Hyperthermia’s side effects vary by type and treatment site. Most do not last long, but a small number of cases may be more serious. Actual risk should be assessed and explained by the care team based on individual circumstances.
What are common side effects of local hyperthermia?
According to the American Cancer Society (ACS), local hyperthermia may cause:
- Pain at the site
- Infection
- Bleeding
- Blood clots
- Swelling
- Burns or blistering
- Effects on skin, muscle, or nerves near the treated area
What are common side effects of whole-body or regional hyperthermia?
- Nausea
- Vomiting
- Diarrhea
More serious but less common side effects can include problems with the heart, blood vessels, or other organs. The National Cancer Institute (NCI) also notes that perfusion techniques can cause swelling, blood clots, bleeding, and other effects on normal tissue in the treated area, but most side effects improve after treatment.
Why might side effects appear only after treatment?
Because hyperthermia is often combined with chemotherapy or radiation therapy, ACS notes that side effects may appear alongside those treatments or emerge some time after treatment — which is why post-treatment observation and follow-up are important. See After Treatment for details.
The side effects above are summarized from U.S. public educational resources as a general overview, not a complete list of medical risks. The side effects that may actually occur, their likelihood, and their severity vary by the medical device used, the treatment site, and individual condition — refer to the approved manual of the specific medical device and your physician’s assessment.
Are these side effects serious?
Most side effects are mild and improve over time, but a small number of cases (such as heart or blood vessel issues), while uncommon, can be more serious. Actual risk assessment should be made by the care team based on the technique used, treatment site, and overall health, with full discussion before treatment.
Last updated: 2026-08-16 | Sources: American Cancer Society (ACS), “Hyperthermia to Treat Cancer” (updated 2025-04-07); National Cancer Institute (NCI), “Hyperthermia to Treat Cancer” (updated 2025-05-15). If content differs from the latest research, the latest publicly available information takes precedence — please also consult your care team.