Modification of radiation injury to normal tissues by chemotherapeutic agents.

The effects of several cancer chemotherapeutic agents on radiation damage to normal intestine, esophagus, and lung tissue were evaluated in LAF 1 mice using quantitative endpoints. In all tissues tested, actinomycin D increased injury and BCNU did not. In the intestine, adriamycin enhanced radiation damage more than any other agent. Bleomycin increased damage in the esophagus but not in the lung or intestine. Cyclophosphamide increased injury only in the lung, where vincristine caused minimal injury, and hydroxyurea, none. Only prednisolone caused significant radioprotection when given at the time of irradiation or at the time of expected death from pulmonary injury.