Asbestos exposure and related neoplasia. The 28 year experience of a major urban hospital

Lung Asbestos Bodies and Pulmonary Cancer in Subjects without Occupational Exposure

Lung asbestos bodies were searched for in 65 subjects with pulmonary cancer and without occupational exposure and in 65 matched controls. No significant association between the presence of asbestos bodies and occurrence of lung cancer was found. Nevertheless, adenocarcinoma was significantly associated with the presence of lung asbestos bodies in men. The latter result suggest that, even in non-professionally exposed subjects, the possibility of relationships between asbestos exposure and lung cancer cannot be excluded.

The prevalence of enlarged mediastinal lymph nodes in asbestos-exposed individuals: a CT study

Patients with cryptogenic fibrosing alveolitis have a higher prevalence of enlarged mediastinal lymph nodes compared with the normal population. To determine whether or not this observation applies to individuals with asbestos-induced pulmonary fibrosis the high resolution computed tomography (CT) scans of 14 patients with definite asbestosis and 11 age-matched cases with benign asbestos-induced pleural disease, but no lung disease, were re-imaged on soft tissue settings. The site, size and number of mediastinal lymph nodes equal to, or greater than, 1.2 cm were recorded. In the asbestosis group 14 out of 14 patients had at least one enlarged lymph node with an average number per individual of four (range 1-10). In the control group two out of 11 patients each had one minimally enlarged lymph node. We conclude that mediastinal lymph node enlargement occurs frequently in asbestosis: awareness of this is important in the investigation of malignant disease in patients with asbestosis.

Asbestos exposure and histologic cell types of lung cancer in surgical and autopsy series

A case-control study was carried out on 41 surgical and 106 autopsy histological tissue samples of lung cancer in men, in order to investigate the relationships between asbestos exposure and cell type of pulmonary carcinoma. Both occupational history (obtained by interviews of surgical patients or of the next-of-kin for deceased subjects) and lung asbestos body content (determined by optical count after hypochlorite digestion and membrane filtration of lung tissues) were considered as asbestos exposure indicators. No significant relationships were found in the surgical series after adjustment for smoking. The autopsy series showed a trend towards an association between lung adenocarcinoma and asbestos exposure indicators and a markedly higher agreement between the 2 kinds of indicators than that observed in the surgical series.

Diffuse malignant pleural mesothelioma in an urban hospital: clinical spectrum and trend in incidence over time

This retrospective analysis reviews the clinical experience of a major urban referral hospital with diffuse malignant pleural mesothelioma during the 14-year period from 1973 through 1986. Seventy-five cases of definite or equivocal mesothelioma were identified. There were four cases of primary malignant peritoneal mesothelioma, seven cases of benign fibrous mesothelioma, and 64 cases of diffuse malignant pleural mesothelioma. In 43 cases (67%) of diffuse malignant pleural mesothelioma, there was historic evidence of asbestos exposure. In 21 cases (33%), there was no known history of asbestos exposure. An increase in annual incidence of diffuse malignant pleural mesothelioma was observed over the study period, from three cases in 1973 to ten cases in 1986. Despite greater awareness of this disease, the diagnosis remains a difficult one to establish given the nonspecific symptoms, signs and radiographic appearance, variable histologic appearance, and poor diagnostic sensitivity and specificity of thoracentesis and closed pleural biopsy. Thoracotomy, thoracoscopy, and CT-guided needle biopsies gave higher yields and are the diagnostic measures of choice when diffuse malignant pleural mesothelioma is suspected.

Morphology of bronchogenic carcinoma in workers formerly exposed to crocidolite at Wittenoom Gorge in Western Australia

Cytology and histology material from 46 bronchogenic carcinomas occurring in ex-workers from the Wittenoom crocidolite mine and mill in Western Australia and a matched random sample of 234 other bronchogenic carcinomas occurring in Western Australia over the same period were reviewed by a single histopathologist without knowledge of asbestos exposure status. Squamous-cell carcinomas formed 45.7% of the cancers in the asbestos-exposed group but only 32.5% of the cancers in the comparison group. This difference could not be explained by differences in smoking history between the two groups of lung cancer patients or in the type of histopathological material available for review. The excess of squamous-cell cancers was observed in subjects both with and without parenchymal asbestosis.

