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It is quite likely that many cancer patients did not even heard about hyperthermia therapy. Although the method is not new, its popularity as well as effectiveness is limited. But some interesting recent scientific developments may pave the way to the renaissance of this slightly ignored cancer treatment technique.
What is hyperthermia therapy and how it works?
The term “hyperthermia therapy” refers to a type of medical treatment when the whole body or a part of body is exposed to elevated temperature for some period of time.
Although general hyperthermia was regarded as a good therapy from ancient time, its specific effect on cancer was scientifically documented only in 19th century. It was noticed that cancer patients who experienced high fewer due to additional infectious diseases experienced a reduction of the tumor size.
What stands behind this effect?
Cancer cells are not more sensitive to the heat than normal ones. The difference originates in the disorganized vascular structure of tumors. Due to the fast growth of tumor, blood vessels within it are not properly formed. This fact has two important consequences.
- First, tumors are deprived of adequate oxygen supply (the effect known as hypoxia).
- Second, they can’t easily dissipate heat and become overheated easier than surrounding tissues.
Overheating of tumor can lead to a variety of effects. If temperature has risen too much and too fast, some proteins in the cancer cells become denatured and this causes cell death. At lower temperature, specific heat shock proteins get activated. These proteins trigger apoptosis – a programmed death of the cell. Apoptosis is a suicide program which gets activated in response to a variety of external and internal stimuli. Essentially, everything what can potentially cause severe malfunctioning of the cell (physiological stress, excessive level of damage, mutations) can lead to apoptosis. Apoptosis is a highly organized mode of cell’s self-destruction, which does not damage surrounding cells and tissues.
Effectiveness of hyperthermia
Hyperthermia therapy, unfortunately, is simply not good enough to achieve cancer removal or reduction of its size on its own. However, the use of hyperthermia helps to enhance the effectiveness of other anti-cancer treatments. For instance, hyperthermia can increase the impact or radiotherapy and chemotherapy.
Radiotherapy alone achieves complete response only in 30% of cases. Complete response to any anticancer treatment is defined as an absence of visible signs of tumor. This doesn't mean tumor is completely eliminated – some cancer cells usually survive and can re-initiate the growth of tumor at a later stage. Nevertheless, achieving complete response significantly improve the survival rate of cancer patients.
This is up to three times higher response rate compared to the use of irradiation alone. The 5-years survival rates were 80% for patients with breast cancers, 88% for patients with head and neck cancer and 87% for patients with prostate cancer.