Evidence of cancer risk from experimental animal radon studies

Abundant epidemiological data from underground miners confirm that radon decay products are carcinogenic, although the evidence is less conclusive on the quantitative risks of these exposures, especially for indoor air. Experimental animal studies, in conjunction with dosimetric modeling and molecular/cellular level studies, are particularly valuable for understanding the carcinogenicity of human radon exposures and on the modifying effects of exposed rate, the physical characteristics of the inhaled decay products, and associated exposures, such as to cigarette smoke. The similarities in the animal and human data presently outweigh the differences between them, including comparable lung cancer risk coefficients, tumor-related dosimetry, and tumor pathology. The animal models, therefore, appear to be reasonable surrogates for studying the health effects of human radon exposures