Survival of asbestos insulation workers with mesothelioma

Malignant mesothelioma is a lethal disease. It is rare in the general population; however, workers exposed to asbestos suffer significant burdens of the neoplasm. The survival time of 457 consecutive fatal cases of pleural and peritoneal mesothelioma that occurred among 17,800 asbestos insulation workers observed prospectively from 1 January 1967 to 1 January 1987 was studied. Mean survival time from initial presentation of the disease to death was 11.4 months for the pleural mesothelioma patients compared with 7.4 months for the peritoneal group. This difference was statistically significant. Mean survival time from diagnosis to death was shorter for both groups of patients: 8.4 months for pleural mesothelioma v 5.8 months for the peritoneal cases. In conclusion, survival time in mesothelioma patients is short; most die within a year from the onset of the initial symptoms. No effective therapy is yet available.     

Cystic mesothelioma of the peritoneum

We report a case of cystic mesothelioma of the peritoneum (CMP), a rare tumor. The magnetic resonance imaging (MRI) findings and the histochemical features were studied. The patient was an 18-year-old women who presented with upper abdominal pain. Abdominal ultrasonography and computed tomography showed a well defined cystic mass with a solid papillary projection in its lumen. MRI of the cyst showed high intensity on T2- and proton weighted images and low intensity on T1-weighted images, and the solid projection showed low intensity on T2- and proton-weighted images and slight low intensity on T1-weighted images, on which it was well enhanced. The lesion was suspected to be a benign cyst, such as a hemangioma, lymphangioma, or a splenic or pancreatic cyst. Complete surgical resection was performed. The resected specimen consisted of a unilocular cystic mass, with a solid projection, weighing 260 g and measuring 10 cm in diameter. The final diagnosis, arrived at by histopathological examination, was low-grade malignant CMP. The tumor cells were strongly positive for keratin, weakly positive for vimentin, and negative for epithelial membranous antigen. The patient is now well and symptom-free with no recurrence 19 months after operation. CMP is a rare tumor; only 12 cases have previously been reported in Japan.     

Incidence of mesothelioma among asbestos plant workers

Pleural mesothelioma is a very rare neoplasm. Its aetiology is connected with exposure to asbestos dust. In the paper 12 cases are presented of pleural mesothelioma out of 34 cases of lung cancer diagnosed in Asbestos-Cement Factory workers and in persons living in the vicinity of this plant. The attention is paid to the increase of incidence of pleural mesothelioma and health risk connected with it for the population of that region, caused by the production of the plant.     

A case of malignant mesothelioma of the pleura and the peritoneum detected by sudden onset of back pain and pleural effusion and ascites

A case of malignant mesothelioma of the pleura and the peritoneum is reported. In April 1996, a 40-year-old men noticed sudden onset of back pain. Radiographic examinations and MRI revealed pleural effusions, ascites, ringed enhanced tumorous lesions in the right posterior diaphragm along the abdominal aorta, and marked thickening of the right diaphragm with moderate signal intensity. On thoracoscopic surgery, there were white small nodules on the intercostal parietal pleura. Tumor cells of a tubulopapillary pattern had large rounded nuclei and eosinophilic cytoplasms in a partially glandlike arrangement. Cytoplasms of tumor cells stained for alcian blue disappeared after hyaluronidase digestion. Immunohistochemical examinations showed positive staining for keratin but negative for CEA. Electron micrographs showed numerous long thin microvilli, desmosomes and intermediate tonofilaments. From these findings, malignant mesothelioma was diagnosed. The malignant mesothelioma cells of the pleura in this case were considered to disseminate the peritoneum directly through the diaphragm or its lymphatic canals. MRI and thoracoscopic surgery were useful for the demonstration of the pleural disseminations and abdominal invasions.     

Lung cancer risk among beauticians and other female workers: brief communication

Lung cancer risk among occupational groups of women was reviewed. A previous suggestion of a sixfold risk of developing lung cancer among beauticians was not confirmed; however, an approximately twofold risk was found.     

Malignant mesothelioma of the pleura. Morphometric study

Between April 1994 and October 1996 on account of complicated obstruction of the lacrimal pathways temporarily into the lacrimal efferent system 144 silicone cannulas were inserted in 127 children aged 4 months to 9 years. A standard procedure was used, with the children under general inhalation anaesthesia, in collaboration of an ophthalmologist and otorhinolaryngologist using endonasal optics. By October 1996 100 cannulas were extubated, on average after 4.1 months. The effectiveness of the procedure evaluated on the basis of clinical manifestations and the Dye Disappearance test is 81%.     

