Pleura mesothelioma and exposure to asbestos

Summary The author reviewed literature data on the relationship between lead in blood levels (PbB) and various biochemical and haematological responses. PbB levels may be regarded as representative for internal dose. The percentage of subjects with a specified intensity of a specified response in groups of subjects has been calculated in relation to PbB. This Dose-Response (D-R) relationship portrays the increase of biological effects with increasing internal dose, qualitatively and quantitatively, and can be used to evaluate the health significance of Pb exposure in occupational and public health. D-R-curves have been calculated for -aminolaevulinic acid dehydratase activity in erythrocytes (ALAD), -aminolaevulinic acid excretion in urine (ALAU), protoporphyrin in erythrocytes (PPE), Na⁺-K⁺-ATPase activity in erythrocytes and reduced glutathion content of erythrocytes. Various other biochemical and haematological responses are discussed in regard to their relationship with PbB. In a subsequent paper the prevalence of functional effects in relation to PbB will be discussed.     

Pericardial mesothelioma and asbestos exposure

Pericardial mesothelioma (PM) accounts for 0.7% of all malignant mesotheliomas. Although asbestos exposure is a recognized etiological factor for pleural and peritoneal mesotheliomas, its role in the development of PM is controversial. The aim of this study is to describe the characteristics of PM cases occurred in Lombardy, a highly industrialized Region of Northern Italy. From the Lombardy Mesothelioma Registry we selected the incident cases of PM registered in the Lombardy Region between 2000 and 2009 and we abstracted clinical characteristics and history of asbestos exposure. We identified 8 cases (6 men and 2 women), with a median age at diagnosis of 55.5 years, representing 0.3% of all mesothelioma cases (n = 3059). The age-standardized incidence rate was 0.09 per million/year. Occupational exposure to asbestos was documented in 5 of the 7 cases for which we obtained an interview. Our findings support the role of asbestos in the pathogenesis of PM.     

Malignant mesothelioma from neighborhood exposure to anthophyllite asbestos

BACKGROUND: Anthophyllite asbestos has been reported to cause asbestosis, lung cancer, mesothelioma, and pleural plaques in occupationally exposed workers. Anthophyllite has also been associated with pleural plaques in Finland and Japan among those who live near mines and mills and have neighborhood or environmental exposure. METHODS: We evaluated a 38-year-old patient with pleural mesothelioma who lived, attended school, and delivered newspapers near a manufacturing facility that used exclusively anthophyllite asbestos fiber from ages 8-17 years. He had no work exposure to asbestos. RESULTS: The pleural mesothelioma was an epithelial type with tubulopapillary structures and was treated with an extrapleural pneumonectomy followed by radiation therapy. The malignant cells were positive by immunohistochemistry for cytokeratin but negative for carcinoembryonic antigen, S100, B72.3, and leu M1 antigen. Anthophyllite fibers were > 5 microm in length in lung tissue compared to 3 microm from a general population study. CONCLUSIONS: Anthophyllite asbestos has been associated with neighborhood environmental exposure and pleural plaques; we now report a neighborhood exposure and pleural mesothelioma.     

Primary malignant pericardial mesothelioma]

The case-history of a 41-year-old man is reported. He was admitted because of the sudden development of left hemiparesis, loss of consciousness and increasingly deeper coma. The ECG demonstrated second-degree AV block with Wenkebach conduction or episodes with complete AV block. The colour Doppler ultrasound and cranial CT examination revealed occlusion of the right internal carotid artery and a cerebral infarct of the right hemisphere. Within 24 hours patient died from herniation of the brainstem. Postmortem examination revealed a pericardial neoplasm infiltrating both left and right atrium, AV junctional area, interventricular septum and right ventricle. The tumor tissue grew transmurally and protruded into the cavities of the heart. The right internal carotid artery was occluded by a tumor embolism. The histochemical and immunohistochemical results proved that the tumor was a primary malignant pericardial mesothelioma. This kind of cardiac tumor involving the AV node and mimicking stroke is very rare.     

