Objectives To evaluate whether the presence of pleural abnormalities was a reasonable marker to predict mesothelioma among workers with asbestosis in Hong Kong.

Method This is a historical cohort study comprised of 99 male asbestosis workers registered in the Pneumoconiosis Clinic under Hospital Authority of the Hong Kong Government during 1981–2008 who had records of chest radiograph at the time of diagnosis of asbestosis. All asbestosis workers were followed up till 31/12/2008 and the rate of follow-up was 97%. We calculated the sensitivity and specificity of the presence of benign pleural abnormalities (i.e., the presence of benign plaques and/or thickenings at the initial chest radiograph)” using mesothelioma deaths as the “good standard”; meanwhile, the positive predictive value (PPV) and negative predictive value (NPV) were also calculated.

Results Benign pleural abnormalities appeared in the initial radiograph for 54 asbestosis workers. We observed 15 mesothelioma deaths and 4 of them had benign pleural abnormalities at the initial chest radiographs. The sensitivity, specificity, PPV, and NPV for using the baseline benign pleural abnormalities to predict mesothelioma deaths was 0.27 (95% CI: 0.078–0.55), 0.63 (95% CI: 0.52–0.73), 0.11 (95% CI: 0.032–0.27), and 0.83 (95% CI: 0.71–0.91). These results remained unchanged when workers with co-presenting cancer at the baseline were excluded from the analyses.

Conclusions This study suggests a relatively limited value for using benign pleural abnormalities as markers to predict mesothelioma deaths in workers with asbestosis. [Acknowledgement: CUHK Direct Grant (Project code.: 2041587), Hong Kong]