Lung cancer among steelworkers in Ontario

A population-based case-control study was carried out to follow up observations of increased lung cancer risk in the steel pouring areas of two Ontario steel mills. Study subjects were all men, aged 45-75 years, who died of lung cancer in the cities of Hamilton or Sault Ste-Marie, Ontario from 1979-1988. Nine hundred sixty-seven lung cancer victims were matched with 2,827 control subjects who died of other causes. Work histories were provided by the employers of steelworkers. In comparison with other residents of their cities, the relative risk of death from lung cancer was 0.85 (95% confidence interval [CI]: 0.58-1.23) for steelworkers in Sault-Ste Marie and was 1.10 (95% CI: 0.89-1.37) for steelworkers in Hamilton. In internal comparisons within the steel companies, increased lung cancer risk was observed among foundry, coke oven, and pouring pit workers. Retrospective hygiene assessment suggested that the increased risk of lung cancer among steel pourers might be related to the use of tar-based mold coating agents or to exposure to mineral fibers.     

Lung cancer mortality in a French cohort of hard-metal workers

A cohort mortality study was carried out among workers of a plant producing hard metals using cobalt as a binder. This study was aimed at assessing possible lung cancer risks in relation with cobalt exposure. Seven hundred nine male workers with at least 1 year of employment were included in the cohort and followed for mortality from 1956 to 1989. Job histories were provided by the administration of the plant, whereas smoking habits were collected from medical records and by interview. The causes of deaths were ascertained from hospital and general practitioner records. The observed numbers of deaths (obs) were compared with the expected based on national rates with adjustment for age, sex, and calendar time (standardized mortality ratio; SMR). The overall mortality did not differ from that expected (obs = 75, SMR = 1.05), whereas mortality due to lung cancer was in significant excess (obs = 10, SMR = 2.13). This excess was higher among workers employed in the areas with the highest exposure (obs = 6, SMR = 5.03). No trend was observed, however, with duration of employment or time since first employment. Smoking data were available for 81% of the workers and 69% of the deceased and showed that smoking alone does not account for these lung cancer excesses, yet, because of the small numbers involved, no firm conclusion should be drawn from this study.     

Hypertension and long-term cancer incidence and mortality among Swedish men

OBJECTIVE: To examine incidence of cancer and cancer mortality in relation to high blood pressure. DESIGN: A longitudinal study of middle-aged men from a random population sample. SETTING: G?teborg, Sweden. SUBJECTS: We studied 7396 men aged 47-55 years without diagnosed cancer at baseline (1970-1973). MAIN OUTCOME MEASURES: Incidence of cancer and mortality from cancer. RESULTS: By the end of December 1992, 1401 men had been diagnosed with cancer at any site and 651 had died from cancer. Of the men in the highest fifth of the systolic blood pressure distribution (above 166 mmHg) 126 per 10000 observation years were diagnosed with cancer at any site, compared with 91 per 10000 in the lowest fifth [below 130 mmHg; relative risk after adjustment for age, smoking, body mass index, treatment for hypertension and leisure time physical activity 1.41 (95% confidence interval 1.19-1.68); P for trend 0.0001]. Of men in the highest fifth, 55 per 10000 observation years died from cancer, compared with 42 in the lowest [adjusted relative risk 1.41 (1.09-1.82); P for trend 0.01]. Several types of tumour tended to be more common among men with hypertension, but only genito-urinary cancers [age-adjusted relative risk 1.39 (1.04-1.85)] and non-melanoma skin cancer [age-adjusted relative risk 1.98 (1.12-3.51)] were significantly so. Findings were similar for diastolic blood pressure and if data for the first 5 years of follow-up were excluded. There was an increase in risk of cancer also during the first 5 years [adjusted relative risk 1.80 (1.10-2.92) for systolic blood pressure and 1.77 (1.05-2.99) for diastolic blood pressure]. CONCLUSIONS: We found an excess risk of cancer and of death from cancer for men with high blood pressure. Although the increase in risk was comparatively modest, the findings are of public health importance, insofar as both hypertension and cancer are common conditions.     

Lung function changes among recycling workers exposed to organic dust

OBJECTIVE: To describe the feasibility of diagnosing fetal congenital heart defects by transvaginal ultrasonography during the first trimester of pregnancy. METHODS: Pregnant women presenting to the Ultrasonographic Unit at the Chaim Sheba Medical Center who had a diagnosis of fetal heart defects were reviewed retrospectively. Attention was paid to prenatal ultrasound studies, karyotype, and pathologic examinations. RESULTS: Using high-resolution transvaginal ultrasonography, we were able to detect fetal tachycardia (one case), ectopia cordis with ventricular septal defect (one case), atrioventricular septal defect (two cases), ventricular septal defect with persistent truncus arteriosus (one case), tetralogy of Fallot (two cases), and large right atrium with unguarded tricuspid valve (Uhl disease) (one case). Seven of these fetuses had normal karyotypes and all showed additional sonographic abnormalities, including septated cystic hygroma (three cases), hydrops (ascites and pericardial effusions) (two cases), omphalocele (one case), and bilateral agenesis of kidneys (one case). Only one fetus with an abnormal karyotype (45,XO) showed a combination of septated cystic hygroma with hydrops. CONCLUSIONS: High-resolution duplex Doppler transvaginal ultrasonography during the first trimester of pregnancy seems to be a useful diagnostic method for detecting some congenital heart diseases.     

