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| Fig. 1: A patient preparing to receive Radiation Therapy for treatment of a tumor. (Source: Wikimedia Commons) |
Radiation fields today serve as a method of fighting cancer. The high energy, ionizing radiation can disrupt the structure of the DNA in tumor cells; however, the same affects can affect normal tissue in the body. Despite precision of the increasingly accurate devices being developed, some non-cancerous cells will still be effected in the process of treatment. Furthermore, the treatment process involves large machinery that is not mobile while treatments are needed almost daily, so a patient must travel to see a physician quite frequently. Fig. 1 shows a patient preparing for radiation therapy. Chemotherapy, another method of treatment that affects the entire body, has been associated with severely uncomfortable side effects like nausea and vomiting during treatment and later recurring fatigue long term. [1]
Radiation therapy side effects can happen immediately after exposure, but further effects may not manifest for weeks or even months. Furthermore, the effect of the radiation therapy may differ depending on the system treated. Acute or early effects are seen during or within a few weeks of treatment. Damage from the radiation can result in a decrease in cell number due to stem-cell damage, so tissue will not properly turnover. Cell death of even normally functioning tissue can be caused by the same ionizing radiation that damage tumor cells DNA repair mechanisms. Long term effects include but are not limited to, wound healing slowing due to endothelial cell adhesion failures, overall tissue mass decrease, and even carcinogenesis. [2]
Electric fields have been a topic of exploration as a potential therapy method that would selectively target abnormal cancer cells. By using 100 KHz to 1 MHz AC fields, called Tumor Treatment Fields (TTF), researchers and clinicians have been able to disrupt the spindle fibers associated with cell division and cytokinesis. Using this model, TTF therapy has been utilized in humans for Gliboblastoma, as the glial cells do not rapidly divide naturally. The device non-invasively applies an electric field through electrodes attached to the skin. In patients with a recurring Glioblastoma treated with TTF devices, the average life span is 62.2 weeks, which is more than double the median of control patients. The treatment has shown to vastly reduce the size of the tumor. The therapy even resulted in a patient being completely tumor free after ten months. Moreover, in the ten patients treated with TTF therapy, there were no treatment related adverse effects, and no significant changes in blood chemistry other than the increased liver enzyme associated with anti-epileptic drugs. The TTF device by Novocure also allowed for patients to move about freely and receive treatment through a mobile wearable apparatus [3]
Ultimately, the usage of Tumor Treating Fields in a greatly beneficial technology in that it allows the patient to live freely without the same negative side effects associated with chemotherapy or radiation while still being able to effectively fight off slowly growing tumor cells. There are clinical studies looking into utilizing not only the TTF therapy but also common chemotherapeutic agents like Temozolomide in combination to further combat aggressive tumors. [4] This therapy is an incredible way of combatting aggressively dividing tumor cells in systems that do not naturally divide quickly. Hopefully, utilizing this method of electrically disrupting mitotic spindles, researchers can find an equivalent therapy for more rapidly dividing cell systems like skin cancer as to non-invasively treat malignant growths without having significant serious side effects.
© Mitchell So. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] K. Lotfi-Jam et al., "Nonpharmacologic Strategies for Managing Common Chemotherapy Adverse Effects: A Systematic Review," J. Clin. Oncol. 26, 5618 (2008).
[2] H. B. Stone et al., "Effects of Radiation on Normal Tissue: Consequences and Mechanisms," Lancet Oncol. 4, 429 (2003).
[3] E. D. Kirson et al., "Alternating Electric Fields Arrest Cell Proliferation in Animal Tumor Models and Human Brain Tumors," P. Natl. Acad. Sci. USA 104, 10152 (2007).
[4] A. Welch, "Electromagnetic Therapy Shows Promise for Patients with Brain Cancer," CBS News, 15 Dec 15.
