(BALB/c X C57BL/6)F1 mice bearing an SV-40 fibrosarcoma in the limb were injected with 0.045, 0.09 and 0.18 microgram/g body wt actinomycin D into the tumour. Similar animals were also treated with local hyperthermia (39.7 degrees, 42.3 degrees and 43.6 degrees C intratumour temperature for 30 min). The marked increase in median survival time following the combination of drug and local hyperthermia indicates that the combined treatment has a synergistic effect in the control of solid tumours. The median survival time of animals receiving the two treatments in immediate succession was higher than in animals with 30 min between treatments. This has important implications for the therapy of human cancer
