Whole body hyperthermia is a therapeutic treatment, used since prehistoric times for the treatment of various conditions, including cancer. In some places, it is used as a treatment of cancer even today.
One research article (1) looked at whole body hyperthermia and the treatment of cancer. It noted that, in modern times, physicians and researchers have used whole body hyperthermia in the treatment of cancer, immunological diseases, viral disease, and other health conditions.
The researchers found that whole-body therapy destroyed cancer cells by inducing necrobiosis and apoptosis. Apoptosis is also known as programmed cell death. It also increased the effects of chemotherapy in combination with heat therapy. It allows for decreased doses of chemotherapy, decreasing the harmful effects to normal cells.
Source: 1.Suvervnev AV, et al. Whole Body Hyperthermia at 43.5-44°C: Dreams or Reality? Landes Bioscience; 2000-2013.