Continuing increase in mesothelioma mortality in Britain.

Dietary Intake and the Risk of Malignant Mesothelioma (Beta Carotene Reduces Meso Risk!).

Pleural mesotheliomas are underreported as occupational cancer in Sweden.

Pleural Plaques and Risk for Bronchial Carcinoma and Mesothelioma. A prospective study.

Mesothelioma: is asbestos exposure the only cause?

Malignant mesothelioma associated with low pulmonary tissue asbestos burdens: a light and scanning electron microscopic analysis of 18 cases.

Aspects of histopathologic subtype as a prognostic factor in 85 pleural mesotheliomas.

Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients.

Asbestos fiber type in malignant mesothelioma: an analytical scanning electron microscopic study of 94 cases.

Malignant mesothelioma in women.

Concurrent mesothelioma and adenocarcinoma of the lung in a patient with asbestosis.

Reactive Mesothelial Hyperplasia vs Mesothelioma, Including Mesothelioma in Situ: a Brief Review.

"Idiopathic" Mesotheliomas Questioned: Is there such a thing as "background" level asbestos exposures?

Continuing increase in mesothelioma mortality in Britain.
Abstract: Mesothelioma is closely related to exposure to asbestos, and mesothelioma mortality can be taken as an index of past exposure to asbestos in the population. We analyzed mesothelioma mortality since 1968 to assess the current state of the mesothelioma epidemic, and to predict its future course. We found that rates of mesothelioma in men formed a clear pattern defined by age and date of birth. Rates rose steeply with age showing a very similar pattern in all five-year birth cohorts. By date of birth, rates increased from mid-1893 to mid-1948, and then fell. Relative to the 1943-48 cohort, the risk for the 1948-53 cohort is 0.79 and for the 1953-58 cohort 0.48. Despite these falls, if the age profile of rates for these cohorts follows the pattern of past cohorts, their predicted lifetime mesothelioma risks will be 1.3%, 1.0%, and 0.6%. Combining projections for all cohorts results in a peak of annual male mesothelioma deaths in about the year 2020 of between 2700 and 3300 deaths. If diagnostic trend is responsible for a 20% growth in recorded cases every 5 years--an extreme but arguable case--and if this trend has now ceased, the peak of annual male deaths will be reduced to 1300, reached around the year 2010. Analysis of occupations recorded on death certificates indicate that building workers, especially plumbers and gas fitters, carpenters and electricians are the largest high-risk group. These data indicate that mesothelioma deaths will continue to increase for at least 15 and more likely 25 years. For the worst affected cohorts--men born in the 1940s--mesothelioma may account for around 1% of all deaths. Asbestos exposure at work in construction and building maintenance will account for a large proportion of these deaths, and it is important that such workers should be aware of the risks and take appropriate precautions.

Author: Peto J, Hodgson JT, Matthews FE, Jones JR
Section of Epidemiology, Institute of Cancer Research, Belmont, Surrey, UK.
Lancet
1995 Mar 4

Dietary Intake and the Risk of Malignant Mesothelioma (Beta Carotene Reduces Meso Risk!)
Abstract: A high consumption of fruit and vegetables reduces the risk of several types of cancer. There is little information on the association between dietary intake and mesothelioma. A hospital-based case-control study of 94 men and women with malignant mesothelioma and 64 control patients without cancer was conducted to determine the odds associated with consumption of carotenoid-containing fruits and vegetables. After statistical adjustment for occupational asbestos exposure, the odds ratio was 0.2 [95% confidence interval (CI) 0.1-0.8] for carrot consumption and 0.5 (95% CI 0.2-1.4) for tomato consumption. However, the frequency of consuming other foods that have a high vitamin A or carotenoid content was not associated with a decreased risk of cancer. These results provide some justification for the hypothesis that provitamin A or beta-carotene may decrease the risk of mesothelioma. The body mass index was unrelated to the risk of mesothelioma.

Author: Muscat JE, Huncharek M
Division of Epidemiology, American Health Foundation, New York, NY, USA.
Br J Cancer
1996 May

Pleural mesotheliomas are underreported as occupational cancer in Sweden.
Abstract: The aim of this study was to estimate to what degree malignant pleural mesotheliomas were reported as occupational cancers. The study included all malignant pleural mesotheliomas (n = 210) found in the Cancer Registry 1980-1989 from four Swedish counties. Whether or not a case was reported as occupational cancer was found in the Swedish Register of Reported Occupational Diseases. To evaluate the presence of exposure histories, the chest department files for 58 mesotheliomas from one county were reviewed. The reporting was low, with only 75 mesotheliomas (36%) reported. All the cases were men, and for the men, the reporting frequency was 42%. The reporting was significantly lower for the last part of the decade than for the first part. The reporting frequency decreased with age. In the review of the chest department files, an exposure history was found in 93% of the reported cases and in 47% of the unreported cases. It is concluded that physicians must give more priority to exposure histories in patients with pleural mesotheliomas.

