Bronchial dysplasia induced by radiation in miners exposed to 222Rn progeny.

OBJECTIVES To investigate whether sputum cytology can be used to monitor epithelial cell changes in groups at high risk of lung cancer from exposure to radiation. METHODS Dysplasia of bronchial cells was investigated by means of sputum cytology in a group of 434 underground miners. 100 of them were not exposed, and 334 were exposed to 222Rn progeny at cumulative exposures < 450 working level months. RESULTS The frequency of dysplasia in the exposed group was significantly higher than that in the not exposed group (P < 0.0001), and an exposure-response relation was found. This relation was different for smokers and non-smokers. CONCLUSIONS Possibly the frequencies of dysplasia could be used to assess past exposures of groups of miners. This approach could be applied to cases where data on radiation monitoring are not available or are very scarce.