Life-span and cancer: the induction time of tumors in diverse animal species treated with nitrosodiethylamine.

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