An explosion in the number of cancers

The use of asbestos fibers is now prohibited in the United States. Yet they could continue to wreak havoc for a long time. 30 000 new cases of cancers are due each year to this product in developed countries. And many other parts of the world are in danger of being hit in their turn.

One in seven people exposed

Asbestos kills slowly. This explains why today's specialists are so worried by the devastation that these mineral fibers, which have long been used in industry and the building industry, could cause for several decades to come. Gradually, an increasing number of developed countries have decided to put an end to the manufacture of asbestos. Progressively, pulmonary fibrosis (asbestosis) caused by the inhalation of asbestos fibers is becoming rare in the industrialized countries. At the same time, the number of asbestos-related cancers is exploding because the number of people in contact with this pollutant was particularly high in the 1970s. This is partly due to the asbestos experts' During a symposium on the pulmonary consequences of asbestos during the 11th Annual Congress of the European Society of Respirology (ERS) in 2001.

A threat that spreads over the planet

We know that asbestos promotes the appearance of two major types of cancers

Preventing asbestos-related cancers is not easy

According to Antti Tossavainen of the Finnish Institute of Occupational Medicine in Helsinki, the latest estimates suggest that 30,000 new cases of cancer, including 10,000 mesotheliomas and 20,000 lung cancers, are caused each year by Asbestos in Western Europe, North America, Japan and Australia. And because of their long lead time, asbestos-related cancers will increase steadily until 2020-2030.

Presented at this European congress of pneumology, work further amplifies the reasons for concern. Indeed, a study undertaken by Krassimir Mitchev at the Erasmus Hospital in Brussels suggests that one in seven adults would have pulmonary signs of exposure to asbestos.

To support this figure, the results of 160 autopsies carried out consecutively on 100 men and 60 women between 1998 and 2000. To the surprise of this Belgian team, pleural plaques which translate a thickening of the pleura were found in 14% Of these people, who were 68 years old on average, as well as in 20% of men. In 13% of autopsied individuals, the asbestos concentration reached a threshold indicating significant contamination. (1,000 "abestosic" bodies per gram of dry pulmonary tissue).

These alarming data are likely to apply in countries other than Belgium. Far from being confined to the developed countries, the question of asbestos is indeed planetary because its manufacture remains important in many regions of the globe. For example, it continues to exceed 700 000 tonnes per year in Russia, the world's largest producer, reaching 450 000 tonnes in China and 335 000 tonnes in Canada. According to Antti Tossavainen, more than 2 million tonnes of asbestos were still produced worldwide in the year 2000.

How to limit the harmful consequences of asbestos? Of course, by strengthening the prohibition and protection measures but also by improving the screening of exposed persons. However, if these means have proved their usefulness in the case of asbestosis-induced asbestosis fibroses, they are more difficult to implement in the case of cancers.

Mesothelioma, a particularly serious cancer, seems unfortunately less sensitive to the means of prevention.

On the other hand, it might be considered to strengthen the diagnosis of lung cancer in its early stages when it is still curable. A study in Bethesda, in the United States, suggests that a pulmonary scan at the scanner once a year, or even twice a year, would detect lung cancers that are not well evolved in exposed subjects. A European Commission should be set up to better define the persons to benefit from these early detection techniques.

If the use of asbestos has been banned in the United States since 1997, hundreds of thousands of professionals - the building in particular - were exposed before that date.

In the first place, bronchial cancer is sometimes difficult to connect with this agent because of the high frequency of smoking, followed by cancer of the pleura (mesothelioma), the envelope that surrounds the lungs.