Risk of developing mesothelioma due to neighborhood exposure to asbestos]

Routes of asbestos exposure consist of occupational and non-occupational exposures, and furthermore the latter is classified as para-occupational, neighborhood or true general environmental exposure. Consequently, in order to evaluate health risk caused by neighborhood exposure to asbestos, it is necessary to exclude risk due to the other exposure routes from overall risk. We reviewed epidemiological studies on the relationship between neighborhood asbestos exposure and risk of mesothelioma. In studies on a crocidolite mine in South Africa and a chrysotile mine in Canada, occupational exposure was not excluded. In studies on a crocidolite mine in Australia and an asbestos manufacturing factory in U.S.A., risk caused by non-occupational exposure was evaluated, but the risk was not classified as para-occupational and neighborhood exposures. In a study on an asbestos cement factory in Italy, first, occupational and para-occupational exposures were excluded, and next, the incidence rate of mesothelioma in neighborhood residents was calculated, so that risk caused by neighborhood exposure could be evaluated. In case-control studies in Italy, South Africa, three European countries and the U.K., risks caused by occupational, para-occupational and neighborhood exposures were evaluated separately. As a whole, relative risk (RR) of neighborhood exposure in crocidolite and amosite mines was about 10 to 30 and RR in major asbestos factories was about 5 to 20. On the other hand, statistically significant RR of neighborhood exposure was not observed in chrysotile mines and some asbestos facilities.     

Modeling mesothelioma risk associated with environmental asbestos exposure

BACKGROUND: Environmental asbestos pollution can cause malignant mesothelioma, but few studies have involved dose-response analyses with detailed information on occupational, domestic, and environmental exposures. OBJECTIVES: In the present study, we examined the spatial variation of mesothelioma risk in an area with high levels of asbestos pollution from an industrial plant, adjusting for occupational and domestic exposures. METHODS: This population-based case-control study included 103 incident cases of mesothelioma and 272 controls in 1987-1993 in the area around Casale Monferrato, Italy, where an important asbestos cement plant had been active for decades. Information collected included lifelong occupational and residential histories. Mesothelioma risk was estimated through logistic regression and a mixed additive-multiplicative model in which an additive scale was assumed for the risk associated with both residential distance from the plant and occupational exposures. The adjusted excess risk gradient by residential distance was modeled as an exponential decay with a threshold. RESULTS: Residents at the location of the asbestos cement factory had a relative risk for mesothelioma of 10.5 [95% confidence interval (CI), 3.8-50.1), adjusted for occupational and domestic exposures. Risk decreased rapidly with increasing distance from the factory, but at 10-km the risk was still 60% of its value at the source. The relative risk for occupational exposure was 6.0 (95% CI, 2.9-13.0), but this increased to 27.5 (95% CI, 7.8-153.4) when adjusted for residential distance. CONCLUSIONS: This study provides strong evidence that asbestos pollution from an industrial source greatly increases mesothelioma risk. Furthermore, relative risks from occupational exposure were underestimated and were markedly increased when adjusted for residential distance.     

Histological types of malignant mesothelioma and asbestos exposure

The Los Angeles County Cancer Surveillance Program abstracts hospital pathology records on almost all cases of cancer occurring in the county. Those cases of pleural and peritoneal mesothelioma that occurred between 1972 and 1978 were identified. Occupational histories were obtained from interviews, and the histopathology of the tumours was reviewed by a member of a mesothelioma reference panel who was unaware of the exposure histories. The relation of asbestos exposure to the three histological types of mesothelioma (epithelial, mesenchymal, and mixed) was studied among the 29 cases for whom occupational histories were available and who were also considered to have histopathology consistent with mesothelioma. The proportion of cases exposed to asbestos was high for both the epithelial (11/17, 65%) and mixed histological types (6/11, 55%). The single case of mesothelioma classified as a mesenchymal type was also exposed to asbestos. Cases who had worked in shipyards were represented in each of the three groups. In cases who had worked in asbestos production and manufacture an exclusively epithelial type of tumour was observed. In cases who had worked as insulators or in heating trades the histological type was predominantly (3/4) mixed. These data do not support the hypothesis that any specific histological type of mesothelioma is especially related to asbestos exposure.     

Malignant mesothelioma: attributable risk of asbestos exposure.

OBJECTIVES--To evaluate a case-control study of malignant mesothelioma through patterns of exposure to asbestos based upon information from telephone interviews with next of kin. METHODS--Potential cases, identified from medical files and death certificates, included all people diagnosed with malignant mesothelioma and registered during 1975-1980 by the Los Angeles County Cancer Surveillance Program, the New York State Cancer Registry (excluding New York City), and 39 large Veterans Administration hospitals. Cases whose diagnosis was confirmed in a special pathology review as definite or probable mesothelioma (n = 208) were included in the analysis. Controls (n = 533) had died of other causes, excluding cancer, respiratory disease, suicide, or violence. Direct exposure to asbestos was determined from responses to three types of questions: specific queries as to any exposure to asbestos; occupational or non-vocational participation in any of nine specific activities thought to entail exposure to asbestos; and analysis of life-time work histories. Indirect exposures were assessed through residential histories and reported contact with family members exposed to asbestos. RESULTS--Among men with pleural mesothelioma the attributable risk (AR) for exposure to asbestos was 88% (95% confidence interval (95% CI) 76-95%). For men, the AR of peritoneal cancer was 58% (95% CI 20-89%). For women (both sites combined), the AR was 23% (95% CI 3-72%). The large differences in AR by sex are compatible with the explanations: a lower background incidence rate in women, lower exposure to asbestos, and greater misclassification among women. CONCLUSIONS--Most of the pleural and peritoneal mesotheliomas in the men studied were attributable to exposure to asbestos. The situation in women was less definitive.     

