Cancer

Radiofrequency ablation (RF ablation) is a minimally invasive treatment for cancer that is approved by the Food and Drug Administration. It is used to treat liver and kidney cancer and to manage pain resulting from small bone cancers. RF ablation is an alternative to surgery, when surgery is not likely to be successful or has failed or when other medical conditions increase the risk of surgery.

In November of 1996, Dr. Kenneth Tanabe and Dr. Nahum Goldberg performed the first radiofrequency ablation of a patient with a liver tumor in the United States. This history-making procedure was performed in the operating rooms of the Massachusetts GeneralHospital as part of an Institutional Research Board approved clinical research protocol. The experimental procedure was deemed a success in both efficacy and safety. Following this initial trial, researchers in the Division of Surgical Oncology at the Massachusetts GeneralHospital have continued to lead the way in making cutting edge advances in this field.

Recently, the image-guided technique kills cancer cells by heating and destroying them. Radiofrequency is the most commonly used of several methods of destroying tumors by applying heat or cold.

PRINCIPLE

Thermal injury to cells begins at 42℃ with the exposure times to such low-level hyperthermia needed to achieve cell death ranging from 3 to 50 hours depending on the tissue type and conditions. As the temperature increases to above 42℃ there is an exponential decrease in the exposure time necessary for a lethal response. For example, only 8 minutes at 46℃ is needed to kill malignant cells, and 51 ℃ can be lethal after only 2 minutes. At temperatures above 60 ℃ intracellular proteins aredenatured rapidly, cell membranes are destroyed through dissolution and melting of lipid bilayers, and lastly, cell death is inevitable.

During the application of RF energy, a high-frequency alternating current moves from the tip of an electrode into the tissue surrounding that electrode. As the ions within the tissue attempt to follow the change in the direction of the alternating current, their movement results in frictional heating of the tissue. As the temperature within the tissue becomes elevated beyond 60℃ cells begin to die, resulting in a region of necrosis surrounding the electrode.