Keeping up with advances in mesothelioma research can be a difficult task. It seems like every day there is a new clinical trial being conducted or some new area being researched, and for good reason. Over 250,000 people have died as a result of asbestos exposure, and that number continues to climb. With continued effort and support, we can defeat this deadly disease.
One interesting study that looked into the relationship between asbestos related deaths and insulation workers is called, Asbestos-associated deaths among insulation workers in the United States and Canada, 1967-1987 by Selikoff, IJ Seidman, H Annals of the New York Academy of Sciences [ANN. N.Y. ACAD. SCI.]. Vol. 643, pp. 1-13. 1991. Here is an excerpt: In addition to showing an increase in deaths from asbestosis, a study of the causes of death in the 17,800 asbestos insulation workers followed prospectively for 20 years (1967-1986) has also showed significant increases in cancer in a variety of organs. These include lung cancer, pleural and peritoneal mesothelioma, gastrointestinal and other forms of cancer such as that of the oropharynx and buccal cavity, larynx, kidney, pancreas, gallbladder, and bile ducts. On the other hand, no increase were found for cancer of the urinary bladder, prostate, testis, primary cancer of the liver, and primary cancer of the brain, nor for melanoma, leukemia, or lymphoma. Since the study provided extensive data, reflecting 301,592.6 person-years of experience, one can be fairly confident that, at least for this asbestos exposure, at this time, the "negative" finding can be accepted with some assurance. Apparently each organ and tissue has its own neoplastic response to asbestos; in some tissues cancer risk is increased, but not in others.
Another study worth looking at is called, Asbestos-related disease in the workplace and the environment: controversial issues. By Churg A. - Department of Laboratory Medicine, University Hospital, University of British Columbia, Vancouver, Canada. Monogr Pathol. 1993;(36):54-77. Here is an excerpt: The classical pathologic diagnostic criteria for asbestosis, namely the presence of diffuse interstitial fibrosis resembling usual interstitial pneumonia, and asbestos bodies visible in ordinary tissue sections, have proved to withstand the test of time. Cases without asbestos bodies visible in routine or iron-stained tissue sections almost never turn out to be asbestosis. It should be remembered that workers with asbestos exposure develop all of the interstitial lung diseases to which the remainder of the populace is subject; some of these conditions are treatable and should not be misdiagnosed as asbestosis, which is not treatable. There is strong epidemiologic and pathologic evidence that the only association of asbestos exposure and lung cancer is the association of asbestosis and lung cancer. Thus, a lung cancer should only be attributed to asbestos exposure when asbestosis is present on clinical or pathologic grounds. The histologic type and location of the tumor are irrelevant in this regard. Analytical electron microscopy indicates that chrysotile asbestos does induce mesothelioma in man, but that extremely high levels of retained fibers, levels as high as those seen in cases of asbestosis, are required for this event to occur. The weight of the evidence suggests that exposure of the general population to the very low levels of chrysotile that are found in some public building (levels not greatly different from ambient air) will never produce mesothelioma, asbestosis, or lung cancer because these diseases all appear to require quite high-level occupational chrysotile exposure. Even if one accepts the ideas (probably wrong) that any level of asbestos exposure carries a risk of cancer, and that mathematical extrapolation of risk from high-level occupational exposure to low-level building exposure is scientifically valid, the calculated risks are much smaller than real everyday risks such as driving to work. Thus, exposure to asbestos at environmental levels appears to produce no real dangers to health.
For more information, please read these studies in their entirety and consider doing some independent research on your own.
No comments:
Post a Comment