The Response of Previously Irradiated Skin to Combinations of Fractionated X Radiation, Hyperthermia, and cis-Diamminedichloroplatinum

Abstract

Mouse legs were irradiated with a dose of 30 Gy. After 50 days, when the acute reaction had regressed to a steady state, they were retreated with either 30 Gy of X rays delivered in six fractions over 12 days, six exposures to hyperthermia for 45 min at 42.7 degrees C, six doses of cis-DDP, or a combination of these agents. The maximum skin reactions and the skin reactions integrated over 50 days were determined. The maximum skin response was found when the previously irradiated skin was treated with a combination of X irradiation and hyperthermia. The addition of cis-DDP to this regimen did not result in a further enhancement of the skin reaction. When the second treatment was irradiation alone or cis-DDP alone, the severity of the skin reactions was similar. Injury from the initial radiation dose persisted so that the cytotoxic action of cis-DDP resulted in a level of subacute skin damage that was similar to a second course of X irradiation.