Fractionated thermochemotherapy in vivo of a C3H mouse mammary carcinoma.
The interaction between fractionated heat treatment and fractionated drug treatment with cyclophosphamide (CTX) was investigated in a transplantable C3H mouse mammary carcinoma inoculated into the hind leg of C3D2F1/Bom mice. A tumour core temperature of 43.5 +/- 0.1 degrees C was achieved by immersing the tumour-bearing leg into a water bath thermostatically maintained at 43.7 +/- 0.1 degrees C. CTX was administered i.p. using the maximum tolerated dose (MTD) (LD 1%) for single fraction treatment (100 mg/kg) as the maximum fraction dose. For combined treatment CTX was given 15 min prior to heating. The endpoint was the time to reach a tumour volume of 5 times the volume at first treatment. Specific growth delay was used as effect parameter. In dose-effect experiments using total treatment time at 43.5 degrees C as dose parameter, drug enhancement ratio (DER) was determined as the ratio of the slope of the dose-effect curve for MTD of CTX plus heat to the slope of the curve for heat alone. In dose-effect experiments using total CTX dose as dose parameter, thermal enhancement ratio (TER) was determined as the ratio of the slope of the dose-effect curve for CTX plus 43.5 degrees C for 30 min to the slope of the curve for CTX alone. The regimens investigated were single fraction treatment and 3 and 5 fractions with time intervals of 3 and 5 days. For single fraction treatment DER was 1.4 +/- 0.1 and TER 2.3 +/- 0.2. The drug sensitization of the effect of heat treatment tended to increase with increasing number of fractions.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Medical Oncology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo.
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OR
Monge
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Rofstad
D000818:Animals; D001494:Baths; D005591:Chemical Fractionation; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use*; D006979:Hyperthermia, Induced / Q000379:methods; D008325:Mammary Neoplasms, Experimental / Q000532:radiotherapy* / Q000628:therapy; D051379:Mice; D008809:Mice, Inbred C3H
D003520:Cyclophosphamide