Author: Andersson E, Toren K
Department of Occupational Medicine, Sahlgrenska University Hospital, S:t Goteborg, Sweden.
Am J Ind Med
1995 Apr

Pleural Plaques and Risk for Bronchial Carcinoma and Mesothelioma. A prospective study.
Abstract: From the general population in the county of Uppsala, Sweden, 1,596 men with pleural plaques fulfilling strict radiologic criteria were identified from 1963 until June 1985. The men have been followed prospectively for 16,369 person-years. The number of mesotheliomas and bronchial carcinomas was compared with the age- and year-specific expected incidence from the official cancer registry of Sweden. Fifty bronchial carcinomas occurred, while 32.1 were expected after correction for smoking habits, a difference which was statistically significant. Patients with radiologic asbestosis were over-represented among those with bronchial carcinoma. The risk for patients with pleural plaques without asbestosis was increased 1.4 times, which was statistically significant. There were 9 mesotheliomas, while only 0.8 were expected. The mean latency time from first exposure to diagnosis of bronchial cancer was 44.1 years and for mesothelioma was 48.1 years.
Thus, pleural plaques on the chest roentgenogram indicate significant exposure to asbestos, with an increased risk for mesothelioma and possibly also for bronchial carcinoma. Any person found to have plaques on chest roentgenogram should be informed of them and should be persuaded to stop smoking.

Author: Hillerdal G
Department of Lung Medicine, Uppsala University, Akademiska Sjukhuset, Sweden.
Chest
1994 Jan

Mesothelioma: is asbestos exposure the only cause?
Abstract: BACKGROUND: Although a causal association between mesothelioma and occupational exposure to asbestos is beyond dispute, nearly all population-based studies of mesothelioma have found some proportion of cases with no history of asbestos exposure. DATA: Incidences of mesothelioma in men and women not occupationally exposed to asbestos for the period 1980-1985 were generated from: (i) estimates of occupational exposure to asbestos in the general male population, obtained from population-based controls in a case-control study of incident cancer in South Australia; and (ii) National Mesothelioma Surveillance Program data. The incidence in men not occupationally exposed was 8.5 per 1,000,000 person-years, compared with 2.6 per 1,000,000 person-years in women, a difference of 5.9 per 1,000,000 person-years (90% confidence interval, 4.8-7.2).
CONCLUSION: Mesothelioma without a history of asbestos exposure may be caused by asbestos in the general environment, but this fails to explain why such cases occur more commonly in men. Alternative explanations include the existence of another independent cause of mesothelioma, or of a co-factor which, combined with "environmental" levels of asbestos exposure, constitutes a sufficient cause. Such a risk factor is likely to be occupational, in which case mesothelioma may be expected to occur even after occupational asbestos exposures have been eliminated.
Gun RT
Department of Community Medicine, University of Adelaide, SA.
Med J Aust
1995 Apr 17

Malignant mesothelioma associated with low pulmonary tissue asbestos burdens: a light and scanning electron microscopic analysis of 18 cases.
Abstract: Most malignant mesothelioma cases are associated with pulmonary asbestos body (AB) counts significantly greater than those of the general population. However, the question remains whether malignant mesothelioma cases associated with "normal" AB counts (i.e., indistinguishable from the general population) represent background incidence levels or are, actually, asbestos related. We performed AB counts (by light microscopy) and mineral fiber analysis (by scanning electron microscopy) in 18 mesothelioma cases with AB counts within our normal range (0 to 20 AB/G wet lung) and in 19 "control" cases. Our study demonstrated that approximately one-third (6 of 18) of the mesothelioma cases have asbestos fiber burdens greater than 95% of the control levels. These results suggest that these six mesothelioma cases may be asbestos related despite AB counts similar to those of the general population. An asbestos etiology was suggested in three additional cases, but too few amphibole fibers were identified in these cases to be certain of a value above background. The remaining nine cases showed no evidence of an asbestos etiology. Electron microscopic analysis of pulmonary mineral fibers may be required to differentiate asbestos-related mesotheliomas from non-asbestos-related cases when AB counts are within the range of background values.

