High Frequency Electromagnetic Thermotherapy for Cancer Treatment

Background/Aim: Electromagnetic thermotherapy is a new modality for cancer treatment. It applies a highfrequency electrical current to generate a magnetic field and heat up magnetic materials for treating targeted cancers. Using such system, we treat big tumors (more than 1.5 cm in diameter) in a colon cancer bearing murine model. Material and Methods: The high-frequency electromagnetic machine has an input of 220V-55A-60Hz. The output frequency and power are 40 kHz and 20 kW, respectively. The magnetic materials are fine needles made of stainless steel. We used agarose gel and porcine liver for thermo-dosimetry in vitro and ex vivo. During the experiments, IR camera was used to detect the temperature distributions. In an animal model, BALB/C mice were implanted with CT-26 colon cancer cells subcutaneously over their back. After the tumor size grew bigger than 15mm x 15mm, mice were divided into two groups randomly. Group I (n=8) were put in the magnetic field for twenty minutes as a control group. Group II (n=15) were inserted with fine needles into the tumor and magnetic field was used to treat the tumors for twenty minutes. Results: From IR thermography, the needles in a matrix can achieve better temperature distributions in the targeted area than that from a needle alone. In the animal model, the survival rate achieved 90% in the treated group and no residual tumors over their back at the end of observation (60 days); while in the control group, the survival rate on the 45^th day was 0%. Conclusion: Our experiments showed that using high frequency electromagnetic thermotherapy is very effective to treat big tumors in the animal model, and our method has great potential for future clinical applications.