Background. Lung cancer was a leading cause of all cancer-related deaths among men and was strongly related to long-term tobacco smoking. Clinical staging of lung cancer was one of the most important prognostic factors: the higher prevalence of early detection of lung cancer, the better results of lung cancer treatment. The purpose of the study was to present morphological characteristics and additional findings in LDCT in males with a high risk of lung cancer.

Methods. We included 900 male subjects, residents in the Krakow area and its suburbs, who were current and former smokers between 50 and 74 years of age. Risk factors such as age, duration of tobacco use, exposure to asbestos, family history of non-malignant lung diseases, cancer and current respiratory symptoms were analysed for all participants. Pulmonary nodules detected in all participants in low-dose chest CT were classified into non-malignant, indeterminate and potentially malignant and all were classified into one of three groups of low (A), indeterminate (B) and high risk of lung cancer (C). Additional pulmonary findings detected in LDCT were also analysed.

Results. In 831 of subjects (92.3%) 4575 pulmonary nodules were detected, among which 66.6% (n = 3048) were solid, non-calcified. 47 potentially malignant nodules were revealed (1.5% of all solid non-calcified nodules). The oldest participants, who had the longest smoking duration were males with potentially malignant nodules. Additional pulmonary findings were revealed significantly more often among the high lung cancer risk group. Among 39 participants with potentially malignant pulmonary nodules, lung cancer was detected in 17.9% (n = 7) participants (0.78% of the study group).

Conclusions. Low dose chest computed tomography revealed 94.6% specificity. Statistically significant differences among participants from the high lung cancer risk group were found for median age, number of packyears, positive history of bronchitis, presence of emphysema, bronchiectasis, bronchial wall thickening, ground glass opacities and consolidations. Analyses of risk factors revealed statistically significant differences among those in a subgroup of histologically proven lung cancer, for median age over 60 years, duration of cigarettes smoking over 45 years (with number of packyears at least at the level of 37), mediastinal lymphadenopathy (especially of high grade) and GGOs (grounds glass opacities).