Cancer incidence of workers in the Swedish petroleum industry

OBJECTIVES: To estimate the risk of cancer due to occupational exposure to petroleum products in the Swedish transport and refinery industries. METHODS: In a retrospective cohort study the cancer incidence in 4128 men and 191 women, who had worked for at least one year in the petroleum industry, was compared with the incidence in the general population. The job titles and employment times for each person were found in personal files in the industries. The men had on average worked in jobs exposed to petroleum for 11.6 years at the end of the observation period. The cases of cancer were identified by record linkage with the Swedish cancer register. RESULTS: In total there were 146 cases of cancer v 157.6 expected (standardised mortality ratio (SMR) 0.93 90% confidence interval (90% CI) 0.80 to 1.1). Operators at refineries had an increased risk of leukaemia (6 cases v 1.7 expected, 90% CI of relative risk (RR) 1.5 to 7.0). Five of the six cases had started to work at the refineries in the 1950s or later. No other significantly increased risk of cancer was found. Distribution workers had a decreased incidence of lung cancer (no cases, 90% CI of RR 0 to 0.4). CONCLUSIONS: Operators at Swedish refineries had an increased risk of leukaemia. A possible cause is exposure to benzene. There was no increased risk of leukaemia in distribution workers. Distribution workers had a decreased risk of lung cancer.     

Localization of membrane-associated sialomucin on the free surface of mesothelial cells of the pleura, pericardium, and peritoneum

The effects of insulin and insulin-like growth factors (IGFs) I and II on fetal and foal chondrocytes were investigated in vitro. Chondrocytes from the lateral trochlear ridge of the distal femur were obtained from 2 fetuses (280 and 320 days gestation) and one 4-day-old foal and cultured. Membrane proteins consistent with type 1 and type 2 IGF receptors were demonstrated by radioligand cross linking and equilibrium binding analysis. It was demonstrated that both IGF-I and IGF-II acted as mitogens for isolated equine chondrocytes when present as the sole mitogenic factor in monolayer culture. It was further shown that whereas insulin was able to promote the survival and expansion of cell populations of chondrocytes in culture there was significantly reduced mitogenic stimulation compared to the IGFs. These results suggest that the role of insulin in growth cartilage may be to promote chondrocyte survival, or to suppress differentiation/apoptosis. This supports the hypothesis that relative hyperinsulinaemia may be a contributory factor to equine dyschondroplasia (osteochondrosis). Understanding of contributory, and possibly triggering factors such as this may allow the development of modified methods of husbandry which minimise the risk of disease in populations with a known predisposition.     

Value of cytokeratin 5/6 immunostaining in distinguishing epithelial mesothelioma of the pleura from lung adenocarcinoma

The immunohistochemical diagnosis of mesothelioma is commonly made by using a battery of antibodies that reacts with lung adenocarcinomas but not with epithelial mesotheliomas. Only recently have markers that are often expressed in mesotheliomas but not in adenocarcinomas been recognized. Some of these markers, however, require frozen tissue sections, whereas others are not commercially available, or their value remains controversial. In a recent publication, it was suggested that immunostaining for cytokeratin 5/6 could assist in distinguishing epithelial mesothelioma from lung adenocarcinoma. To determine the practical value of cytokeratin 5/6 immunostaining in the diagnosis of mesothelioma, 40 formalin-fixed, paraffin-embedded epithelial pleural mesotheliomas, 30 pulmonary adenocarcinomas, 93 nonpulmonary adenocarcinomas, 15 squamous carcinomas of the lung, 5 large cell undifferentiated carcinomas of the lung, and 12 metastatic transitional cell carcinomas to the lung were stained with the same antibody, which was obtained from a commercial source. Cytokeratin 5/6 reactivity was observed in all 40 mesotheliomas, but there was none in any of the 30 pulmonary adenocarcinomas. Focal or weak reactivity was observed in 14 of 93 nonpulmonary adenocarcinomas (10 of 30 ovarian, 2 of 10 endometrial, 1 of 18 breast, I of 7 thyroid, 0 of 10 kidney, 0 of 10 colonic, and 0 of 8 prostatic). All 15 squamous carcinomas of the lung, 6 of 12 transitional cell carcinomas metastatic to the lung, and 3 of 5 large cell undifferentiated carcinomas of the lung expressed cytokeratin 5/6. It is concluded that cytokeratin 5/6 immunostaining is not only useful in separating epithelial pleural mesotheliomas from pulmonary adenocarcinomas but also can assist in distinguishing epithelial mesotheliomas from nonpulmonary adenocarcinomas metastatic to the pleura.     

