Combined nitrogen mustard: radiation studies with a mouse tumor

The KHT sarcoma, growing in C3H mice, has been treated with nitrogen mustard and irradiation and the response studied as a function of time between the treatments. Two series of experiments have been done and they indicate that a greater response is observed if nitrogen mustard is given before irradiation than if it is given a few hours afterwards. A detailed analysis of the first series of experiments indicated that reoxygenation could occur after drug treatment (within 1 hour) and that at the dose level used (0.2 mg/mouse) nitrogen mustard treatment preferentially spared the hypoxic cells. Such an analysis has not been completed for the second series of experiments but there are some definite differences between the two groups of experiments, which seem to be due to a change in the response of the tumor to treatment with nitrogen mustard