Screening for occupational diseases related to asbestos in France: which medical examination should be preferred?

 Asbestos was introduced massively in indutrialized countries at the end of World War I. The use of asbestos wasn't controlled in France until 1977, when standards of exposure to fibres were introduced. Asbestos has been classified as carcinogen since 1976 and banned in France since 1997.
The professions concerned by exposure to asbestos have evolved over the decades. Whereas occupational diseases use to strike professionals of the production in the sixties, painters and jewelers are now the first concerned. The building sector has still been the most exposed in the last years.

The current form of screening for employees and craftsmen

For employees or former employees of the "régime général" [general scheme] which are not in activity:

These people - inactive, seeking employment, retired -, who have been exposed to asbestos in the past, benefit from a postoccupational supervision. The supervision protocol was defined by the "annexe II de l'arrêté du 28 février 1995 pris en application de l'article D 461-25 du code de la Sécurité sociale". It fixes the standard of attestation exposure and the examination modalities during the postoccupational supervision of the employees who were exposed to carcinogenic agents or processes.
The examinations to be carried out are a clinical examination, a chest X-ray and sometimes a pulmonary function tests - such as spirometry - every 2 years. These check-ups are entirely covered by  le Fonds d’action sanitaire et sociale de la Sécurité sociale (Funds of social and sanitary action of the Social Security) [1].

For an employee still in activity, who was exposed to asbestos in the past or currently:

These people are submitted to a clinical examination every year, to a chest X-ray and a spirometry every two years, in the context of a "surveillance médicale renforcée" (heigthened medical supervision) carried out by the occupational physician in accordance with the "arrêté du 13 décembre 1996 portant application des articles 13 et 32 du décret n° 96-98 du 7 février 1996 relatif à la protection des travailleurs contre les risques liés à l'inhalation des poussières d'amiante déterminant les recommandations et fixant les instructions techniques que doivent respecter les médecins du travail assurant la surveillance médicale des salariés concernés" [relating to the protection of workers against the risks associated with inhaling asbestos dust, determining the recommendations and the technical instructions that ought to be followed by the occupational physicians who are in charge of the medical supervision of the concerned employees]. Although the "décret 96-98" was repealed, these articles are still in motion until the order linked to article R 4412-138 of the French labor law fixing the technical instructions that the occupational physician has to follow in the context of asbestos  heigthened medical supervision is published.
According to article R 4624-20, the occupational physician can judge the frequency and nature of the examinations that are included in the "surveillance médicale renforcée" [heigthened medical supervision] and usually , the physician sets the same frequency for the complementary examinations and the clinical one, i.e. every year. The assumption of regulatory examinations for monitoring falls to the company which currently employs the concerned person. These examinations are assumed by the employer even if the employee is not exposed to asbestos in his company [2].

For the craftsmen :

One retired craftsman out of two of the "Régime social des indépendants" [RSI; social system for the self-employed] has been exposed to asbestos during at least 25 years.
All craftsmen of the RSI, who have been exposed to asbestos, are currently being identified in order to offer them an exposure assessment and a medical supervision [3].
Only recently retired craftsmen and specific regions are concerned for the moment – Aquitaine, Poitou-Charentes, Nord-Pas-de-Calais, Lower and Upper-Normandy, Picardy. The physician carries out a clinical examination and necessarily sends the craftsman who was exposed to asbestos to a radiologist who makes a multisection chest Spiral CT without injection ,– or even one section. The examinations are covered by the RSI [4].
In case of anomaly, the crafstman is sent to the "Fonds d’indemnisation pour les victimes de l’amiante" [FIVA; Fund of compensation for the victims of asbestos] for compensation.

Official recommendations

The "Société française de pneumologie de langue française" [SPLF; french-language Society of pneumology] issued its latest recommendations for the detection of asbestos diseases in 2006 [5].
Suprisingly, according to the SPLF, ''the medical and public health interest of screening is today still not prooved in view of the data currently available on the pleural mesothelioma - frequency, prognosis, therapeutic - and on the performance – sensitivity, specificity - of screening tools – chest imagins, biological markers –''. Therefore, regulation goes against the current scientifical data and the current provisions must be held as a precautionary principle.

The SPLF suggests a CT chest scan from the age of 50, under the postoccupational supervision of people previously exposed to asbestos. The thoracoabdominal tomography is known as being a key examination of diagnostic imaging of pleural mesothelioma. Indeed, it enables to spot pleural thickening, the impact of fissures which are suggestive signs of the disease.
For the detection of mesothelioma, front chest X-ray is not much sensitive to spot a pleural effusion clearly, even in conditions of standardized reading – LIO codification. It lacks sensitivity to diagnose discrete forms of pulmonary or pleural fibrosis. It only enables to diagnose severe forms.
In its recommendations of 1999, the SPLF laid stress on the radiation of the scanner that was likely to encourage the development of mesothelioma. But the Spiral CT now available, only delivers a very small amount of radiation compared to a conventional scanner.

What is done in North-America

In the U.S., the first intention is not based on doing the scanner. Only a lung X-ray (anterior oblique view) and a spirometry are carried out on this occasion. It is only then that a scanner can be done [6].
In Canada, numbers of studies were carried out and several screening methods were tested : chest X-rays, pulmonary function tests, gallium 27 absorption coupled with nuclear imaging, axial tomography and bronchoalveolar lavage. Here are the conclusions of these various studies : diseases linked to asbestos are often detected too late and axial tomography is more sensitive to detect the disease [7].

Occupational physician's responsibility involved

Currently, on a regulatory level, screening for diseases linked to asbestos includes a chest X-ray and a pulmonary function test for employees, whereas the assessment put in place by the RSI for recently retired craftsmen includes a Spiral CT exclusively. Screening among craftsmen therefore seems much more in tune with the current recommendations of the SPLF for the detection of mesothelioma, than the one among employees.
Some occupational physicians who ensure the monitoring of employees are getting concerned of this gap between scientific knowledge on the one hand and texts in motion on the other hand. While physicians are taken to court for their so-called passivity in cases related to asbestos, shouldn't a Spiral CT be part of the screening regulatory examinations for mesothelioma? Couldn't occupational physicians be blamed for not prescribing this examination whereas it is known as the most adapted screening examination ? A doctor involved is likely to be condemned for not having fulfilled his obligation of means [8].
But it is far from being simple. The Spiral CT is not covered by the employer because it is not part of the planned regulatory examinations. If the Spiral CT becomes a part of it, we can easily imagine the cost of such a decision compared to mere chest X-rays, given the number of employees who would regularly benefit from it. But should human lives be sacrified to economic principles?
It is a matter of public health which should be solved as soon as possible by the publication of the decree indicating the technical instructions that the occupational physician has to follow during the "surveillance médicale renforcée" [heigthened medical supervision] for asbestos.