Peer discussions of cancer among Hispanic migrant farm workers

Hispanic migrant agricultural workers' exposure to pesticides and other agrichemicals places them at increased risk for a variety of acute and chronic conditions, including cancer. As a socioeconomically disadvantaged group, migrant workers also face many barriers to effective cancer control. In 1992, a series of focus groups was held with 55 Hispanic migrant agricultural workers (22 women, 33 men) in central Wisconsin to gather information on their knowledge and attitudes regarding cancer etiology and treatment, their practices regarding cancer screening and early detection, and their concerns regarding occupational exposure to pesticides. Beliefs that pesticides are toxic and can cause health problems were common among participants. In addition, however, participants reported that they are reluctant to demand occupational protections to which they are entitled because they are afraid of losing their jobs. Study results also suggest that barriers to effective primary and secondary prevention of cancer in this Hispanic migrant agricultural worker population include knowledge and information barriers, cultural barriers, and socioeconomic barriers. A lack of knowledge and information regarding the causes of cancer, its prevention, and its early detection and treatment was evident among participants, which in turn was reflected in strong fatalistic attitudes toward the disease. Cultural barriers included attitudes of embarrassment and shame associated with physical examinations and women's strong discomfort with male clinicians. Socioeconomic barriers to secondary prevention included the cost of obtaining health services, time constraints associated with the need to work and long working days, and a lack of transportation. Efforts to improve cancer screening as well as other preventive health services in the Hispanic migrant agricultural worker population must acknowledge these barriers and address as many of them as possible to be successful.     

Excess hepatobiliary cancer mortality among munitions workers exposed to dinitrotoluene

This study was conducted to determine the sex of buffalo embryos produced in vitro by amplifying male specific DNA sequences using the polymerase chain reaction (PCR). This method uses three different pairs of bovine Y-chromosome specific primers and a pair of bovine satellite specific primers. Buffalo in vitro fertilized embryos at the 4-cell to blastocyst stage were collected at days 3, 4, 6, and 8 postinsemination, and the sex of each embryo was determined using all three different Y-chromosome specific primers. The bovine satellite sequence specific primers recognize similar sequences in buffalo and are amplified both in males and in females. Similarly, Y-chromosome specific primers amplify the similar Y-chromosome specific sequences in male embryos of buffalo. Upon examining genomic DNA from lymphocytes of adult males and females, and embryos, the results demonstrate the feasibility of embryo sexing in buffaloes. Furthermore, sex determination by PCR was found to be a rapid and accurate method.     

A death certificate analysis of nasal cancer among furniture workers in North Carolina

A case-control study of nasal cancer, based on death certificate statements on occupation in North Carolina counties with furniture-manufacturing industries, revealed a 4-fold excess risk linked to this occupation. Although woodworking exposures have been associated with nasal adenocarcinomas in several areas of the world, this is the first report of such a relationship in the United States.     

Mortality and incidence of cancer among sewage workers: a retrospective cohort study

To study the incidence of and mortality from cancer among sewage workers a retrospective analysis was performed on a cohort of 656 men employed for at least one year at any one of 17 Swedish sewage plants during the years 1965-86. Assessment of exposure was done by classification of work tasks. Lower than expected total mortality (standardised mortality ratio (SMR) = 0.75, 95% confidence interval (95% CI) 0.58-0.97) and cardiovascular mortality (SMR = 0.61, 95% CI 0.39-0.91) was found. This was interpreted as a result of the healthy worker effect. For all cancers combined the mortality (SMR = 1.08, 95% CI 0.68-1.67) and morbidity (SMR = 1.02, 95% CI 0.72-1.38) were comparable with those of the general population. There were increased incidences for brain tumours (SMR = 2.19, 95% CI 0.45-6.39), gastric cancers (SMR = 2.73, 95% CI, 1.00-5.94), and renal cancers (SMR = 1.68, 95% CI = 0.35-4.90). For lung cancer the risk was reduced (SMR = 0.70, 95% CI 0.15-2.05). Allowance for a latency period of 10 years from the start of exposure did not change the pattern. Logistic modelling was used to search for exposure-response relations. In a logistic model with the confounder age forced in, renal cancer had a significant positive relation with a weighted sum of employment times, where the weights describe the classification of exposure. No exposure-response relations were found for brain tumors or gastric cancers. The increased risks are based on small numbers of cases. A future follow up will add more conclusive power to the study. Specific exposures need to be identified to allow for a better dose-response analysis.