor cells.
An electroporator consists of a circular array of several electrode needles (ranging from six to sixteen, depending on arrangement) that deliver pulses directly inside tumors and create an electric field through potential differences generated between these electrodes. Effective electroporation depends on strength and duration of the applied electric field. Optimization is required for each type of tissue and the kind of molecule being delivered (for example, drug vs. deoxyribonucleic acid, or DNA). Application of short pulses of electric field results in the transient formation of pores on the cell membrane. Pores close shortly after the application of electric field is terminated, resulting in almost an entrapment of drugs or other molecules. Application of longer and/or stronger pulses, a technique called "irreversible electroporation," can induce permanent pore formation in the cell membrane and thereby initiate cell death.
Electroporation therapy results in enhanced killing of cancer cells and early necrosis of tumors. Clinical trials on squamous cell carcinoma patients that incorporated a treatment regimen with the drug bleomycin (a cytotoxic drug derived from the bacterium Streptomyces verticillus), followed by electroporation, demonstrated complete remission in a significant proportion of patients and partial remission in others. Combination therapy with bleomycin and electroporation was more effective than either treatment alone. Bleomycin in combination with electroporation dramatically enhanced the percentage of cells killed. Among the multitudes of drugs tested in combination with electroporation, bleomycin has been proven to be the most effective. Combined therapy also increases the duration of drug retention and decreases the dose of drug needed for effective treatment.
Side effects: Minimal side effects have been observed with electroporation therapy. Some electric shocks can be experienced after administration of electric pulses. When used to deliver chemotherapy drugs, electroporation may reduce side effects from the medication.
Bibliography
Martin, Robert G. C., et al. "Irreversible Electroporation of Unresectable Soft Tissue Tumors with Vascular Invasion: Effective Palliation." BMC Cancer 14.540 (2014): n. pag. Web. 2 Oct. 2014.
Mir, Lluis M. "Application of Electroporation Gene Therapy: Past, Current, and Future." Methods in Molecular Biology 423 (2008): 3–17. PDF file.
Peck, Morgan E. "Electroporation 'Knife' for Cancer: A New Electrical Approach to Cutting Out Cancerous Tumors." IEEE Spectrum. IEEE Spectrum, 4 Feb. 2009. Web. 2 Oct. 2014.
Silk, M., et al. "Safety of Irreversible Electroporation (IRE) Treatment for Metastatic Disease in Humans." Journal of Vascular and Interventional Radiology 24.4 (2013): S21–S22. Web. 2 Oct. 2014.
Sundararajan, Raji, ed. Electroporation-Based Therapies for Cancer: From Basics to Clinical Applications. Cambridge: Woodhead, 2014. Digital file.