Search

Heart lesions similar to those seen in patients who have undergone thoracic radiotherapy were produced in young rabbits by a single 2,000-rad dose. Myocardium was studied during the latent period (two to seventy days) by light microscopy of 1μ epoxy sections, electron microscopy, and 3H-TdR radioautography. Endothelial cell damage, capillary narrowing, and microthrombi were seen at several points. Myocytes showed little damage. Endothelial cells were often 3H-TdR-labeled, while myocytes were not. Between thirty-nine and seventy days, labeled cells of irradiated myocardium increased significantly in number. In the late stage the ratio of capillaries to myocytes was reduced.

The authors analyzed treatment results in 71 cases of Wilms's tumor. The abdominal control rate was higher in 42 patients receiving postoperative radiotherapy (85.5%) than in 6 patients not receiving such therapy (1/6). In patients treated by nephrectomy and postoperative radiation, the addition of chemotherapy improved survival (78.2 VS. 30%). Pulmonary metastasis did not necessarily denote a hopeless situation since a significant number of patients could be salvaged by concurrent radiotherapy and chemotherapy; higher control rates were achieved with total than with less-than-total thoracic irradiation. Relatively low-dose irradiation appeared sufficient in both abdominal and thoracic radiotherapy if chemotherapy was given concurrently.