Hyperthermia

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Hyperthermia - heat treatment for cancer

Hyperthermia (also called thermal therapy or thermotherapy) is a type of cancer treatment in which body tissue is exposed to high temperatures (up to 113°F).

Research has shown that high temperatures can damage and kill cancer cells, usually with minimal injury to normal tissues (1). By killing cancer cells and damaging proteins and structures within cells (2), hyperthermia may shrink tumors.

Several methods of hyperthermia are currently under study, including local, regional, and whole-body hyperthermia.

In local hyperthermia, heat is applied to a small area, such as a tumor, using various techniques that deliver energy to heat the tumor. Different types of energy may be used to apply heat, including microwave, radiofrequency, and ultrasound. Depending on the tumor location, there are several approaches to local hyperthermia:

External approaches are used to treat tumors that are in or just below the skin. External applicators are positioned around or near the appropriate region, and energy is focused on the tumor to raise its temperature.

Intraluminal or endocavitary methods may be used to treat tumors within or near body cavities, such as the esophagus or rectum. Probes are placed inside the cavity and inserted into the tumor to deliver energy and heat the area directly.

Interstitial techniques are used to treat tumors deep within the body, such as brain tumors. This technique allows the tumor to be heated to higher temperatures than external techniques. Under anesthesia, probes or needles are inserted into the tumor. Imaging techniques, such as ultrasound, may be used to make sure the probe is properly positioned within the tumor. The heat source is then inserted into the probe. Radiofrequency ablation (RFA) is a type of interstitial hyperthermia that uses radio waves to heat and kill cancer cells.

In regional hyperthermia, various approaches may be used to heat large areas of tissue, such as a body cavity, organ, or limb.

	Deep tissue approaches may be used to treat cancers within the body, such as cervical or bladder cancer. External applicators are positioned around the body cavity or organ to be treated, and microwave or radiofrequency energy is focused on the area to raise its temperature.
	Regional perfusion techniques can be used to treat cancers in the arms and legs, such as melanoma, or cancer in some organs, such as the liver or lung. In this procedure, some of the patient’s blood is removed, heated, and then pumped (perfused) back into the limb or organ. Anticancer drugs are commonly given during this treatment.
	Continuous hyperthermic peritoneal perfusion (CHPP) is a technique used to treat cancers within the peritoneal cavity (the space within the abdomen that contains the intestines, stomach, and liver), including primary peritoneal mesothelioma and stomach cancer. During surgery, heated anticancer drugs flow from a warming device through the peritoneal cavity. The peritoneal cavity temperature reaches 106–108°F.

Whole-body hyperthermia is used to treat metastatic cancer that has spread throughout the body. This can be accomplished by several techniques that raise the body temperature to 107–108°F, including the use of thermal chambers (similar to large incubators) or hot water blankets.

The effectiveness of hyperthermia treatment is related to the temperature achieved during the treatment, as well as the length of treatment and cell and tissue characteristics. To ensure that the desired temperature is reached, but not exceeded, the temperature of the tumor and surrounding tissue is monitored throughout hyperthermia treatment. Using local anesthesia, the doctor inserts small needles or tubes with tiny thermometers into the treatment area to monitor the temperature. Imaging techniques, such as CT (computed tomography), may be used to make sure the probes are properly positioned.

Cancer cures and advice Index

hyperthermia

Hyperthermia is almost always used with other forms of therapy (radiation therapy, chemotherapy, and biological therapy) to increase their effectiveness. The area may be heated externally with high-frequency waves aimed at a tumor from a device outside the body. To achieve internal heating, one of several types of sterile probes may be used, including thin, heated wires or hollow tubes filled with warm water; implanted microwave antennae; and radiofrequency electrodes.

Hyperthermia does not usually cause marked increase in radiation side effects. Heat applied directly to the skin, however, can cause discomfort or even significant local pain in about half the people treated with this procedure. It can also cause blisters, which generally heal rapidly.

Cancer cells typically die between 107 F and 111 F, depending on exposure time and other factors. Cancer cells do not like oxygen, do not like high pH (alkaline) conditions, but love sugar and low pH (acid conditions). Very thin thermocouples are taped to the surface of the skin over the affected area, and are used to monitor the temperature over time which is induced by the microwave machine. The affected area is typically heated to between 114 F and 120 F. This degree of heating is normally not uncomfortable, and if there is any discomfort, the heating is adjusted downwards.

Experience has shown that the positive effects of heating the affected area (including increased oxygen supply) lasts for about 24 hours. Therefore, the best results have been obtained when the treatments continue 5 days per week

Low dose radiation is provided to the affected area either before or after the heat treatment and also continues 5 days per week. Radiation dosages typically start about 180 centiGrays (cGy) per day, and then after a few weeks, the radiation dosages are gradually reduced as the treatment progresses, and after 10 or 12 weeks, the radiation dosages are down to about 30 or 50 cGy per day. The total radiation dose after 10 or 12 weeks adds up to about 5000 or 7000 cGy, but given over a long period of time. Conventional medicine generally provides much higher levels of radiation given over a much shorter period of time, which has been found to be much less effective for successful treatment of cancer.

These low dose radiation treatments serve several purposes:

	to kill the cancer cells that survive hyperthermia heat treatments because they get the benefit of cooling from adjacent healthy tissue.
	to kill cancer cells that try to migrate to adjacent areas, such as adjacent lymph glands.
	to kill cancer cells in areas that might have been missed by the hyperthermia heat treatments.

After several weeks, the tumor is seen to shrink in size and eventually to disappear completely. Patients are encouraged to drink lots of water to assist in flushing away through the kidneys any toxins released as the cancer cells die.

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