Author: Srebro SH, Roggli VL, Samsa GP
Department of Pathology, Durham Veterans' Administration, North Carolina, USA.
Mod Pathol
Date Of Publication: 1995 Aug

Aspects of histopathologic subtype as a prognostic factor in 85 pleural mesotheliomas
Abstract: BACKGROUND: The prognosis of patients with pleural mesothelioma is more dependent on "pretreatment factors" than on the effect of therapeutic interventions. Histopathologic subtype is one of several important prognostic factors in pleural mesothelioma, and several studies indicate that the epithelial subtype of pleural mesotheliomas has a more favorable prognosis than the sarcomatoid. In this study, we retrospectively evaluated qualitative and quantitative aspects of the tissue specimens used for histopathologic diagnosis in 85 patients with pleural mesothelioma.
MATERIALS AND METHODS: The prognostic roles of two different histopathologic classification systems were evaluated in 85 consecutive cases of pleural mesotheliomas. Efficiency of different diagnostic procedures, influence of the size of the biopsy specimens on the histopathologic diagnosis, and immunohistochemical profiles for histopathologic subtypes of mesotheliomas were also evaluated.

RESULTS: Patients with pure epithelial mesotheliomas (n = 35), and especially those with the tubulopapillary subtype (n = 18) of epithelial mesotheliomas, survived significantly longer than those with a sarcomatoid component (n = 50). With larger biopsy specimens (surgical biopsy, autopsy), more tumors were classified as biphasic (36/78 vs 9/44, p < 0.005). The sarcomatoid mesotheliomas comprised about 20% of the tumors regardless of type of biopsy. Staining intensity for cytokeratin CAM 5.2 was equal in all types of mesotheliomas, while intensity with cytokeratin AE1/AE3 decreased from the epithelial to the sarcomatoid mesotheliomas. Staining with vimentin was most intense among the sarcomatoid mesotheliomas, while with epithelial membrane antigen it was most intense among the epithelial mesotheliomas.
CONCLUSIONS: The quality of the biopsy specimens has considerable impact on the possibility to arrive at a correct histopathologic diagnosis. Based on our results, we suggest tubulopapillary B>mesotheliomas be regarded as "low-grade mesotheliomas" and other types, including the epithelioid type of epithelial mesotheliomas, as "high-grade mesotheliomas." This should be taken into account when designing clinical trials.
Author: Johansson L, Linden CJ
Department of Pathology, University Hospital, Lund, Sweden.
Chest
1996 Jan

Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients.
Abstract: OBJECTIVE. Malignant pleural mesothelioma in rural Turkey frequently results from environmental exposure to tremolite asbestos or fibrous zeolite (erionite). The aim of this study was to determine the CT features of malignant pleural mesothelioma in patients exposed to asbestos or erionite. MATERIALS AND METHODS. The CT scans of 84 patients with proved malignant pleural mesothelioma were retrospectively evaluated. Twenty patients (24%) had been exposed to erionite and 64 patients (76%) had been exposed to asbestos. The CT scans were interpreted by seven observers who did not know the clinical or pathologic findings. RESULTS. CT scans showed either unilateral pleural thickening or pleural nodules/masses in all patients. Pleural nodules were present in 25 patients (30%) and pleural masses in 44 patients (52%). Pleural effusion was found in 61 patients (73%), mediastinal pleural involvement in 78 (93%), pleural calcifications in 52 (62%), involvement of the interlobar fissures in 64 (76%), and volume contraction in 61 (73%). Reduced size of the hemithorax was significantly correlated with chest wall involvement. On the basis of CT findings, the pre-assigned staging was changed in 21 patients (25%), including 44% of the patients with disease that had been classified as stage I. CT findings were not significantly different between the patients exposed to erionite and those exposed to asbestos.
CONCLUSION. The most common CT findings in cases of malignant pleural mesothelioma were unilateral pleural thickening or pleural nodules/masses with or without effusion. CT provided valuable information on the extent of the disease, which was important for staging. Although the CT features are not pathognomonic, they provide valuable clues to the diagnosis in patients who have been exposed to mineral fibers.
Author: Sahin AA, Coplu L, Selcuk ZT
Department of Chest Diseases, Hacettepe University, School of Medicine, Ankara, Turkey.
AJR Am J Roentgenol
1993 Sep

Asbestos fiber type in malignant mesothelioma: an analytical scanning electron microscopic study of 94 cases
Abstract: Although the association between asbestos exposure and malignant mesothelioma is indisputable, controversy continues regarding the relative contribution of the various types of asbestos fibers to the development of mesothelioma. We examined the types of asbestos fibers recovered from lung parenchyma in more than 90 cases of malignant mesothelioma from the United States, using an analytical scanning electron microscope. Almost half of the patients were former asbestos insulators or shipyard workers. The fibers were recovered from lung tissues obtained at autopsy or surgical resection by means of a sodium hypochlorite digestion procedure. Amosite asbestos was identified in 81% of the cases and accounted for 58% of all fibers 5 microns or greater in length. Tremolite/actinolite/anthophyllite were identified in 55% of the cases and accounted for 10% of all fiber types. Chrysotile was identified in 21% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Crocidolite was found in 16% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Nonasbestos mineral fibers (commonly found in the lungs of the general population) were observed in 71% of the cases and accounted for 25% of all fibers 5 microns or greater in length. The findings in this study are at odds with the assertion that crocidolite asbestos is responsible for most mesotheliomas in the United States.
Author: Roggli VL, Pratt PC, Brody AR,
Durham Veterans Administration, NC.
Am J Ind Med
1993 Apr

