Asbestos-related pleural plaques and lung cancer.

The English-language literature was reviewed to evaluate a possible relationship between asbestos-related pleural plaques and lung cancer in the absence of parenchymal asbestosis. There were six cohort studies in which the comparison group was limited to unexposed persons or the general population, four lung cancer case-control studies, and three autopsy studies. Of the 13 investigations, only 3 supported the hypothesis that lung cancer risk is elevated among persons with pleural plaques over the risk in unexposed people: 2 cohort studies from the same city in England with much the same data and 1 case-control study. These three studies had the most defects in design. The other ten studies failed to confirm the hypothesis. Thus, the weight of the evidence favors the conclusion that persons with asbestos-related pleural plaques do not have an increased risk of lung cancer in the absence of parenchymal asbestosis.