Asbestos exposure, pleural plaques and digestive cancers

The aim of this study was to analyse the incidence and mortality from various digestive cancer sites and their potential link with pleural plaques, in a French cohort of workers previously occupationally exposed to asbestos.

We conducted a 10-year follow-up study in 13,481 male subjects, included in the cohort between October 2003 and December 2005, for whom asbestos exposure was assessed by calculation of a cumulative exposure index (CEI) in equivalent fibres.years/mL for each subject. We conducted an incidence study and a mortality study. Complementary analysis was restricted to men who had performed at least one chest CT-scan (N = 4,794). We used a Cox model with age as the time axis variable, adjusted for smoking, time since first exposure (TSFE), CEI to asbestos and the existence of pleural plaques on CT-scan.

In the incidence study, a significant dose-response relationship was observed between CEI to asbestos and oesophageal cancer (HR 1.03, 95% CI [1.01-1.06]) in the entire cohort after adjustment for TSFE and smoking status. In subjects undergoing CT-scan, a significant association between pleural plaques was observed for oesophageal cancer incidence (HR 2.80, 95% CI [1.09-7.20]) and in the mortality study, multivariate analyses showed a significant dose-effect response between CEI to asbestos and death from oesophageal cancer (HR 1.03, 95% CI [1.00-1.05]) in the entire cohort.

This large-scale study confirms results concerning a likely relationship between asbestos exposure and oesophageal cancer, and the association between this cancer and pleural plaques after adjustment on CEI to asbestos.