“…All resulted in an enhancement of the heat response. This outcome was time and schedule dependent, with the maximum response generally observed if the heat was started 1 to 6 hours after VDA administration (78,80,81,99,124,212,214,215), corresponding to the maximal reduction in blood flow in those studies. As to the exact mechanism responsible for this enhancement, there is evidence for both an improved tumor heating (78,124,214) and a decrease in tumor pH (124-127).…”