Introduction:
The aim of this study was to verify the presence of radioactive Polonium (Po-210) in the lungs of patients with lung cancer who were smokers, ex-smokers and never-smokers.

Methods:
Bronchial washing specimens of 55 patients diagnosed with non-microcytoma lung cancer (NSCLC), underwent alpha spectrometric analysis in order to detect the presence of Polonium 210 (Po-210) (primary end point). Patients were divided into 3 arms (smokers, ex-smokers, never-smokers). The detection of alpha radioactivity in urine and the detection of spirometric data were also performed (secondary end points). Each patient was then given a kit for the detection of the environmental Radon at home (for 3 months).

Results:
67 Bronchial washings were examined: 22 of smokers, 35 of ex-smokers and 10 of never-smokers. The Polonium was detected in 100% of the current smokers (mean 6 mBq) and of the ex-smokers (mean 4 mBq) bronchial washings, while it was detected only in 60% of the never-smokers bronchial washings. It is interesting that ex- smokers had quit smoking for at least 5 years. There were even 3 patients who quit 11, 17 and 20 years before. All patients presented a picture of chronic bronchitis or had a spirometry that could be classified as stage I or II GOLD. This suggests that heavy metal retention is more a function of mucociliary clearance than bronchial obstruction.

Conclusion:
The presence of Po-210 in the ex-smoker bronchial washings is an important finding both for understanding lung carcinogenesis and for health education and therapeutic recommendations.