Hyperthermia. (Image credit: 荣智浩, CC BY-SA 4.0)
The body is made up of millions of cells and cancer starts when one of them instigates to develop and proliferate too much resulting to make a growth called tumour. Over the decades cancer shows high incidence of death and different therapy technique develop including radiotherapy and chemotherapy. However, recent discovery about hyperthermia technique which does not use any chemicals or damaging radiation to eliminate cancer cell with minimum injury to the normal cells. Hyperthermia (also known as thermotherapy) is generally regarded as a mean body temperature higher than normal (Alexander, 2008). Research has shown that elevated body temperature can damage and kill cancerous cells with minimal injury to normal cells (van der Zee et al., 2000).
Hyperthermia causes tumor cell more susceptible to radiation and injure other cancer cells. The study focuses on the use of heat to treat cancer and it is generally applicable to any other forms of cancer therapy. Hyperthermia also intends to cure various types of cancer including lung, liver, brain, esophagus, breast, bladder and rectum. According to GLOBOCAN statistics analysis (2012) there are 14.1 million new cancer cases, 8.2 million cancer deaths and 32.6 million people living with cancers. There are different types of hyperthermia technique that are presently studied including local, regional and whole body hyperthermia. All of these technique show significant depression in tumor size combining with other therapy.
It is a technique that the heat applied only to the small fraction of the tumor tissue by using applicator emitting microwaves or antennas or radiowaves to locate the specific target area that can be heated in the surface with the contacting medium. There are different form of applicators used clinically such as waveguide applicators, horn spiral, compact applicator and current sheet. For local hyperthermia intra-tumoral temperature can be controlled by the applicators providing its specified location. On the other hand there are some side effects of local hyperthermia thus includes bleeding, pain to the target site, swelling, burns, blood clots and blistering as well as injuring the nerves and muscles roughly at the treated area.
In regional hyperthermia a body part such as organ, limbs and body cavity is heated using arrays of antennas with different applicators like sigma blade that is broadly used containing four pairs of dipole antennas. Endocavitary hyperthermia is useful for the tumors less than 5 cm in diameter and it is effective to administer along with brachy therapy. There are several antenna types used such as radiofrequency electrodes, ultrasounds transducers, microwave antennas, heat sources (hot water tubes, ferromagnetic seeds) and fibers. This technique is a bit painful since the positioning of the applicators is not more than 1.0-1.5 cm and the sensitivity to interference, positioning of the antennas and orientation is critical. The antennas inserted in the hollow organ that includes rectum, esophagus, cervix, urethra and vagina and on the outside of the body a counter electrodes applied to generate power deposition surface.
Whole Body Hyperthermia
The hyperthermia is administer to treat metastatic tumor that is already multiply throughout the body wherein a fixed state of 42 °C is uphold for 1 hour with tolerable adverse effects and with the help of general anesthesia the procedure would be possible. A person weigh about 70kg at 37 °C has a basal metabolic rate of 85 W which is double for 42 °C. The applicator used is sigma-Eyed applicator that consists of three shorter rings with four flat dipole antenna pairs. Side effects of whole body hyperthermia include vomiting, diarrhea and nausea. In rare cases it leads to the problem in blood vessels and some major organs.
Nowadays hyperthermia becomes a vital treatment modality in curing of cancer since it shows significant results supported by evidence. Hyperthermia is very important in addition to radiotherapy either with or without chemotherapy to treat advanced or high-risk tumors as well as to draw back the relapse of pre-irradiated area. Hyperthermia is the latest and become the fourth pillar to treat cancer along with surgery, radiotherapy and chemotherapy. Therefore it is looking forward to fight one common enemy wherein four weapons are better than three.
Source: ELSEVIER: Achievements in Life Science. Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University