The most common form of mesothelioma is malignant pleural mesothelioma, a so-called primary form of pleural cancer. 80 to 85% of mesotheliomas are due to exposure to asbestos which may have occurred several decades before the development of the disease. Exposure to asbestos is mainly of occupational origin, but it can also be environmental (presence of asbestos in certain soils and their surroundings, in particular in rocks of Haute-Corse). The only recognized risk factor is asbestos. It is classified as 1 (a certain carcinogen) by the IARC. Certain artificial mineral fibers, exposure to ionizing radiation, to the SV40 virus or to chemical agents such as bromates, nitrosoureas, or nitrosamines, are risk factors for suspected mesothelioma. The occupational disease tables No. 30 (general scheme) and 47 (agricultural scheme) provide compensation for patients who have been exposed to asbestos during their professional activity. In the event of recognition as an occupational disease, the worker has the right to stop their activity early from the age of 50, and compensation by the FIVA. Improving the observation and monitoring of cancers linked to the professional environment is one of the measures of the 2009-2013 cancer plan. By decree n ° 2012-47 of 16 January 2012, mesotheliomas are added to the list notification of reportable diseases.
General information on mesothelioma
Mesothelioma is a rare malignant tumor that affects the cells of the mesothelium, the protective membrane that covers most of the internal organs of the body, including the pleura, peritoneum, and pericardium. Its most common form is malignant pleural mesothelioma. It is a so-called primary form of cancer of the pleura, which is characterized by a multiplication of cancer cells in the tissue constituting the pleura. The pleura is a membrane that envelops the lungs, made up of two layers, one covering the lungs (inner layer or visceral pleura), the other covering the inside of the thoracic cavity (outer layer or parietal pleura). When the disease occurs, the pleura thickens takes on a scalloped appearance, and the space between these two layers (pleural cavity) can fill with liquid and cause breathing difficulties. There were an estimated 906 new cases of pleural cancer in 2005 in France, 71% of which occurred in humans. Six out of 10 new cases are diagnosed in people over the age of 69. The most recent data show 1090 deaths per year.
Asbestos as the main cause
80% to 85% of mesotheliomas are linked to exposure to asbestos, mainly of occupational origin, but also environmental. This exposure could have occurred several decades before the development of the disease. Multiple parameters influence the onset of mesothelioma:
The time elapsed since the start of the exhibition.
The cumulative dose of asbestos: it is expressed in fibers per milliliter (mL) of air multiplied by the number of years of exposure for occupational exposures, and in fibers per liter of air multiplied by the number of years of exposure for exposures of the general population;
Peaks of exposure; the size and geometry of the fibers that determine the penetration of asbestos into the respiratory tract and their biopersistence : the most harmful fibers correspond to a length greater than 5 micrometers (μm) and to a diameter less than 0.5 μm
Asbestos is the only recognized risk factor for pleural mesothelioma (classified group 1, carcinogenic by the IARC ); apart from erionite, a natural mineral fiber from the zeolite family, which is also a recognized risk factor, which is only present in certain regions of Turkey. The occurrence of mesothelioma, in the absence of exposure to asbestos, is also possible (it affects about one in a million people).
Other risk factors discussed
Other potential factors are mentioned and need to be confirmed: certain artificial mineral fibers such as refractory ceramics, exposure to ionizing radiation, to the SV 40 virus or to chemical agents such as bromates, nitrosoureas, nitrosamines. The role of individual factors of genetic susceptibility is likely, but no gene predisposing to mesothelioma has been identified. Contrary to the case of lung cancer, exposure to tobacco has not been demonstrated in the risk of developing mesothelioma.
Compensation as an occupational disease
In case of suspicion of exposure to asbestos during professional activity, it is recommended to initiate a recognition process for occupational disease. The occupational disease tables No. 30 of the general scheme and No. 47 of the agricultural scheme provide for compensation for the victims. Proof of exposure is not necessary, as the diagnosis of mesothelioma is authoritative. In the event of recognition as an occupational disease, the worker has the right to cease their activity early from the age of 50, and compensation by the FIVA which aims to repair the damage suffered by the worker or his assigns. This FIVA compensation is also granted to the self-employed, environmental victims and beneficiaries.
Strengthened public health policies
Mesotheliomas are the subject of a national surveillance program in 22 departments and the exhaustive registration of all incident mesotheliomas completes a specific national register called the national multicentric register of pleural mesothelioma (Mesonat). The 2005 – 2009 occupational health plan (and 2010 – 2014 under development), the second national health and environment plan and the 2009 – 2013 Cancer plan include all policies and measures to prevent risks related to the general environment and work. Thus, improving the observation and monitoring of cancers linked to the professional environment is one of the measures of the 2009 – 2013 cancer plan, notably with a measure aimed at making the declaration of mesotheliomas compulsory.
By decree n ° 2012-47 dated 16 January 2012, mesotheliomas are added to the official list of diseases with compulsory notification. This compulsory declaration is implemented by the French Institute for Public Health Surveillance (InVS) at the request of the Ministry of Health. Any new case of mesothelioma, whatever its anatomical site (pleura, peritoneum, pericardium …), must now be notified to the doctor of the Regional Health Agency (ARS), by any doctor (pathologist or clinician) practicing in mainland France or ultramarine and who diagnoses it. Note also that within the framework of the Cancer and Environment Unit of the Léon Bérard Center (Center for the fight against cancer in Lyon and Rhône-Alpes), a “professional cancer” consultation was set up, in collaboration with the Professional Pathology Consultation Center of the Hospices Civils de Lyon, so that patients at the Léon Bérard Center can benefit from a systematic approach to researching occupational exposures for compensable cancers in occupational disease, and particularly with patients suffering from cancer lung and mesothelioma.