Since ancient times, it is believed that elevated body temperatures are beneficial as an immune response against any disease-causing agents, even in the cancer treatment. However, the realization that heat can be an effective approach for cancer treatment can be dated over the past few decades.
Fever is defined as ‘a state of elevated core temperature, which is often, but not necessarily, part of the defensive responses of multicellular organisms (host) to the invasion of live (microorganisms) or inanimate matter recognized as ‘pathogenic or alien by the host.’ according to the International Union of Physiological Sciences,’ Glossary of terms for thermal physiology. Unlike fever, hyperthermia involves an unregulated rise in body temperature. Researches have shown that high temperatures can damage and kill cancer cells, usually with minimal injury to healthy tissues.
What is Hyperthermia?
Hyperthermia, also called thermal therapy or thermotherapy) is the carefully controlled use of heat (high temperatures up to 45°C) for medical purposes, especially for cancer treatment. Research has shown that by killing cancer cells, usually with minimal injury to healthy tissues, hyperthermia may shrink tumors, even reverse cancer.
The new interest in the use of hyperthermia in cancer therapy is related to two findings. The first is the radiobiological evidence indicating that there may be a significant advantage in the use of heat alone or combined with other therapies to enhance the inactivation of tumor cells. The second is that early clinical investigation with stubborn malignant tumors at temperatures have shown tumor regression response rate over 70% between 41 degrees C and 45 degrees C, even without showing no sign of typical tissue complication.
How Is Hyperthermia Used in Cancer Treatment?
Hyperthermia harms cancer cells that radiation cannot damage. Numerous clinical trials have studied hyperthermia that has focused on the treatment of many types of cancer. When hyperthermia is combined with other treatments, it has shown that there may be a significant reduction in tumor size.
What Are the Different Methods of Hyperthermia?
Treatment can be local, regional, or whole-body hyperthermia, depending on the extent of the area treated. In local hyperthermia, doctors apply heat to a small area as a tumor. In regional hyperthermia, doctors apply heat to large areas of tissue, such as a body cavity, organ, or limb. In whole-body hyperthermia, heat is applied by several techniques to the whole body to treat metastatic cancer.
The temperature reached during the treatment, the length of treatment, and cell and tissue characteristics, all may affect the result of hyperthermia treatment. The temperature of the tumor and surrounding tissue should be monitored throughout hyperthermia treatment to make sure that the necessary temperature is reached but not exceeded.
Hyperthermia as an Immunotherapy Strategy for Cancer
Does Hyperthermia Have Any Side Effects?
If the temperature remains between 41 degrees C and 45 degrees C during hyperthermia treatment, most normal tissues are not damaged. However, higher temperatures may occur in various spots because of regional differences in tissue characteristics. This may result in burns, blisters, discomfort, or pain. Most of these side effects are temporary. Moreover, current instruments can deliver heat precisely. Nevertheless, hyperthermia must be carefully controlled and should be done by experienced doctors.
The use of hyperthermia as supportive therapy to existing immune therapy regimens represents a non-toxic, readily achievable treatment procedure that has the potential to strengthen effective protocols for the treatment of cancer.