Does Hyperthermia Work As An Anti-Cancer Treatment?

Based on an article titled “The role of hyperthermia in the treatment of locally advanced cervical cancer: a comprehensive review”

Originally written by: IJff et al., 2022

https://ijgc.bmj.com/content/early/2022/01/19/ijgc-2021-002473

By: Murielle Nsiela 

Introduction to hyperthermia treatment

Hyperthermia is when the body’s temperature is abnormally high¹. It is now used in combination with chemotherapy and radiotherapy to treat several tumour types, including; recurrent breast cancer, cervical cancer, head and neck cancer, bladder cancer, melanoma and soft tissue cancer². This technique uses temperatures above normal physiological levels (40-43°C ) for an hour³. This technique was first used by Frans Westermark in 1898 to treat cervical cancer. His son, Nils Westermark,  carried on the work and hypothesised that tumour tissues are sensitive to heat in comparison to healthy tissue⁴. 

How does it work?

Hypothermia treatment affects the cells and tissues in various ways such as altering the physical properties of the cell components, as well as its cellular responses. For example, hyperthermia treatment can alter the Deoxyribonucleic acid (DNA) repair process of tumours, hindering them from replicating. The treatment can also target cancer cells in the state where they do not have enough oxygen present (hypoxic state) and targets nutrient-deprived tumours where radiation and chemotherapy are less effective. Furthermore, hyperthermia can also alter the factors that are essential for tumour survival and growth, including the oxygen supply, microenvironment and immune responses ^5,3. 

The effectiveness of hyperthermia depends upon the temperatures used, the duration of the treatment, and the time intervals between the use of radiotherapy and hyperthermia. Evidence has suggested that applying radiotherapy and hyperthermia at the same time provides the best results. In addition, it has been suggested that the time interval between hyperthermia and ionising radiation should be as short as possible, within one hour. This is because longer intervals will prevent the inhibition of DNA repair due to the reduced effectiveness of hyperthermia ^6,4. Therefore, hyperthermia in combination with chemotherapy and radiotherapy has a synergistic effect instead of just an additional effect. 

Hyperthermia devices  

Hyperthermia devices used for deep-seated tumours, including cervical cancer, use electromagnetic energy, which can be divided into two systems- radiative and capacitive. Radiative heating devices are positioned around the patient’s pelvis, whilst capacitive heating devices use two electrodes placed in front of and behind the pelvis. It has also been suggested that achieving the targeted temperature for hyperthermia treatment is more challenging with the captive device than with the radiative device⁴.  

Results

Studies have compared treatment with chemoradiation alone and chemoradiation combined with hyperthermia; it was shown that the combination therapy had slightly better performance in comparison to the former. In other words, there were no significant differences in overall survival rates between the two treatment methods⁴. 

Some studies found that there has been no increase in toxicity when hyperthermia is added to the treatment. In contrast, others found some toxicity in palliative cancer patients⁷. Some studies reported that hyperthermia leads to late and acute toxicities, such as thermal burns, fat necrosis, and patient discomfort, which have all been considered hyperthermia-related toxicities⁸. However, with good quality assurance control, these toxicities can be limited. Furthermore, the treatment with hyperthermia is only contraindicated for patients with pacemakers and hip prostheses. This, therefore, makes this treatment method suitable for patients with advanced cervical cancer and other cancers⁴. 

Summary

In summary, treatment with cisplatin and radiotherapy is the standard treatment for advanced cervical cancer. However, the use of chemoradiation and the combination of hyperthermia and radiotherapy has proven to be a well-tolerated alternative treatment. In general, it should be provided to individuals who are contraindicated to have cisplatin. In addition, a good hyperthermia treatment should involve well-trained and experienced professionals, with the use of adequate hyperthermia devices with a good treatment plan and quality assurance.