Malignant mesothelioma in women.
Abstract: BACKGROUND: Malignant mesothelioma reportedly shows different epidemiology and pathology in females, and a proportion are believed to arise spontaneously.
METHODS: One hundred and seventy seven cases of malignant mesothelioma in females were reviewed, examined by histochemistry and immunohistochemistry, assessed for asbestosis and lung fibre burden by transmission electron microscopy with energy dispersive x ray analysis, and compared with 31 female controls.
RESULTS: Two of one hundred and three cases tested for carcinoembryonic antigen were positive and were excluded from further analysis. Tumour cases showed increased amphibole burdens; in those in whom exposure information was known, 74 (80%) of 93 patients had a history of exposure to asbestos. Seventy two (47%) of 152 patients had lung fibrosis. Tumour site and histological type were little different from those reported in adult males. Mixed type histological pattern, lung fibrosis, and peritoneal site were associated with heavier lung asbestos burdens, but not exclusively. Thirty five (30%) of 117 patients had amphibole burdens of less than 2 x 10(6) fibres/g; the sites affected and the histological pattern of tumors in this group were similar to those in cases with amphibole fibre counts of > or = 2 x 10(6)/g lung. A higher lung amphibole burden than the mean burden in control females was found in 115 (98%) of 117 patients tested.
CONCLUSIONS: The pathology of malignant mesothelioma appears to be similar in women and in men, and in cases associated and unassociated with asbestos.
Dawson A
Department of Histopathology, Llandough Hospital, Penarth, South Glamorgan, UK.
Thorax
1993 Mar

Concurrent mesothelioma and adenocarcinoma of the lung in a patient with asbestosis
Abstract: We report the apparently unique simultaneous development of a mesothelioma and an adenocarcinoma of the lung in a patient with asbestosis. Pathologists should be aware that very rarely these two malignancies may occur concurrently, an event with potential prognostic, therapeutic, and medical-legal implications for the patient and his family. Although occupational asbestos exposure is well recognized as a risk factor in the development of both mesothelioma and lung carcinoma, this case report emphasizes the rarity of the synchronous occurrence of these tumors in asbestos exposed individuals suggesting that the mechanism by which asbestos fibers induce lung carcinoma is different from that by which they induce mesothelioma.
Author: Cagle PT, Wessels R, Greenberg SD
Department of Pathology, Baylor College of Medicine, Houston, Texas.
Mod Pathol
1993 July

Reactive Mesothelial Hyperplasia vs Mesothelioma, Including Mesothelioma in Situ: a Brief Review
Abstract: In biopsy tissue, discrimination between reactive mesothelial hyperplasia and epithelial mesothelioma can pose a major problem for the surgical pathologist. Confidence in the diagnosis is often proportional to the amount of tissue available for study and depends largely on findings of invasion and the extent and cytologic atypia of the lesion, because there is no marker specific for the mesothelium and that discriminates consistently among normal, hyperplastic, and neoplastic mesothelial tissue. Therefore, mesothelioma in situ is diagnosable only when invasive epithelial mesothelioma is demonstrable in the same specimen, in a follow-up biopsy specimen, or at autopsy. Comparison of 22 cases of mesothelioma in situ that fulfill these requirements for diagnosis with 141 invasive mesotheliomas and 78 reactive mesothelioses indicates that strong linear membrane-related labeling for epithelial membrane antigen and silver-labeled nucleolar organizer region-positive material that occupies 0.6677 microm2 or more of the nucleus in an atypical in situ mesothelial lesion of the pleura are found consistently in neoplastic mesothelial cells. Although these findings may engender suspicion of mesothelioma in situ in high-risk persons, the criteria for diagnosis of pure mesothelial lesions of this type are still under study. Mesothelioma in situ should be considered proved only when unequivocal invasion is identified in a different area of the pleura or at a different time; a diagnosis of pure mesothelioma in situ should not be made in patients not exposed to asbestos.
Address Department of Anatomical Pathology, Flinders Medical Centre, Adelaide South Australia, Australia.
Author Henderson DW; Shilkin KB; Whitaker D
Source Am J Clin Pathol, 110(3):397-404 1998 Sep