Hyperthermia therapy is treatment that uses heat to change or kill cancer cells. Cells are altered when they encounter higher than normal temperatures, making them more susceptible to radiation therapy and chemotherapy. Extremely high temperatures are used to kill cancer cells directly.
Physicians first began to use heat to destroy tumors in the 19th century. For years, the potential cancer-fighting power of hyperthermia was limited by the difficulty in directing heat to the targeted cells without damaging other cells in the body. However, technological advances have made it easier to focus on cancer cells.
Hyperthermia uses heat between 106 to 113 degrees Fahrenheit (41 to 45 degrees Celsius) to treat cancer by one of three main methods:
Local hyperthermia. Also known as thermal ablation, this involves using great heat – up to 113 degrees Fahrenheit (45 degrees Celsius) – to destroy a small area of cancer cells. A square or round box is placed outside the body over the tumor, and forms of energy – including radio waves, microwaves and ultrasound waves – are used to raise the temperature of the target area. The most commonly used technique is radiofrequency ablation (RFA), which uses high-energy radio waves to create the heat.
Regional hyperthermia. Involves raising the temperature of the body or part of the body to a level that is higher than normal through several methods. The heat disrupts the proteins and structures within the cells. This change may allow cancer treatments, such as radiation therapy, chemotherapy or other anticancer drugs, to work more effectively. Regional therapy is used to treat cancer in organs (such as the liver or lung), limbs or body cavities.
Whole-body hyperthermia. Patient receives the heat from warm-water blankets, inductive coils or thermal chambers (similar to large incubators). Increases the effectiveness of chemotherapy in treating cancers that are spreading (metastatic).
At this time, hyperthermia remains largely an experimental procedure. Only about 30 centers in the United States offer the therapy, according to the American Cancer Society.
However, it is being studied in clinical trials to treat some cancers including:
- Breast
- Endometrial and other Women's reproductive cancers Endometrial
- Kidney
- Liver
- Lung
- Pancreatic
- Prostate
- Soft tissues (sarcomas)
- Thyroid
In many cases, clinical trials combining hyperthermia and other cancer treatments have resulted in a significant shrinkage in tumor size. Hyperthermia appears to be particularly effective when combined with radiation therapy. This combination is adept at damaging two types of cells resistant to radiation therapy alone:
Cells in the process of making DNA for replication
Cells that are acidic and poorly oxygenated. Tumors frequently contain cells that are starved for oxygen, and these cells are particularly susceptible to hyperthermia.
The treatment allows the cancer cells to be heated to higher temperatures than nearby healthy cells. Heat also prevents cells from repairing damage caused by radiation, which helps ensure that the initial destructive effect of radiation treatments have longer-lasting effect.
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