Response of mouse sarcoma- 180 to bleomycin in combination with radiation and hyperthermia

The response of a transplantable mouse tumor, S-180, grown intradermally in inbred Balb/c mice, to bleomycin (BLM), irradiation (RT) and hyperthermia (HT) was studied by observing tumor growth changes up to 120 days after treatment. BLM, at 20 mg/kg body weight, and 10 Gy gamma radiation individually produced identical tumor cure, while hyperthermia at 42°C, 60' or 43°C, 30' resulted in a higher tumor response. Treatment with 43°C, 30' after BLM was more effective than hyperthermia after radiation in effecting tumor cure as well as in inducing regrowth delay. In the drug + HT combination the low drug dose was almost equal in effect as the higher drug dose when followed by 43°C, 30'. Combining the three modalities resulted in 100% tumor cure without any local recurrence during the observation period. The micronucleus study 24 h after treatment indicated enhanced cytogenetic damage by the combination treatments.