When temperatures rise above 41°C (106°F), the heat starts to damage cells . How much damage is done depends on the temperature and how long the exposure lasts. The temperatures now used range from about 41 to 45°C (106 to 113°F).
Combining Hyperthermia with Other Therapies Heat is particularly effective when combined with radiation, for heat is especially destructive to two types of cells that tend to be resistant to radiation:
• cells making DNA in preparation for division; and
• cells that are acidic and starved for oxygen (poorly oxygenated). Unlike normal tissue , many tumors are likely
to have poorly oxygenated cells that are particularly susceptible to hyperthermia, and tumors can often be
heated to higher temperatures than surrounding normal tissues.
Heat also makes cells more sensitive to radiation by preventing them from repairing radiation damage. Heat
and radiation work best together when the two treatments are given simultaneously or within perhaps an hour
of each other. Hyperthermia treatments are usually given only once or twice weekly, because after cells are
exposed to heat, they become somewhat resistant to subsequent exposures for about three days.
Heat also seems to improve the effect of some of the drugs used in chemotherapy , such as bleomycin ,
cisplatin , cyclophosphamide , melphalan , mitomycin-C and the nitrosoureas .
