PURPOSE: Relationship between exposure to coal mine dust and lung cancer remains controversial but, in a previous study (abstract, Chest 2004), we had found no difference in the occurrence of lung cancer (LC) between a large series of coal miners and the overall Belgian population. In the opposite, the literature generally considers crystalline silica (CS) as a human carcinogen. We tried to verify this by reviewing the rate of LC among Belgian workers compensated for silicosis, excepted coal workers pneumoconiosis.
METHODS: We reviewed retrospectively the files of all workers recorded for non-coal workers silicosis by the Belgian Fund for Occupational Diseases, dead between 1992 and 2002. Occupational exposure was various: foundry, quarries, ceramics, pottery, firebricks, and metal blast furnace. 405 well-documented files were available (388 males / 17 females). The mean age at death was 74 years. 68% were smokers or ex-smokers. The mean duration of exposure was 22.3 years and the end of exposure was meanly 1975.
RESULTS: 58 (14.2 %) of them had developed a lung cancer. This rate is significantly higher than in the overall male Belgian population, aged 60 years or more (10.9 %). 93 % of them were smokers or former smokers, and all were men. No difference was found in the group with LC concerning the duration of exposure, but LC was mainly diagnosed in foundry and metal blast furnace workers.
CONCLUSION: Silica exposure other than coal mine dust seems to be an independent factor of risk to develop a LC, even if some confounding agents like smoking and exposure to other carcinogens may be implicated. In this study, the relative risk for LC was 1.3.
CLINICAL IMPLICATIONS: It is suggested that special medical supervision could be proposed to these workers. Compensation of LC as occupational disease in workers exposed to CS should also be discussed.
DISCLOSURE: Dominique Lauwers, None.