Affections pleuropulmonaires bénignes liées à l’amiante

[Compensation of occupational diseases during monitoring of the ARDCO cohort]

INTRODUCTION

Questions concerning under-reporting of occupational diseases (OD) linked to asbestos exposure are regularly voiced in France. Monitoring of the French multicenter Asbestos-Related Disease Cohort (ARDCO), which ensures post-occupational medical surveillance of subjects having been exposed to asbestos, provides information on (1) the medico-legal steps taken following screening by computed tomography (CT) for benign thoracic diseases, and (2) recognition of OD as a causal factor in malignant diseases.

METHODS

OD recognition - and possible compensation - was analyzed in July 2021 among 13,289 volunteers in the cohort recruited between 2003 and 2005.

RESULTS

Fifteen percent of the subjects in the cohort were found to have at least one recognized asbestos-related OD (78.2% benign pleural disease, 10.3% asbestosis, 14.2% lung cancer, and 6.0% mesothelioma). Only 58% of pleural plaques reported by the radiologist who performed the CT resulted in their recognition as ODs. On a parallel track, 88.7% of the mesotheliomas identified based on French National health insurance data and 46.9% of lung cancers were recognized as ODs.

CONCLUSIONS

This study confirms the feasibility of a system designed to facilitate recognition, leading to possible compensation, of asbestos-related occupational diseases. The system could be improved by better training of the medical actors involved.

[Exposure to asbestos and the indoor environment]

A link between the inhalation of asbestos fibres and the outcome of benign and malignant respiratory diseases has been established from numerous epidemiological data in occupational settings. Occupational exposure limit values have been established with a gradual lowering of these over time. Conversely, there are few epidemiological data dealing with exposure in the indoor environment. However, numerous materials and products containing asbestos (MPCA) are present in the indoor environment, due to their widespread use in the construction sector in the years between 1960 and 1990. The regulations were changed from the late 1990s, leading to a systematic inventory of the presence of asbestos-containing materials in buildings. The aim of this manuscript is to clarify the different types of MPCA encountered in the indoor environment, to describe the techniques used to highlight asbestos depending on the nature of the materials, the regulatory requirements relating to asbestos in non-occupational situations, and to update on the state of knowledge on asbestos-related diseases in the indoor environment.

[What are the tools for post-occupational follow-up, how should they be performed and what are their performance, limits and benefit/risk ratio? Chest X-Ray and CT scan]

Chest radiography and computed tomography (CT) are the two radiological techniques used for the follow-up of people exposed to asbestos. Since the last conference of consensus (1999), the scientific literature has primarily covered high-resolution CT and high-resolution volume CT (HR-VCT). We consider in turn the contribution of digital thoracic radiography, recommendations for the performance of HR-VCT to ensure the quality of examination while controlling the delivered radiation dose, and the need to refer to the "CT atlas of benign diseases related to asbestos exposure", published by a group of French experts in 2007, for interpretation. The results of the published studies concerning radiography or CT are then reviewed. We note the great interobserver variability in the recognition of pleural plaques and asbestosis, indicating the need for adequate training of radiologists, and the importance of defining standardized, quantified criteria for CT abnormalities. The very low agreement between thoracic and general radiologists must be taken into account. The reading of CT scans in cases of occupational exposure to asbestos should be entrusted to thoracic radiologists or to general radiologists having validated specific training. A double interpretation of CT could be considered in medicosocial requests. CT is more sensitive than chest radiography in the detection of bronchial carcinoma but generates a great number of false positive results (96 to 99%). No scientific data are available to assess the role of imaging by either CT or chest radiography in the early detection of mesothelioma.