Asbestos Burden Research Articles

Asbestos burden in lungs of mesothelioma patients with pleural plaques, lung fibrosis and/or ferruginous bodies at histology: a postmortem SEM-EDS study.

The causal attribution of asbestos-related diseases to past asbestos exposures is of crucial importance in clinical and legal contexts. Often this evaluation is made based on the history of exposure, but this method presents important limitations. To assess past asbestos exposure, pleural plaques (PP), lung fibrosis and histological evidence of ferruginous bodies (FB) can be used in combination with anamnestic data. However, such markers have never been associated with a threshold value of inhaled asbestos. With this study we attempted to shed light on the dose-response relationship of PP, lung fibrosis and FBs, investigating if their prevalence in exposed individuals who died from malignant mesothelioma (MM) is related to the concentration of asbestos in lungs assessed using scanning electron microscopy equipped with energy dispersive spectroscopy. Moreover, we estimated the values of asbestos concentration in lungs associated with PP, lung fibrosis and FB. Lung fibrosis showed a significant positive relationship with asbestos lung content, whereas PP and FB did not. We identified, for the first time, critical lung concentrations of asbestos related to the presence of PP, lung fibrosis and FB at histology (respectively, 19 800, 26 400 and 27 400 fibers per gram of dry weight), that were all well-below the background levels of asbestos identified in our laboratory. Such data suggest that PP, lung fibrosis and FB at histology should be used with caution in the causal attribution of MM to past asbestos exposures, while evaluation of amphibole lung content using analytical electron microscopy should be preferred.

A postmortem case control study of asbestos burden in lungs of malignant mesothelioma cases

BackgroundAsbestos lung content is regarded as the most reliable tool for causal attribution of malignant mesothelioma (MM) to previous asbestos exposures. However, there is a lack of studies on asbestos burden in lungs of MM patients in comparison with healthy individuals. This study aims to provide such a comparison, investigating, as well, differences in asbestos lung burden with sex and time trends.MethodsAsbestos lung content has been assessed on formalin-fixed lung fragments using scanning electron microscopy coupled with energy dispersion spectroscopy (SEM–EDS) on individuals deceased from MM (cases) and healthy subjects without any lung disease who died from violent causes (controls) between 2005 and 2023.ResultsAsbestos and asbestos bodies (ABs) were found, respectively, in 73.7% and 43.2% of cases and in 28 and 22% of controls; in MM cases the most represented asbestos types were crocidolite and amosite, whereas in controls it was tremolite-actinolite asbestos. The concentration of both asbestos fibers and ABs was statistically significantly higher in MM cases compared to controls. The mean asbestos fibers width was also significantly higher in cases than controls. Males and females with MM showed similar asbestos and ABs concentrations, but females had higher concentrations of chrysotile, and significantly lower fibers width compared to males. Time trends show that MM lung asbestos concentrations decreased starting in 2011.DiscussionThe results suggest a correlation between asbestos burden in lungs and MM risk. The different concentration of chrysotile, as well as the different width of asbestos fibers in MM males and females might reflect a sex difference in response of the lung microenvironment to inhaled asbestos. Finally, this study provides the first pathological evidence of the effect of the ban of asbestos use, demonstrating a significant decrease of asbestos lung content after 2011.

Asbestos burden in lungs of non-occupationally exposed women from Broni (Pavia, Italy): a postmortem SEM-EDS study.

