[Follow-up of subjects occupationally exposed to asbestos, what are the objectives, the benefits, and the possible risks?].
Résumé
The follow-up of workers occupationally exposed to asbestos has two possible beneficial effects: (1) individually, both medical by screening for diseases related to asbestos and social by notification of occupational disease and/or compensation from the indemnity funds for asbestos victims; (2) collectively, by the establishment of epidemiological surveillance (follow-up of cohorts) and evaluation of the impact of follow-up in terms of health benefits and compensation. The respiratory disorders related to asbestos are: cancer (malignant pleural mesothelioma and bronchial carcinoma), asbestos-related pulmonary fibrosis, and pleural disease (plaques, pleural fibrosis and benign pleurisy). In the light of the data currently available and the effectiveness of the tools used, medical and public health benefits of screening for mesothelioma have not been demonstrated. The early diagnosis of primary bronchial carcinoma can theoretically improve the prognosis of the subjects screened, particularly by identification of stage I disease on CT (pulmonary nodules). This is a common finding but there are a large number of false-positives. While we await the results of several international randomised trials, the benefits of a screening programme for bronchial carcinoma in the population at risk have not been demonstrated. There is no effective treatment for asbestosis but this is an independent risk factor for bronchial carcinoma and it is evidence of heavy asbestos exposure. Stopping smoking in subjects suffering from asbestosis will reduce the incidence of bronchial carcinoma. There is no effective treatment for asbestos-related benign pleural diseases but these are markers of exposure. The presence of pleural plaques has not been shown to be an aetiological factor for thoracic cancers. Post-occupational follow-up may involve risks to health, particularly repeated irradiation and invasive diagnostic procedures. It is also necessary to consider the psychological consequences inherent in all screening programmes. In conclusion, post-occupational follow-up might reduce the mortality of lung cancer by screening for localised disease and its incidence by a targeted anti-smoking programme. The theoretical benefits, that have not yet been demonstrated, have to be seen in perspective with the risks to physical and psychological health related to both screening and diagnostic procedures.