Does asbestosis increase the risk of lung cancer?

The question of whether asbestos workers with or without asbestosis have the same risk of lung cancer has not been adequately addressed in the literature. Studies of asbestos workers indicate that clinical symptoms and abnormal lung X-rays are more frequent among smokers than non-smokers, and some studies show that workers with asbestosis compared to those without asbestosis are more likely to be smokers or ex-smokers. Since smoking has a large affect on the risks of lung cancer, smoking habits should be considered when evaluating the risk of lung cancer among persons with and without asbestosis. Some studies show that the risk of lung cancer is higher for persons with asbestosis compared to persons without asbestosis, but none of these studies also considered the combined effects of smoking and asbestos exposure on the risk of lung cancer. It is unlikely that the higher risk of lung cancer to persons with asbestosis is only due to their higher prevalence of smoking. Some studies have suggested that asbestos workers with asbestosis may have a higher risk of lung cancer, but no definite conclusions can be drawn since dose-response relations were not evaluated. Further studies are needed to evaluate the interrelationships of smoking, asbestosis and the risk of lung cancer.