Abstract
Asbestos-related diseases persist, because millions of workers have had prior exposure
and many industrializing countries continue to use asbestos. Globally, an estimated
107,000 people die annually from lung cancer, malignant mesothelioma, and asbestosis
due to occupational asbestos exposure. Malignant mesothelioma and lung cancer are
caused by all major types of asbestos. Asbestos causes more lung cancer deaths than
malignant mesothelioma of the pleura; most cases of the latter are due to asbestos
exposure. The cancer risk increases with cumulative asbestos exposure, with increased
risk even at low levels of exposure to asbestos. Based on empirical studies, an estimated
cumulative occupational exposure to asbestos of 1 fiber/mL-year substantially raises
malignant mesothelioma risk. No safe threshold for asbestos exposure has been established
for lung cancer and mesothelioma. The validity of fiber-type risk assessments depends
critically on the quality of exposure assessments, which vary considerably, leading
to a high degree of uncertainty. Asbestos exposure without asbestosis and smoking
increases the risk of lung cancer. The joint effect of asbestos and smoking is supra-additive,
which may depend in part on the presence of asbestosis. Asbestos workers who cease
smoking experience a dramatic drop in lung cancer risk, which approaches that of nonsmokers
after 30 years. Studies to date show that longer, thinner fibers have a stronger association
with lung cancer than shorter, less thin fibers, but the latter nonetheless also show
an association with lung cancer and mesothelioma. Low-dose chest computed tomographic
scanning offers an unprecedented opportunity to detect early-stage lung cancers in
asbestos-exposed workers.
Keywords
asbestos - lung cancer - malignant mesothelioma - asbestosis - chrysotile
