definition of the Asbestos's
Asbestos's was defined by the Advisory Committee on Asbestos as "fibrosis of the lungs caused by asbestos dusts which may or may \ not be associated with fibrosis of the parietal (outer) or pulmonary (inner) layer of the pleura
clinical manifestation of the asbestos lung cancer
The symptoms attributable to it (shortness of breath and cough) can be produced in many other ways, and the diagnosis during life is made on the physical signs, the results of pulmonary function tests, and the radiographic findings, accompanied by a history of substantial exposure. The fibrosis of the lungs that is associated with asbestos is is, however, indistinguishable radiologically from cryogenic fibrosis alveolars (an uncommon disease of unknown cause*)
MEDICAL EFFECTS OF EXPOSURE
Knowledge of the medical effects of asbestos has accumulated slowly since the turn of the century
and it is now universally agreed that the exposure of men and women to asbestos fibres can, in certain circumstances, lead to three diseases: asbestosis, lung cancer, and mesothelioma of the pleura or peritoneum. It can certainly also cause a group of benign conditions of the pleura of variable importance, and it may cause a group of other cancers, including cancers of the larynx, gastrointestinal tract, and kidney, and conceivably a wide range of others. Some of the features of these conditions are, we believe, beyond dispute and we describe them briefly here, without giving detailed evidence in support
Lung cancer
The lung cancers that are caused by asbestos should properly be called bronchial carcinomas, as should the vast majority of lung cancers that are caused by other known agents.
Mesothelioma
Mesotheliomas of the pleura or peritoneum are normally so rare, other than after occupational or other unusual exposure to asbestos, that any case that occurs after well attested and substantial asbestos exposure is commonly accepted as due to that exposure, subject only to the qualification that the time since the exposure occurred must be long enough to permit the disease to have been produced.
The relationship of mesothelioma to asbestos differs in several ways from the relationship for lung cancer. The hazard appears to be more strongly dependent on the type of asbestos and to be largely or wholly unaffected by smoking. As a result of these and other differences, the ratio of the numbers of mesotheliomas and lung cancers produced by any given exposure to asbestos varies at least 10- fold from about 1-1 0 to 1-1
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