In Italy the incidence of malignant mesothelioma (MM) among women is remarkably high, due to the several contexts in which women had been exposed to asbestos. However, very few studies in literature focus on the inorganic lung content in women. The aim of this retrospective, observational study is to investigate the asbestos lung burden, in terms of concentration, dimensions and type of asbestos, in 42 women who died from MM and had been non-occupationally exposed to asbestos during the activity of the asbestos-cement plant located in Broni (Pavia, Northern Italy) where mainly chrysotile, crocidolite and amosite were used. Lung samples taken during forensic autopsies have been digested using sodium hypochlorite and filtered through a cellulose-ester membrane. The filter was examined using a scanning electron microscope and the chemical composition of the fibers was analyzed using an electron dispersive spectroscopy. The number of detected inorganic fibers, asbestos fibers and asbestos bodies (ABs) were normalized to 1 gram of dry tissue. In six samples no asbestos has been detected. Overall, the most represented kind of asbestos was amosite, followed by crocidolite, tremolite/actinolite asbestos and chrysotile. The concentration of all inorganic fibers was significantly higher in women with environmental and household exposures compared with those with only environmental exposure (P=0.025), as well as the concentration of asbestos fibers (P=0.019) and ABs (P=0.049). We found a significant correlation between the concentration of asbestos fibers and the duration of exposure (rho =0.413, P=0.008), as well as with the latency of MM (rho =0.427, P=0.005). The distance of the residential address from the factory and the time spent daily in contact with asbestos did not influence the lung asbestos burden. These results suggest the relevance of the lung clearance of asbestos, regarding mainly chrysotile. As a consequence, although scanning electron microscopy -energy dispersive X-ray spectroscopy (SEM-EDS) is considered the most reliable tool for assessing previous exposure to asbestos, its results should be interpreted with caution, especially in a legal context. In addition, our data confirm the relevance of environmental and household exposure in determining asbestos concentration in lungs and highlight the importance of household exposure.

The Association between the Histological Subtypes of Mesothelioma and Asbestos Exposure Characteristics.

Asbestos mining operations have left South Africa with a legacy of asbestos contamination and asbestos-related diseases continue to be a problem. The large-scale mining of three types of asbestos presents a unique opportunity to study malignant mesothelioma of the pleura (mesothelioma) in South Africa. This study aimed to describe the demographics of deceased individuals diagnosed with mesothelioma and explore any associations between the histological morphology of mesothelioma and asbestos characteristics. We reviewed the records of all deceased miners and ex-miners from the Pathology Automation System (PATHAUT) database of the National Institute of Occupational Health (NIOH) that were histologically diagnosed with mesothelioma in the period from January 2006-December 2016 (11 years). The study population does not include all cases of mesothelioma in South Africa but rather those that reached the compensation system. Crocidolite asbestos fibres were identified in the majority of mesothelioma cases (n = 140; 53.4%). The epithelioid subtype was most commonly present in both occupational and environmental cases. Cases with the sarcomatous subtype were older at death and fewer female cases were diagnosed with this subtype. No relationship between mesothelioma subtype and asbestos type or asbestos burden or fibre size was established.

Circular economy as possible solution for asbestos burden

Asbestos has been used worldwide in a large number of products throughout the 1970 s and 1980s. After the proven influence of asbestos materials on diseases that could have a fatal outcome was confirmed, bans on the use and production of these materials began. However, there are still significant quantities of asbestos waste and materials in the environment and there is a need for safe and permanent solution. As a support to sustainable development by minimizing waste production and harmful emissions as well as by reducing the consumption of natural resources, the circular economy (CE) is recognized in the EU as a leading solution. The main meaning of CE in waste management field is to turning waste into a resource. Considering above-mentioned, this paper presents how to resolve a problem of asbestos waste that is currently and will continue to be present. Instead of occupying the space, which is also a valuable resource, with landfills that also raise cost, asbestos can be used in construction material industry. Paper presents estimated amounts of asbestos waste, proposal for appropriate waste collection, treatment and market placing of a new product in Serbia. The conclusion of the paper is that the presented model of circular economy for asbestos in Serbia is feasible, in this way it would be possible to achieve some incomes from material selling and, also, releasing some space. In addition, for the implementation of this model of asbestos management, it is necessary to have Government involvement through investment in infrastructure and improvement of legislation.

Evaluation of Deposition and Clearance of Asbestos (Detected by SEM-EDS) in Lungs of Deceased Subjects Environmentally and/or Occupationally Exposed in Broni (Pavia, Northern Italy).

