Cancer Expert MD

Heat is one of the oldest ideas in cancer treatment, and one of the best tested. Hyperthermia raises the temperature of a tumor to roughly 40 to 44 °C (104 to 111 °F), usually for about an hour, at the same time as chemotherapy or radiation. At these temperatures heat does not burn the tumor away; it makes the cancer far more vulnerable to the treatments given with it. Large randomized trials in Germany and the Netherlands have shown that adding heat can improve survival. This article explains how hyperthermia works, the main types, and what the trials show.

Why Heat Hurts Cancer More Than Normal Tissue

Poor cooling. Tumors grow chaotic, leaky blood vessels. Normal tissue carries heat away by increasing blood flow; tumors cannot, so they heat up more and stay hot longer.

Broken DNA repair. Heat disables the proteins cancer cells use to repair DNA damage. Radiation and many chemotherapy drugs work by damaging DNA, so heat stops the cancer from undoing that damage.

More oxygen. Mild heat increases blood flow and oxygen in parts of the tumor. Radiation needs oxygen to work, so oxygen-starved areas that usually resist radiation become more sensitive.

More drug delivery. Heat increases the uptake and potency of drugs such as cisplatin inside cancer cells.

Immune signals. Heated cancer cells release heat shock proteins and other danger signals that can alert the immune system to the tumor.

The Main Types of Hyperthermia

Local and regional hyperthermia heats a tumor or an entire region of the body, such as the pelvis or abdomen, using radiofrequency or microwave antennas placed around the patient. Deep regional hyperthermia is the form tested in most of the major trials.

HIPEC (heated intraperitoneal chemotherapy) bathes the inside of the abdomen with heated chemotherapy during surgery, for cancers that spread across the abdominal lining.

Whole-body hyperthermia raises the temperature of the entire body, either to fever range or higher. It is offered in some German and other European clinics, and its evidence base is much smaller than for regional hyperthermia.

Thermal ablation is different: it uses temperatures above about 50 °C to destroy small tumors directly, as with radiofrequency or microwave ablation of liver tumors.

What the Randomized Trials Show

Soft tissue sarcoma (Germany-led European trial)

The landmark trial, led from Munich by Rolf Issels and run jointly by the European Organisation for Research and Treatment of Cancer and the European Society for Hyperthermic Oncology, randomly assigned patients with high-risk soft tissue sarcoma to chemotherapy with or without regional hyperthermia. Adding heat improved local control of the tumor, and the long-term results, published in JAMA Oncology in 2018, showed that patients who received hyperthermia lived longer, with the benefit still present at ten years.¹

Cervical cancer (the Netherlands)

The Dutch Deep Hyperthermia Trial randomly assigned patients with advanced pelvic cancers to radiation alone or radiation with hyperthermia. The largest benefit was in locally advanced cervical cancer: complete tumor disappearance rose from 57% to 83%, and three-year survival nearly doubled, from 27% to 51%.²

Ovarian cancer and HIPEC (the Netherlands)

In the OVHIPEC trial, published in the New England Journal of Medicine in 2018, women with advanced ovarian cancer undergoing surgery after initial chemotherapy were randomly assigned to surgery with or without heated chemotherapy in the abdomen. Those who received HIPEC lived nearly a year longer on average, with a median survival of about 46 months compared with about 34 months.³

Pancreatic cancer after surgery (Germany, 2023)

Not every setting has benefited. The German-led HEAT trial tested regional hyperthermia with cisplatin and gemcitabine after surgery for pancreatic cancer, compared with gemcitabine alone. It did not show a significant improvement in disease-free survival.⁴ As with every treatment, the benefit depends on the cancer and the setting.

Side Effects and Who Is a Candidate

Regional hyperthermia is generally well tolerated. The most common side effects are discomfort, sweating and fatigue during treatment, and occasional skin burns or areas of tender fatty tissue where the heat is applied. Metal implants in the treatment field and some heart conditions can limit eligibility, and whole-body hyperthermia places significant strain on the heart and circulation.

Where Hyperthermia Is Available

Regional hyperthermia is part of treatment at university hospitals and specialized centers in Germany, the Netherlands, Switzerland and Italy, and in parts of Asia. In the United States, regional hyperthermia is available at only a small number of centers, while HIPEC is more widely offered at major surgical centers. Our book, The New Reality of Cancer, has a chapter on heat, cold, light and sound therapies, explaining each type of hyperthermia, how it is combined with other treatment, and how patients find centers that offer it.

Frequently Asked Questions

Does hyperthermia work for cancer?

Randomized trials show that adding hyperthermia to chemotherapy or radiation improves survival in high-risk soft tissue sarcoma and locally advanced cervical cancer, and that heated abdominal chemotherapy (HIPEC) improves survival in advanced ovarian cancer.

Is hyperthermia used on its own?

Mild hyperthermia is used together with chemotherapy or radiation, because its main effect is to make those treatments work better. High-temperature ablation, a different technique, destroys small tumors directly.

How hot does hyperthermia get?

Regional hyperthermia heats the tumor to about 40 to 44 °C (104 to 111 °F), typically for about an hour per session.

What is the difference between hyperthermia and HIPEC?

Hyperthermia heats tissue from outside the body using energy waves. HIPEC circulates heated chemotherapy directly inside the abdomen during surgery.

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References

1. Issels RD, Lindner LH, Verweij J, et al. Effect of neoadjuvant chemotherapy plus regional hyperthermia on long-term outcomes among patients with localized high-risk soft tissue sarcoma: the EORTC 62961-ESHO 95 randomized clinical trial. JAMA Oncology. 2018;4(4):483–492.
2. van der Zee J, González González D, van Rhoon GC, et al. Comparison of radiotherapy alone with radiotherapy plus hyperthermia in locally advanced pelvic tumours: a prospective, randomised, multicentre trial. The Lancet. 2000;355(9210):1119–1125.
3. van Driel WJ, Koole SN, Sikorska K, et al. Hyperthermic intraperitoneal chemotherapy in ovarian cancer. New England Journal of Medicine. 2018;378(3):230–240.
4. Issels RD, Boeck S, Pelzer U, et al. Regional hyperthermia with cisplatin added to gemcitabine versus gemcitabine in patients with resected pancreatic ductal adenocarcinoma: the HEAT randomised clinical trial. European Journal of Cancer. 2023;181:155–165.

This article is for education only. It is not medical advice and does not diagnose or treat any condition. Cancer Expert MD has no financial relationship with any laboratory, drug maker, supplement company, clinic or hospital.