[Medical impact of screening of benign pleural lesions associated with the inhalation of asbestos dust].

Asbestos-related benign pleural lesions can involve the parietal pleura (pleural plaques), and/or visceral pleura as focal or diffuse (diffuse pleural thickening) fibrosis. Benign asbestos pleurisy and rounded atelectasis are linked with visceral pachypleuritis, the former as a cause, the latter as a consequence. The prevalence of these lesions, particularly pleural plaques, is very high, reaching 25% in populations of workers exposed intermittently to asbestos. Conventional radiology has a sensitivity less than 50% for detection of plaques, and a specificity less than 85%. Tomodensitometry is today the reference diagnostic tool: availability, cost and irradiation have to be considered before its use in mass screening. Pleural plaques are most often asymptomatic and a functional impairment cannot be proven usually on an individual basis. Visceral pleural thickening is more often accompanied by symptoms (dyspnea, pain) and functional impairment. There is no treatment susceptible to produce a regression of pleural lesions. Asbestos exposure increases the risk of pulmonary and pleural cancers. However there is no evidence of an increased risk in subjects with plaques compared with subjects without plaques but an equivalent asbestos exposure. The cost and the risk of diagnostic procedures induced by the screening, as well as the anxiety provoked by the detection of radiologic abnormalities are to be considered. Finally it is difficult today to justify the screening of benign pleural lesions by arguing an improvement of the life expectancy or of the quality of life of former asbestos exposed workers. It is probable that benefit of a screening will be of a social type, at an individual or a collective level.