Ultra low dose CT screen-detected non-malignant incidental findings in the Western Australian Asbestos Review Programme

Background and objective Computed tomography (CT)‐based studies of asbestos‐exposed individuals report a high prevalence of lung cancer, but the utility of low dose CT (LDCT) to screen asbestos‐exposed populations is not established. We aimed to describe the prevalence of indeterminate pulmonary nodules and incidental findings on chest LDCT of asbestos‐exposed subjects in Western Australia. Methods A total of 906 subjects from the Western Australian Asbestos Review Programme underwent LDCT of the chest as part of regular annual review. An indeterminate (solid) nodule was defined as >50 mm3 and part‐solid/non‐solid nodules >5 mm. The presence of asbestos‐related diseases was recorded with a standardized report. Results Subjects were mostly (81%) men with a median age of 70 years. Fifty‐eight (6.5%) participants were current smokers, 511 (56.4%) ex‐smokers and 325 (36.4%) never‐smokers. One hundred and four indeterminate nodules were detected in 77 subjects (8.5%); of these, eight cases had confirmed lung cancer (0.88%). Eighty‐seven subjects (9.6%) had incidental findings that required further investigation, 42 (4.6%) from lower airways inflammation. The majority of nodules were solid, 4–6 mm and more common with age. Five hundred and eighty (64%) subjects had pleural plaques, and 364 (40.2%) had evidence of interstitial lung disease. Conclusion The prevalence of LDCT‐detected indeterminate lung nodules in 906 individuals with significant asbestos exposure was 8.5%, lower than many other CT studies. Clinically important incidental findings were found in 9.4%, predominantly related to lower respiratory tract inflammation. LDCT appears to effectively describe asbestos‐related diseases and is likely to be an acceptable modality to monitor asbestos‐exposed individuals. The utility of low dose CT (LDCT) to screen asbestos‐exposed populations is not established. This study describes the incidental radiological findings from LDCT screening an asbestos‐exposed cohort. The prevalence of indeterminate nodules compared with other high‐risk populations appears low. LDCT appears effective in demonstrating other asbestos‐related diseases.