[Analysis of pleural plaque found at lung cancer screening examination]

In the screening test of lung cancer, we found that there was a high prevalence of cases with pleural plaque recognized by chest X-ray film in inhabitants living in A town in Kumamoto Prefecture. We detected abnormal pleural plaque in 148 (41.5%) of 357 cases received lung cancer screening. These pleural plaques resulted in pleural thickening and calcification. Two or three mines of serpentine and an asbestos factory existed in this region from 1883 until 1970. Although twelve cases had a history of factory work, none had fibrous changes in the lung fields on chest X-ray films. It was considered that the pleural plaque probably resulted from exposure to low doses of asbestos in the atmosphere or contact with asbestos workers in their homes. The incidence of lung cancer in this region was not higher than that in other regions in Kumamoto Prefecture. There were no cases of malignant mesothelioma in our hospital during the past eleven years.