Correlation of in vitro genotoxicity and oncogenicity induced by radiation and asbestos fibres

The in vitro cytotoxicity and oncogenic potential of both native and acid leached asbestos fibres were studied using the C3H 10T1/2 cell model. Both native and leached fibres induced a dose-dependent toxicity. At high fibre concentrations, acid leached fibres were significantly less toxic than their untreated counterparts. While asbestos fibres alone do not induce oncogenic transformation at the concentration examined, it was found that both leached and native fibres substantially enhanced the oncogenicity of gamma-irradiation in a more than additive fashion. Although no significant chromosomal aberrations or sister chromatid exchanges (SCE) were found in asbestos treated cultures, a significantly higher number of SCEs was observed in cells treated with both asbestos and radiation compared to cells receiving radiation alone. The results suggest that the enhancement in radiation induced oncogenicity by asbestos fibres may be attributed to the mere physical presence of the fibres rather than any chemical contaminants the fibres may contain. Furthermore, the carcinogenicity of asbestos may be unrelated to genotoxicity.

Histologic type of lung cancer and asbestos exposure

The histologic types of lung cancer in 855 patients (747 men and 107 women) from three hospitals and one international study of insulation workers were evaluated. Of these, 196 cases had asbestos exposure. About one half of the cases were diagnosed from surgical slides and one half from autopsy slides. Squamous cell carcinoma constituted the largest percentage of tumor types and was found with the same frequency in exposed and nonexposed groups. Small cell carcinoma was found in 25% of the exposed and in 15% of the nonexposed patients. Upper lung sites were involved in about two thirds of the cases with asbestos exposure and lower lobes in the other one third. There was little difference in histologic type in cases regardless of whether upper or lower lobes were involved. Cigarette smokers who smoked until their cancer diagnosis showed no difference in histologic type by amount smoked, and slight but not statistically significant differences from ex-cigarette smokers.

Parietal pleural plaques, asbestos bodies, and neoplasia. A clinical, pathologic, and roentgenographic correlation of 25 consecutive cases

An investigation was made to correlate autopsy and roentgenographic findings of pleural plaques with occupational exposure to asbestos and occurrence of respiratory tract tumors. Of the 434 autopsies performed over a 2 1/2 year period, 25 (5.8 percent) had pleural plaques but no gross evidence of parenchymal fibrosis. Review of the posterior-anterior chest roentgenograms using the International Labor Office criteria for classification of pneumoconiosis (1980) revealed that only seven of the 25 cases had detectable pleural thickening or calcification, which demonstrates the poor sensitivity of standard x-ray films. There was no detectable difference in frequency of known or presumed exposure to asbestos between the pleural plaque cases and controls as determined by occupational information obtained from chart review. Asbestos bodies were identified in lung tissue digests from all 25 cases with pleural plaques, and exceeded the normal range for our laboratory in 14 cases (56 percent). Of the 25 cases with pleural plaques, four also had bronchogenic and three had laryngeal carcinoma. The prevalence of bronchogenic carcinoma in patients with plaques was not different from those without plaques (p greater than 0.50). However, the association between plaques and laryngeal carcinoma was highly significant (p = 0.004).

Glycosaminoglycans of pleural mesothelioma: a possible biochemical variant containing chondroitin sulfate

Glycosaminoglycans of a malignant pleural mesothelioma have been characterized histochemically and biochemically and compared with those of normal lung, pleural plaque, lung carcinoma, and other connective tissue neoplasms. Chondroitin sulfate constituted the major glycosaminoglycan (approximately 80% of total) present in the pleural mesothelioma while hyaluronic acid was present in only trace amounts (approximately 3% of total). In particular chondroitin 6-sulfate was the predominant isomer, constituting 80% of the total chondroitin sulfate. Control tissue exhibited different proportions of glycosaminoglycans and none of them contained as high an absolute concentration of chondroitin sulfate as the mesothelioma. These findings differ from previous reports demonstrating increased concentration of hyaluronic acid in mesothelioma and suggest the possible existence of a biochemically different form of this neoplasm.

Immunoblastic lymphadenopathy and asbestosis

Immunoblastic lymphadenopathy was diagnosed in a 71-year-old white man who had weakness, with weight loss, fever, cough, and generalized lymphadenopathy. The patient had a long occupational history of shipyard work. Diagnosis of asbestosis was made clinically by chest x-ray, and ferruginous bodies were found in the lung at autopsy. Recent reports have suggested a possible association between asbestos exposure and lymphoproliferative neoplasms. Chronic antigenic stimulation by asbestos could predispose one to the immunoproliferative disorder seen in this patient or be responsible for it. The possible significance of this relationship, previously unreported, is discussed for future consideration.