Acute myelocytic leukemia after exposure to asbestos

Asbestos exposure and haematological malignancies: a Danish cohort study

Environmental asbestos exposure and occupational asbestos exposure increase the risk of several types of cancer, but the role of such exposures for haematological malignancies remains controversial. We aimed to examine the risk of haematological malignancies: first, in subjects exposed early in life, independently of any occupational exposure occurring later; second, in subjects exposed occupationally. We established an environmentally exposed cohort from four schools located near the only former asbestos cement production plant in Denmark. We identified nearly all pupils in the seventh grade and created an age and sex-matched 1:9 reference cohort from the Danish Central Population Register. Participants were born 1940-1970 and followed up in national registers until the end of 2015. Occupational asbestos exposure was assessed for all participants using two different job exposure matrices. The school cohort included 12,111 participants (49.7% girls) and the reference cohort 108,987 participants. Eight subgroups of haematological malignancy were identified in the Danish Cancer Registry. These cases were analysed for combined overall haematological malignancy, a combined subgroup of lymphomas and a combined subgroup of leukaemias. The data were analysed using Cox regression (hazard ratios (HR)) including other cancers and death as competing risks. Haematological malignancy was identified in 1125 participants. The median follow-up was 49.3 years (0.1-63.4). Early environmental asbestos exposure was not associated with an increased risk of haematological malignancy. Long-term occupational asbestos exposure was associated with overall haematological malignancy (HR 1.69, 95% CI 1.04-2.73); in particular for the leukaemia subgroup (HR 2.14, 95% CI 1.19-3.84). This large follow-up study suggests that long-term occupational asbestos exposure is associated with increased leukaemia risk. However, further studies are needed to confirm these observations.

Review of refractory ceramic fiber (RCF) toxicity, epidemiology and occupational exposure

This literature review on refractory ceramic fibers (RCF) summarizes relevant information on manufacturing, processing, applications, occupational exposure, toxicology and epidemiology studies. Rodent toxicology studies conducted in the 1980s showed that RCF caused fibrosis, lung cancer and mesothelioma. Interpretation of these studies was difficult for various reasons (e.g. overload in chronic inhalation bioassays), but spurred the development of a comprehensive product stewardship program under EPA and later OSHA oversight. Epidemiology studies (both morbidity and mortality) were undertaken to learn more about possible health effects resulting from occupational exposure. No chronic animal bioassay studies on RCF have been conducted since the 1980s. The results of the ongoing epidemiology studies confirm that occupational exposure to RCF is associated with the development of pleural plaques and minor decrements in lung function, but no interstitial fibrosis or incremental lung cancer. Evidence supporting a finding that urinary tumors are associated with RCF exposure remains, but is weaker. One reported, but unconfirmed, mesothelioma was found in an individual with prior occupational asbestos exposure. An elevated SMR for leukemia was found, but was absent in the highly exposed group and has not been observed in studies of other mineral fibers. The industry will continue the product stewardship program including the mortality study.

Acute myeloid leukemia risk by industry and occupation

Acute myeloid leukemia (AML) is the most common type of leukemia found in adults. Identifying jobs that pose a risk for AML may be useful for identifying new risk factors. A matched case-control analysis was conducted using California Cancer Registry data from 1988 to 2007. This study included 8999 cases of AML and 24 822 controls. Industries with a statistically significant increased AML risk were construction (matched odds ratio [mOR] = 1.13); crop production (mOR = 1.41); support activities for agriculture and forestry (mOR = 2.05); and animal slaughtering and processing (mOR = 2.09). Among occupations with a statistically significant increased AML risk were miscellaneous agricultural workers (mOR = 1.76); fishers and related fishing workers (mOR = 2.02); nursing, psychiatric and home health aides (mOR = 1.65); and janitors and building cleaners (mOR = 1.54). Further investigation is needed to confirm study findings and to identify specific exposures responsible for the increased risks.

Intensity of exposure to asbestos in metropolitan Kure City as estimated by autopsied cases

In this study, the intensity of exposure to asbestos was evaluated in the residents of Kure City, the site of the Japanese naval shipyard, Kure. The number of asbestos bodies was counted in 728 autopsied cases from those treated surgically in Kure Kyosai Hospital. Five grams of lung tissue was lysed, and the number of asbestos bodies was counted with the use of light microscopic examination. By this method, the number of asbestos bodies detected in men was significantly higher than that in women. There was a peak between 60 and 70 years of age. The number of asbestos bodies in exposed cadavers in Kure City exceeded greatly that found in other districts of Japan. By this criterion, 58 of 109 patients with lung cancer had asbestos exposure, and 39 had a high exposure to asbestos. All 13 patients with malignant mesothelioma had a high exposure to asbestos. Excess asbestos exposure also was found in a large proportion of patients with gastric cancer, colon cancer, and acute leukemia. The crocidolite type of asbestos was detected frequently in patients of malignant mesothelioma or leukemia, and the chrysotile form was found in those with lung cancer.

Cancer due to asbestos exposure

To determine the relationship between malignancies and asbestos exposure, the number of asbestos bodies in wet lung tissue was counted by light microscopy according to the modified method of Smith and Naylor, and occupational histories were examined. The results revealed that 17 (89 percent) of 19 malignant mesotheliomas, 39 (38 percent) of 104 lung cancers, 23 (37 percent) of 62 gastric cancers, and 13 (28 percent) of 45 colon cancers were shown to be cases with asbestos exposure. These values were significantly higher than those of noncancerous cases (200 cases). It is of interest that five out of ten cases of leukemia were related to asbestos exposure. Nearly all multiple cancers including lung and gastric cancer in this study were also cases with asbestos exposure. Additional research should be conducted on the carcinogenicity of asbestos for multiple cancers.

Synchronous double malignancy: adenocarcinoma of lung and malignant astrocytoma induced by asbestos exposure

A 54-year-old male died of cerebellar herniation induced by brain tumor. Radiological examination of this case showed two separate tumorous lesions in the brain and lung. Autopsy proved malignant astrocytoma in the brain and coincidental alveolar cell carcinoma in the lung. He had a history of asbestos exposure for 8 years doing piping work in a shipyard. Furthermore, we detected a large number of asbestos bodies in the lung and one asbestos body in the brain. Therefore, this rare case of double cancer (malignant astrocytoma and lung cancer) might have been induced by asbestos exposure.