Few studies have reported on
polonium-210, a decay breakdown product of
radon-222 and
lead-210, in human lungs and there has been no study in patients with suspected
lung cancer. The main aim of this "
Polonium in vivo" study was to evaluate
polonium-210 radioactivity in bronchopulmonary systems of smoker, ex-smoker and never smoker patients with suspected
lung cancer. Alpha-spectrometric analyses were performed on bronchial lavage (BL) fluids from two Italian hospitals in 2013-2016. Socio-demographic, smoking, occupational and spirometric characteristics,
lung cancer confirmation and histologic type and
radon-222 concentration in patients' homes were collected. Seventy BL samples from never (n = 13), former (n = 35) and current smokers (n = 22) were analyzed;
polonium-210 was detected in all samples from current and former smokers and in 54% of samples from never smokers (p < 0.001; median values: 1.20, 1.43 and 0.40 mBq, respectively).
Polonium-210 levels were significantly higher in
COPD versus no
COPD patients (median value: 3.60 vs. 0.97 mBq; p = 0.007); former and current smokers, without and with
COPD, had significantly increased
polonium-210 levels (p = 0.012); 96% of confirmed versus 69% of non-confirmed
lung cancer patients recorded detectable
polonium-210 levels (p = 0.018). A
polonium-210 detectable activity was measured in BL samples from all current and former smokers.
Polonium-210 in the lungs could be the result of
lead-210 entrapment, which, with its half-life of 22 years, could provide a continuous emission of alpha radioactivity, even many years after quitting, thus proposing a possible explanation for the onset of
lung cancer, particularly in former smokers.