Three experimental solid tumors of common origin and transplantation site but with widely differing growth-rate, histopathologic, and cell kinetic characteristics have been selected for comparative studies of their response to X irradiation. The volume-doubling times for hepatomas H-4-II-E, 3924A, and 16 are 49, 96, and 587 hr, respectively, and the cell cycle times determined for the three tumor lines are 39.1, 27.9, and 331.9 hr, respecively. The responses of all three tumors have been assayed by relative changes in tumor volume. Each of the tumors responds to a single exposure of 1500 R, with the initial radiation-induced perturbation of growth linked primarily to the respective cell cycle times. After some delay, the growth rate of hepatoma 3924A returned to control values, while hepatoma H-4-II-E grew more slowly. The slowly growing hepatoma 16 remained perturbed for at least 80 days postradiation. A comparison of the results for the rapidly growing tumors treated with 3750 R suggests that prediction of tumor response to radiation requires an understanding of both cell production and cell loss from the tumor as well as the histopathology and relative tissue composition of the tumor. These results are discussed in regard to the radiosensitivity and radioresistance of solid tumors.

This content is only available as a PDF.
You do not currently have access to this content.