Hyperthermia: Cancer Treatment

Introduction

Generally, hyperthermia increases the efficacy of radiation treatment by around 50% when compared to radiation alone. As a cancer treatment, hyperthermia, or heat therapy, is used because the heat is believed to decrease tumours. Heat prevents these cells from receiving the nutrients they require to survive. 

Hyperthermia is not a common therapy for cancer. It is often used as an adjunct to other therapies, and enhances the effectiveness of other cancer therapies such as radiation therapy and chemotherapy. In rare instances, intense heat may eradicate all cancer cells. However, this also kills or damages healthy cells and tissue.

Hyperthermia treatment

Hyperthermia as a cancer treatment is not generally accessible. In certain institutions, however, it is used in conjunction with radiation therapy and chemotherapy to treat advanced tumours. It has been used to treat appendix, bladder, brain, breast, cervical, oesophageal, head and neck, liver, lung, melanoma, mesothelioma, sarcoma, and rectal cancers.

Hyperthermia is a method of therapy in which bodily tissue is heated to temperatures as high as 45°C (113°F) to destroy and kill cancer cells while causing little or no damage to healthy tissue. Cancer treatment using hyperthermia is also known as heat therapy, thermal ablation, and thermotherapy. 

Various approaches may be used to generate heat for hyperthermia therapy. These techniques include probes that generate energy from microwaves, radio waves (radiofrequency), lasers, ultrasound, heating fluids such as blood or chemotherapy drugs and injecting them into the body (perfusion), placing the entire body in a heated chamber or hot water bath, or wrapping with heated blankets. 

How does hyperthermia treat cancer?

Hyperthermia is almost usually combined with other cancer treatments. Numerous clinical investigations have shown that hyperthermia, when combined with therapies such as radiation therapy and chemotherapy, aids in the reduction of tumour size and may make it simpler for these therapies to eliminate cancer cells. 

During therapy, the physician anaesthetizes the affected region and inserts thermometer-equipped probes into the tumour. During therapy, thermometers allow the physician to precisely monitor the temperature of the tumour and surrounding tissue. It is possible to employ imaging methods, such as CT scans, to ensure that the probes are in the correct location.

Types of hyperthermia cancer treatments

Hyperthermia may be used to treat both tiny and big parts of the body, as well as the complete body. 

Local hyperthermia

Local hyperthermia is the application of heat to a limited region. This therapeutic modality targets a single tumour or other tiny locations. The heat is administered externally and directed towards the tumour. It may also be heated from inside the body. This is accomplished using a tiny, heated wire probe. Radiofrequency ablation is an interstitial hyperthermia technique that uses radio waves to heat and destroy cancer cells. The kind of local hyperthermia used depends on the location of the tumour: 

• External hyperthermia is used to treat skin or superficial subcutaneous malignancies by using heat-generating devices around or near the treatment site
• Intraluminal or endocavitary hyperthermia is used to treat cancers inside or near bodily cavities, such as the oesophagus or rectum. In this kind of hyperthermia, surgeons introduce probes that generate heat into the cavity of the tumour
• Interstitial hyperthermia is used to treat deep-seated cancers, such as those in the brain. Under anaesthesia, the doctor will introduce probes or needles into your tumour. The probe is then put into the heat source

Regional hyperthermia

Regional hyperthermia involves the application of heat to significant regions of the body, such as a cavity, organ, or limb. Deep tissue methods, regional perfusion, and continuous hyperthermic peritoneal perfusion are used in regional hyperthermia.

• Internal malignancies, such as cervical and bladder cancer, are treated using deep tissue procedures. During this technique, heat-delivering devices are positioned around the cavity or organ to be treated, and energy is concentrated on the region to elevate its temperature
• Regional perfusion methods are used to treat tumours in the arms and legs, such as melanoma, as well as in some organs, such as the liver and lungs. During this operation, a portion of your blood is withdrawn, heated, and then reinjected into the affected limb or organ. Chemotherapy is often used during this treatment
• Continuous hyperthermic peritoneal perfusion is a treatment for cancer of the abdomen. This therapy is administered during surgery. While you are under anaesthesia, chemotherapy medications heated by a warming device flow into the abdomen

Whole-body hyperthermia

Malignancy that has spread throughout the body is treated with whole-body hyperthermia, in which the whole body is heated. Your physician may use warm water blankets. You may also be put in a thermal chamber or room. In this kind of hyperthermia, you are put in a thermal chamber or covered in hot water blankets for brief periods of time to increase your body temperature to 42°C (107 or 108°F).

Risks and benefits of hyperthermia treatment 

Hyperthermia treatment needs specialised equipment and knowledge and is not commonly accessible. If the temperature remains below 44℃ (111°F), the majority of healthy tissue is not harmed by hyperthermia. However, varied characteristics of certain tissues may generate elevated temperatures in specific locations. This may result in burns, blisters, distress, or pain.

Perfusion procedures may result in oedema, blood clots, haemorrhage, and other harm to the treated area's normal tissues. The majority of these adverse effects, however, improve with therapy. Normal symptoms of whole-body hyperthermia include diarrhoea, nausea, and vomiting. It may also induce uncommonly severe adverse effects, including heart and blood vessel disorders. 

Local hyperthermia has negative side effects, such as:

• Infection 
• Bleeding 
• Blood clots
• Swelling 
• Burning 
• Blistering 
• Skin, muscle, and nerve damage around the treated region

Other major but uncommon adverse effects of localised and whole-body hyperthermia therapy include: 

• Heart difficulties 
• blood vessel concerns 
• Major organ issues

There are several advantages to heat treatment. Hyperthermia may improve the efficacy of other cancer therapies, such as chemotherapy and radiation therapy. This therapy is effective for tumours that have been previously treated with radiation. This cancer therapy has the advantage of being able to precisely target your body's temperature. The body's response to hyperthermia therapy is an additional advantage. When you undertake this therapy, your immunological response is enhanced. Still, ongoing clinical studies investigating the effects of heat and immunotherapy.

The future of hyperthermia treatment for cancer

Hyperthermia is a potential method for enhancing cancer therapy. However, it is still primarily experimental at this moment. It needs specialised technology, as well as a qualified physician and treatment team. Therefore, it is not available at all cancer treatment clinics. Numerous clinical studies of hyperthermia are now being conducted to further comprehend and advance this method. 

Presently, commercially accessible hyperthermia devices are capable of delivering heat effectively to several tumour locations.9 Hyperthermia may also greatly increase the efficacy of both radiation and chemotherapy, resulting in dramatically better tumour control and extended disease-free life. In addition, hyperthermia accomplishes so without increasing radiation exposure or chemotherapy-related adverse effects.¹

Summary

Hyperthermia is a cancer therapy in which tissue is heated to temperatures as high as 45°C (113°F) in order to destroy and kill cancer cells while inflicting little or no harm to healthy tissue. There are several ways to create heat for hyperthermia treatment. These include probes that create energy via the use of microwaves, radio waves, lasers, ultrasound, and the heating of fluids such as blood and chemotherapeutic medicines. Hyperthermia may be used to treat both small and large body areas, as well as the whole body. However, it is still not widely available, and more clinical testing is needed until it becomes commonly adopted.