Asbestos exposure, pleural plaques, and the risk of death from lung cancer.

Abstract

Although asbestos is a well-known lung carcinogen, the pleural plaque-lung cancer link remains controversial. This study was designed to examine this link in asbestos-exposed workers. A 6-year follow-up was conducted to study lung cancer mortality in the 5,402 male subjects participating in an asbestos-related disease screening program conducted from October 2003 to December 2005 in four French regions. Chest computed tomography (CT) scan was performed in all subjects with randomized, independent, double reading of CT scans focusing on benign asbestos-related abnormalities. Cox model survival regression analysis was used to model lung cancer mortality according to the presence of pleural plaques, with age as the main time variable, adjusting for smoking and asbestos cumulative exposure index. All statistical tests were two-sided. Thirty-six deaths from lung cancer were recorded. Lung cancer mortality was significantly associated with pleural plaques in the follow-up study in terms of both the unadjusted hazard ratio of 2.91 (95% confidence interval = 1.49-5.70) and the adjusted hazard ratio of 2.41 (95% confidence interval = 1.21-4.85) after adjustment for smoking and asbestos cumulative exposure index. Pleural plaques may be an independent risk factor for lung cancer death in asbestos-exposed workers and could be used as an additional criterion in the definition of high-risk populations eligible for CT screening.