Mesothelioma Information - Mesothelioma Symptoms, Fibrosis
Asbestos, mesothelioma and lung cancer
While pulmonary fibrosis due to exposure to asbestos (asbestosis) has been known for decades, the first reports of individual cases of asbestosis combined with pulmonary cancer which appeared from time to time in various countries were accepted more as a curiosity. They did not attract much attention until in 1947 a British Chief Inspector of Factories, E. R. A. Merewether, reported that lung cancer was found to be the cause of death in 13.2% of persons known to have asbestosis who had died and been autopsied between 1923 and 1946. A similar high proportion of cancer deaths in asbestosis was found by other pathologists and the probability of a role of asbestos in pulmonary carcinogenesis was definitely established by an epidemiological study by Doll in 1955, and confirmed by further studies.
Soon afterwards a new surprising discovery was made in South Africa. An accumulation of cases of an otherwise very rare tumour of the pleura and peritoneum, the malignant mesothelioma, was reported by Wagner in 1959 and related to exposure to the locally mined type of asbestos, crocidolite. Soon afterwards cases were identified in non-mining occupational exposures to asbestos in England, in the United States and elsewhere. In contrast with asbestosis, and in contrast with asbestos-related pulmonary cancer, mesothelioma was found also in persons whose exposure was not necessarily occupational.
Bronchogenic carcinoma related to asbestos
Bronchogenic carcinoma of the lung. This is a disease very common in the general population. While in many countries the total mortality from cancer slowly declines, the incidence and mortality from lung cancer increases and stands as the most frequent cause of death from cancer, particularly in cigarette smokers. It begins with transformation of the mucous membrane lining the inside of the bronchus at various levels and such foci of transformation may remain at their initial spot for some time shedding at times atypical or metaplastic cells into the sputum without causing other symptoms. This is the period in which we sometimes may succeed in discovering these pre-cancerous, or the earliest cancerous, changes by sputum cytology sooner than by other diagnostic methods. Some of such early alterations of cells is reversible and may spontaneously heal when the cause disappears, e.g. when the person stops smoking. When the original focus develops definite cancer cells, the focus begins to grow, to bleed and slowly to obstruct the airway, a growing malignant tumour becomes visible on the radiogram, and unless it can be surgically removed as soon as confirmed, it tends to spread through growth and through dissemination by blood and by lymph and to lead eventually to death. Supporting treatment by chemotherapy and radiation successfully prolongs life and radical surgery can provide complete healing.
The various components of the bronchial lining may undergo malignant transformation and consequently the carcinoma may be composed of various cells and have various histological appearances such as adenocarcinoma or squamous, or oat-cell carcinoma.
There are no histological or other characteristics which would specify the individual lung cancer as cancer caused by asbestos.
In many cases of asbestos-linked pulmonary cancers the lungs also show pulmonary fibrosis-asbestosis microscopically, and often macroscopically, and on X-ray examination. Some scientists believe that so-called "asbestos lung cancer" can only develop on a pathologically changed terrain of asbestotic fibrosis. There is evidence of such a possibility in human pathology: the scar-carcinoma. Others believe that exposure to asbestos alone, particularly in a smoker, may provoke cancerous growth without also causing asbestosis. The decision between the two opinions is difficult to reach because in individual clinical cases of bronchogenic carcinoma we cannot distinguish what is an "asbestos cancer", a "cigarette cancer", or lung cancer from yet another cause. Thus, in most countries bronchogenic carcinoma is considered an occupational disease due to asbestos, e.g. for workmen's compensation, only in the presence of coexisting asbestosis. If pulmonary fibrosis were a prerequisite for development of asbestos-linked lung cancer, it would follow that lowering exposures to asbestos to levels which effectively prevent asbestosis would automatically eliminate "asbestos lung cancer".
Mesothelioma Information
Malignant mesothelioma asbestos is a rare type of cancer that affects the mesothelial tissue lining of three large bode cavities. There are three distinct types of mesothelioma cancer: pleural mesothelioma (the most common type), peritoneal mesothelioma and pericardial mesothelioma.
Mesothelioma treatment options include surgery, chemotherapy, radiation therapy, photodynamic therapy, immunotherapy and gene therapy; however, none have been able to thwart the deadly cancer. Mesothelioma symptoms vary dependent on the type of the disease one is suffering from, though the most common presenting symptom is chronic chest pain that is associated with a buildup of fluid inside the pleural space.
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