Lung cancer and asbestos exposure: asbestosis is not necessary.

Recent commentaries on the issue of asbestos-related lung cancer have raised important points. One major question is whether lung cancer can be attributed to asbestos exposure in the absence of asbestosis. This review attempts to place the debate in the proper context for establishing causation. Relevant epidemiologic and pathologic studies are analyzed, as well as the scientific basis for each position in the debate. The assertion that asbestosis must be present in order to attribute a lung cancer to asbestos exposure does not meet accepted standards for establishing causation. In addition, some evidence has been incorrectly cited in support of this position. This discussion can benefit from clearer definitions of asbestosis, a more thorough evaluation of the available scientific information, and a proper context for determining causation. This review of the available evidence indicates that lung cancers can occur as a result of asbestos exposure, in the absence of clinical or histologic asbestosis. Causation in an individual should be assessed by considering duration of exposure, intensity of exposure, and appropriate latency.