ANTICARCINOGENIC EFFECT OF TETRACHLORODECAOXIDE AFTER TOTAL-BODY GAMMA-IRRADIATION IN RATS

Tetrachlorodecaoxygen (TCDO) therapy of acute radiation syndrome was t ested for a possible influence on the development of X-ray-induced mal ignancies. BD IX rats were exposed to total-body irradiation (TBI, gam ma rays, 9 or 11 Gy) and received daily intravenous injections of eith er TCDO or physiological saline solution from days 4 through 11 after TBI. The short-term TCDO therapy reduced the acute death rate markedly , but survival rates after 4 months were similar with and without TCDO . The first malignancy after TBI occurred on day 103, and over the lif etime of the animals the tumor incidence in the group given TBI(11 Gy) without TCDO treatment was 73% vs 20% in animals with short-term TCDO therapy after TBI. In particular, there was a highly significant prev ention of radiation-induced leukemia [P (one-sided)< 0.001] by TCDO, a nd a significantly reduced incidence of malignant epithelial tumors [P (one-sided) < 0.05]. The development of sarcomas was not affected by TCDO. Long-term survival was not enhanced by TCDO due to the occurrenc e of bronchopneumonial infections about 1 year after TBI. In conclusio n, TCDO is not only a potent therapeutic agent in acute radiation synd rome, but it also significantly reduced the carcinogenic risk in rats after exposure to ionizing radiation.