Whether asbestos exposure per se can increase the risk of lung cancer or if asbestosis is a necessary prerequisite for this disease has been and is still hotly debated in the literature (1-2). Pleural plaques is a fairly common radiological finding among men in the general population and (provided that the plaques are properly defined radiologically) is a good indicator of former usually occupational exposure. In 1997, it was shown that in a material of more than 1500 persons with pleural plaques but without radiological or functional signs of asbestosis, mortality in lung cancer was significantly increased (3). This cohort has now been followed further to see whether the lung cancer risk remains high.
The identity of all patients with lung cancer from 1992 to 2003 from the Swedish Cancer Registry was matched with the plaque cohort. The study was approved by the Ethical Committe.
Between 1970 and 1985, 1596 men were include in the material, the vast majority from findings of a health survey. They were born between 1887 and 1948. At the end of 1991, 1126 were still alive. From 1992 to 2003, 10 lung cancers occurred in this small cohort. This is more than expected.
The risk of lung cancer in the Plaque cohort is moderately increased, strengthening the hypothesis that asbestos and not asbestosis is a contributing cause of lung cancer.
Pleural plaques should alert the clinician that the person in question has been exposed to asbestos and therefore has a moderately increased risk for bronchial carcinoma.References: 1 Hillerdal G, Henderson DW. Scand J Work Environ Health 1997;23:93-103.2. Weiss W. Chest 1999;115:536-49.3. Hillerdal G. Chest 1994; 105:144-50.
Gunnar Hillerdal, None.