By Dr. Allison Gandre, ND | Elevate Health
Cancer treatment works best when we understand what makes cancer cells vulnerable—and how different therapies can work together. Medical-grade local and regional hyperthermia (HT) brings a powerful tool to that effort: carefully controlled heat.
Hyperthermia can directly damage cancer cells, trigger programmed cell death, and interfere with the repair mechanisms that help tumors survive treatment. Research also shows that heat can influence the immune response within a tumor, creating promising opportunities to strengthen cancer care.
My interest is both professional and personal, shaped by encouraging responses in my patients and my own father’s experience incorporating hyperthermia into his prostate cancer care.
What is medical hyperthermia?
Local hyperthermia targets a specific tumor, while regional hyperthermia heats a larger treatment area. Specialized equipment delivers energy to the tissue, with the approach selected according to the tumor’s location and depth.
Nonablative hyperthermia uses controlled heating below the temperatures used for thermal ablation. Nonablative does not mean that it cannot kill cancer cells. It means the treatment does not aim to destroy the entire targeted tissue volume through high-temperature ablation. Hyperthermia can damage and kill cancer cells while also making other treatments more effective. [1]
What does heat do to cancer cells?
1. It can trigger apoptosis—programmed cell death
Apoptosis is a regulated process through which a cell dismantles itself. Cancer cells often develop ways to evade this process.
Sufficient thermal stress can activate pathways that bring apoptosis back into play. In laboratory studies of human osteosarcoma cells, heating to 43°C for 60 minutes triggered apoptosis through oxidative stress and stress within the endoplasmic reticulum—the cellular structure involved in protein production and processing. [2]
This demonstrates that heat itself can destroy cancer cells. The extent of that effect depends on the temperature achieved within the tumor, how long it is maintained, and the cancer’s biology. Laboratory results help explain the mechanism; they do not predict how much of an individual patient’s tumor will be destroyed.
2. It interferes with cancer cells’ ability to repair damage
Cancer cells rely on DNA repair systems to recover from treatment. Hyperthermia can disrupt those defenses.
Research has shown that mild hyperthermia can degrade the BRCA2 protein and inhibit homologous recombination, an important DNA repair pathway. With that repair pathway impaired, cancer cells can become more vulnerable to therapies that damage their DNA. [3]
This is one reason timing and coordination matter: combining heat with another treatment can create an opportunity to damage cancer cells while their defenses are weakened.
3. It can change blood flow and oxygen availability
A solid tumor contains a complex environment of cancer cells, blood vessels, connective tissue, and immune cells. Some regions receive little oxygen, which can make them more resistant to radiation.
Experimental studies show that mild hyperthermia can increase tumor blood flow and improve oxygenation under appropriate conditions. This provides another explanation for how heat can support radiation treatment. The response varies with temperature, timing, and the tumor’s blood vessels. [4]
How does hyperthermia affect the immune system?
One of the most exciting areas of research is how heat changes the interaction between a tumor and the immune system.
Helping immune cells recognize cancer
Natural killer—or NK—cells help identify and destroy abnormal cells. In experimental colon cancer models, mild thermal stress increased the expression of a stress-related signal called MICA, making certain tumor cells easier for NK cells to recognize and attack. [5]
That finding points to an important possibility: heat can affect both cancer cell survival and the signals that reveal cancer cells to immune defenses.
Encouraging immune activity within the tumor
Dendritic cells help coordinate immune responses by presenting information about abnormal cells to T cells.
In a mouse breast cancer study, local hyperthermia delivered through near-infrared heating was associated with more activated dendritic cells in nearby lymph nodes and greater infiltration of T cells and NK cells into tumors. Researchers also observed changes in immune signaling consistent with a more active antitumor response. [6]
These findings provide a promising foundation for studying hyperthermia alongside immunotherapy. Much of the detailed immune evidence remains preclinical, and different heating methods are not interchangeable. The clinical question is how to translate these biological effects into reliable improvements for patients.
Does this translate into better outcomes?
For selected cancers and treatment combinations, randomized trials show that it can.
In patients with localized, high-risk soft tissue sarcoma, adding regional hyperthermia to chemotherapy improved local progression-free survival. Long-term follow-up also reported improved survival in that study population. [7]
In a randomized study of advanced pelvic tumors, the cervical cancer subgroup had a complete response rate of 83% with radiation plus hyperthermia, compared with 57% with radiation alone. These results support the value of adding heat in that setting, although the trial predates current chemoradiation practice. [8]
These studies give us concrete reasons for optimism. They also show why treatment selection matters: benefits depend on the cancer type, heating system, thermal dose, and accompanying treatment.
What I see in clinical practice
At Elevate Health, I have regularly observed decreases in tumor size and SUV activity on PET scans in patients receiving hyperthermia within their broader cancer care plans.
Those changes are encouraging and give us measurable findings to follow. They are clinical observations rather than controlled research, and combined treatment makes it difficult to determine the contribution of HT alone.
That is why we follow the whole clinical picture: imaging, symptoms, laboratory findings, and the oncology team’s assessment. The goal is meaningful disease control and better outcomes for the person receiving care.
Bringing the science into an individualized plan
Effective hyperthermia requires more than a sensation of warmth. Treatment planning must account for tumor depth, the equipment’s capabilities, the temperature and duration of heating, and coordination with other therapies.
Careful monitoring also matters. Local and regional hyperthermia can cause pain, hot spots, blistering, or burns if the tumor site is close to the surface of the skin. Specialized delivery helps manage these risks while targeting an effective treatment. [1]
The science offers a compelling reason to keep advancing this work: heat can attack cancer cell survival mechanisms, strengthen established treatments, and influence the immune environment around a tumor. With thoughtful patient selection and coordinated care, hyperthermia offers an evidence-supported opportunity to improve treatment response in selected solid tumors—and a promising direction for continued progress.
References
- National Cancer Institute. Hyperthermia to Treat Cancer. Reviewed May 15, 2025. Read overview.
- Hyperthermia Induces Apoptosis through Endoplasmic Reticulum and Reactive Oxygen Species in Human Osteosarcoma Cells. International Journal of Molecular Sciences. 2014;15(10):17380–17395. Read study.
- Krawczyk PM, et al. Mild hyperthermia inhibits homologous recombination, induces BRCA2 degradation, and sensitizes cancer cells to poly (ADP-ribose) polymerase-1 inhibition. PNAS. 2011;108(24):9851–9856. Read study.
- Tumour oxygenation is increased by hyperthermia at mild temperatures. Experimental research. Read study.
- Enhanced Sensitivity of Colon Tumor Cells to Natural Killer Cell Cytotoxicity after Mild Thermal Stress Is Regulated by HSF1-Mediated Expression of MICA. Preclinical research. Read study.
- Hyperthermia by near infrared radiation induced immune cells activation and infiltration in breast tumor. Animal research. Read study.
- Issels RD, et al. Effect of Neoadjuvant Chemotherapy Plus Regional Hyperthermia on Long-term Outcomes Among Patients With Localized High-Risk Soft Tissue Sarcoma. JAMA Oncology. 2018;4(4):483–492. Read study.
- van der Zee J, et al. Comparison of radiotherapy alone with radiotherapy plus hyperthermia in locally advanced pelvic tumours: a prospective, randomised, multicentre trial. The Lancet. 2000;355:1119–1125. Read study.
