Enhancement of Hyperthermia on Anti-tumor Drug Sensitivity

Anti-tumor drugs have been utilized in combination with hyperthermia, synergistic effects have been observed, and efforts have been made to explain the basis for these observations. It is thought that the initial extent of DNA damage is enhanced by hyperthermia effects, and this outcome is associated with tissue blood flow. If this is true, then an associated effect would be an additional increase in DNA damage induced by anti-tumor drugs. Another hypothesized mechanism is that DNA repair enzyme activity required for repair of DNA damage is depressed by a heat exposure. A third hypothesis is that more efficient cell killing is induced by the induction of cell death signaling pathways and the depression of cell survival signaling pathways through hyperthermia (Fig. 10.1). In this chapter, the main focus is on the increase in activity of anti-tumor drugs induced by hyperthermia. DNA repair inhibition induced by hyperthermia has been described in other chapters.