Background

The Finnish Institute of Occupational Health (FIOH) convened an Expert Committee in 2014 to update the 1997 and 2000 Helsinki criteria on asbestos, asbestosis, and cancer.

Methods

The Collegium Ramazzini reviewed the criteria for pathological diagnosis of the diseases caused by asbestos presented in the 2014 Helsinki Consensus Report and compared them with the widely used diagnostic criteria developed in 1982 by the College of American Pathologists and the National Institutes of Occupational Safety and Health (CAP-NIOSH).

Findings

The sections of the Helsinki Consensus Report dealing with pathological diagnosis are based on a biased and selective reading of the scientific literature. They are heavily influenced by the outdated and incorrect concept that analysis of lung tissue for asbestos bodies and asbestos fibers can provide accurate information on past exposure to asbestos. Five specific problems are :

1.Over-reliance on the detection of “asbestos bodies” as indicators of past exposure to asbestos.

2.Over-reliance on asbestos fiber counts in lung tissue as an indicator of past exposure to asbestos.

3.Use of the scanning electron microscope (SEM) at low magnification as a tool for evaluation of asbestos-related disease.

4.Failure to recognize that chrysotile is the predominant type of asbestos fiber found in pleural mesothelioma tissue.

5.Postulating the existence of a threshold for development of an asbestos-related lung cancer.

Conclusion

Accurate diagnosis of the diseases caused by asbestos must be based on a carefully obtained history of occupational exposure. An accurate exposure history is a far more sensitive and specific indicator of asbestos exposure than asbestos body counting or lung fiber burden analysis.

Ethical note

The sections of the 2014 Helsinki Consensus Report on asbestos, asbestosis, and cancer dealing with pathologic diagnosis of the diseases caused by asbestos appear to have been influenced by members of the Expert Committee with undisclosed financial conflicts of interest.