LIFE-SPAN AND CANCER - THE INDUCTION TIME OF TUMORS IN DIVERSE ANIMALSPECIES TREATED WITH NITROSODIETHYLAMINE

To ascertain the possible relationship between animal lifespan and the rate of tumor development, the results of carcinogenesis studies in v arious species treated with similar doses of a carcinogenic nitrosamin e have been compiled from the literature. Comparable experiments in 20 species of mammals, reptiles, birds, amphibians and fish were analyze d. The animals received approximately 1000 mg/kg body wt (400-2500 mg/ kg) lifetime total dose of nitrosodiethylamine (NDEA). Animals with li fespans varying from 3 years (mouse) to > 50 years (snake) developed t umors with latent periods of roughly 1 year (range 0.5-1.9 year), show ing no relationship to lifespan. The evidence suggests that the time d ependence of tumor development is more likely related to the cumulativ e dose of carcinogen than to lifespan and the rate of aging.