Malignant mesothelioma in Emilia-Romagna: incidence and asbestos exposure

This paper describes the activity, the sources of informations, methods and results of the "Emilia-Romagna Mesothelioma Registry" (ReM). The Registry started in 1996 and collects all cases of Malignant Mesothelioma (MM) occurring in Emilia-Romagna. 323 new cases (225 males and 98 females) have been detected during the period 1996-2001. Most cases (n = 286) concerned pleura. Other observed localizations were: peritoneum (n = 30), tunica vaginalis testis (n = 4) and pericardium (n = 3). Most of the cases were reported by the Institutes of Pathology and Occupational Health and by the Safety Services (respectively the 62% and the 18%). 87% of all the cases were histologically, 8% TC, 4% radiologically and only 1% clinically confirmed. The regional incidence rate (for 10(5) person-years, age standardized on the 1991 Italian population), has been estimated to be 1.98 in males and 0.88 in females. The highest rates were registered in Piacenza and Reggio Emilia province among men and Reggio Emilia and Ravenna province among women. 72% of cases have been classified as exposed to asbestos (64% occupationally and 8% as domestic/environmentally exposed).     

Histological types of malignant mesothelioma and asbestos exposure.

The Los Angeles County Cancer Surveillance Program abstracts hospital pathology records on almost all cases of cancer occurring in the county. Those cases of pleural and peritoneal mesothelioma that occurred between 1972 and 1978 were identified. Occupational histories were obtained from interviews, and the histopathology of the tumours was reviewed by a member of a mesothelioma reference panel who was unaware of the exposure histories. The relation of asbestos exposure to the three histological types of mesothelioma (epithelial, mesenchymal, and mixed) was studied among the 29 cases for whom occupational histories were available and who were also considered to have histopathology consistent with mesothelioma. The proportion of cases exposed to asbestos was high for both the epithelial (11/17, 65%) and mixed histological types (6/11, 55%). The single case of mesothelioma classified as a mesenchymal type was also exposed to asbestos. Cases who had worked in shipyards were represented in each of the three groups. In cases who had worked in asbestos production and manufacture an exclusively epithelial type of tumour was observed. In cases who had worked as insulators or in heating trades the histological type was predominantly (3/4) mixed. These data do not support the hypothesis that any specific histological type of mesothelioma is especially related to asbestos exposure.     

Malignant pleural mesothelioma in parts of Japan in relationship to asbestos exposure

Malignant pleural mesothelioma is induced by asbestos exposure. Many reports have described this situation in America and European countries, but a few have been published in Japan. In this study malignant pleural mesothelioma cases in hospitals located in an area facing the Seto Inland Sea were evaluated. A total of 106 patients were examined with 100 patients having had occupational exposure to asbestos and 6 patients without such histories of asbestos exposure. Ninety seven were male and 9 were female. Ages ranged from 41 to 87 yr with mean of 64.8+/-5.3 yr. Thirty seven cases showed epithelial type of tumor, 25 biphasic type and 15 showed sarcomatous. The remaining 23 cases had insufficient evidence for typing the tumor. The mean survival rate for all cases was 9.2+/-11.6 months. Fifty-one patients had occupational histories of shipyard work, 16 patients worked in asbestos cement piping, and the remainder were employed in miscellaneous jobs related asbestos exposure. The duration of asbestos exposure ranged up to 20 yr or longer with the mean of 17.2+/-8.9 yr and the average latent period for the occurrence of malignant pleural mesothelioma was more than 31 yr with the mean of 37.0+/-13.3 yr. Quantification of asbestos bodies in the lungs indicated a high concentration in most patients and the major types of asbestos fibers were crocidolite and amosite. Six cases appeared after exposure to chrysotile. These results indicated that ninety four percent of malignant pleural mesothelioma appeared due to the exposure to asbestos including crocidolite and amosite. The remainder may be blamed on exposure to chrysotile.