Interactions between polonium-210 alpha-radiation, benzo(a)pyrene, and 0.9% NaCl solution instillations in the induction of experimental lung cancer.

Benzo(a)pyrene and 210Po were administered both simultaneously and sequentially by intratracheal instillations to Syrian golden hamsters in experiments designed to identify any synergistic interactions between these carcinogens. Their effects were additive after simultaneous administration. A significant synergistic interaction between the two agents appeared to occur when benzo(a)pyrene exposure followed 4 months after 210Po exposure. Most of this effect could be ascribed, however, to a potentiating effect of subsequent 0.9% NaCl solution instillations on 210Po carcinogenesis. These results emphasize the fact that seemingly innocuous stimuli may significantly potentiate lung carcinogenesis. The implications of these findings in terms of the interactions between alpha-radiation and cigarette smoke in human populations are discussed.