Asbestos is one of a large number of agents that can cause lung cancer, the most important of which is tobacco smoking.
Lung cancer usually has no specific clinical signs suggesting a particular cause and asbestos exposure and smoking act together to increase the risk. This – together with the fact that cases usually take many years to develop – makes it difficult to be sure about the cause of individual cases. As a consequence, data sources that rely on the counting of individual cases attributed to asbestos exposures, such as Industrial Injuries Disablement Benefit (IIDB) and the Health and Occupation Reporting (THOR) schemes, tend to underestimate the true scale of asbestos-related cases.
Epidemiological analyses that are representative of the British population suggest that there are likely to be about as many lung cancer cases attributed to past asbestos exposure each year in the population as a whole as there are mesotheliomas 1, 2. This implies there are currently in excess of 2000 asbestos-related lung cancer deaths each year.
This estimate is uncertain. Since asbestos and smoking act together to increase the risk of lung cancer, it is affected by past smoking habits as well as the extent of asbestos exposure. The ratio of lung cancers to mesotheliomas is expected to fall over time, a reflection of reductions in both asbestos exposure and the prevalence of smoking. Among more specific groups of workers heavily exposed to asbestos in the past there were typically a greater number of excess lung cancer cases than there were mesotheliomas3.
Lung cancer is still typically fatal within a few years of diagnosis and so, as with the mesothelioma, the number of annual deaths is similar to the annual incidence of new cases.
In recent years there have been, on average, around 300 new cases of asbestos-related lung cancer each year within the IIDB scheme and less than 100 cases identified by chest physicians each year within the THOR scheme.
Estimates of the burden of lung cancer attributable to occupational exposures other than asbestos are available based on the Burden of Occupational Cancer research.