Prevalence and features of pleural abnormalities in lung cancer screening trial: relation with asbestos exposure and risk of lung cancer

Objectives: To describe pleural findings in lung cancer screening participants, to compare asbestos–related pleural findings with self-reported asbestos exposure, and to evaluate relation with lung cancer. Methods and Materials: Pleural abnormalities were reviewed in 2301 baseline low-dose computed tomography (LDCT) and divided into two categories: “specific” associated to pleural plaques or diffuse pleural thickening, and “unspecific” if otherwise. Pleural abnormalities (Figure 1) and concomitant parenchymal findings (Figure 2) were visually scored. Self- disclosure of asbestos exposure was collected. Frequency of lung cancer was detailed according to presence of pleural findings. Statistical analyses included comparison of mean or median, contingency tables, and odds ratio (OR) of lung cancer. Results: 193/2301 (8.4%) participants showed pleural abnormalities, with 27/2301(1.2%) subjects with specific and 166/2301(7.2%) with unspecific pleural findings. 42/193(21.2%) showed parenchymal abnormalities, with positive association to specific pleural findings (p=0.02). 150/2301(6.5%) subjects disclosed asbestos exposure, with the highest frequency in subjects with specific pleural findings (6/27; 22.2%). Frequency of lung cancer was similar between subjects with or without pleural abnormalities (p=0.39). Lung cancers were 2/27(7.4%) in subjects with specific and 5/166(3.0%) with unspecific pleural findings (p=0.31). Parenchymal abnormalities were significantly associated with risk of lung cancer (OR 12.42). Conclusion: Risk of lung cancer was not related to pleural abnormalities, either specific or unspecific. Parenchymal abnormalities were a risk factor for lung cancer among subjects with pleural abnormalities. The majority of subjects with specific pleural findings were not aware of asbestos exposure. LDCT findings should be integrated in models of lung cancer risk.