Biodurability is one of the main determinants of asbestos hazardousness for human health. Very little is known about the actual persistence of asbestos in lungs and its clearance, nor about differences in this regard between the different mineralogical types of asbestos. The aim of the present study was to evaluate the amount, the dimensional characteristics and the mineralogic kinds of asbestos in lungs (measured using SEM-EDS) of a series of 72 deceased subjects who were certainly exposed to asbestos (mainly crocidolite and chrysotile) during their life. Moreover, we investigated possible correlations between the lung burden of asbestos (in general and considering each asbestos type), as well as their dimension (length, width, and l/w ratio) and the duration of exposure, the latency- in case of malignant mesothelioma (MM), the survival and the time since the end of exposure. In 62.5% of subjects, asbestos burden in lungs was lower that the threshold considered demonstrative for occupational exposure. In 29.1% of cases no asbestos was found. Chrysotile was practically not detected. The mean length of asbestos fibers and the length to width ratio were significantly related to the duration of exposure to asbestos. No other statistically significant correlations were found between the amount and dimensional characteristics of asbestos (nor with the relative amount of each asbestos type) and the other chronological variables considered. In conclusion, it was pointed out that chrysotile can be completely removed from human lungs in <8 years and, instead, amphiboles persist much more time. The present results suggest, as well, that the finding of no asbestos in lungs cannot rule out the attribution of MM to asbestos (in particular, chrysotile) inhaled in an occupational setting. This point is of crucial importance from a legal point of view.

Reply to Mirabelli et al. Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on "Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053".

We appreciate very much the interest of Mirabelli et al. [...].

Should Romanians Be Concerned with the Asbestos Burden? Research Overview and Context

"Should Romanians Be Concerned with the Asbestos Burden? Research Overview and Context. Although the negative effects of airborne asbestos fibers upon human health had been known for a long time, asbestos was widely used all over the world. Between 1980 and 2010, many countries have banned asbestos production and trade; among them, Romania banned asbestos in 2007. Romania did not extract massive amounts of asbestos; however, the country’s imports before the ban included large quantities of raw asbestos, which were later used for a wide variety of products. We have identified two peaks in the trend of raw asbestos imports, in the 1970s and the 1990s, which can be correlated to the socio-economic conditions in Romania. Lack of data availability is a real impediment to a complete estimation of the quantities of asbestos-containing products that have been used in the country. The 2007 asbestos ban did not imply the disposal of already installed such materials that could remain in place until the end of their service life. However, once removal and disposal of asbestos-containing products are needed, they come with great risks for the workers involved and the surrounding environment. Keywords: asbestos, asbestos-containing materials, health, ban, imports, production."

Characteristics of asbestos fibers in lung tissue from occupational and environmental asbestos exposure of lung cancer patients in Busan, Korea

The Asbestos Injury Relief Act in Korea requires that asbestos exposure be assessed through clinical examination and chest computed tomography (CT). However, a more specific measurement of asbestos characteristics in the lung tissue may be appropriate. We aimed to investigate the asbestos burden and characterize asbestos fibers in patients with lung cancer and ultimately assess the relationship between occupational and environmental asbestos exposure and lung cancer in Korea. We evaluated 37 lung cancer patients (LCPs) from Busan. The factors affecting asbestos burden in LCPs were analyzed using a multiple regression analysis. History of asbestos exposure (environmental/occupational), male sex, and old age were the main factors affecting asbestos burden in lung tissues of LCPs. These factors had an approximate 37% adjusted coefficient of determination. There was a significant difference in the length of asbestos fibers (4.06–37.6 µm vs. 4.26–91.7 µm) and aspect ratio (4.5–151.9 vs. 5.6–735.6) between those who were occupationally exposed to asbestos and those who were environmentally exposed (P < 0.01). Therefore, both environmental/occupational exposure to asbestos should be strongly managed to reduce the risk of lung cancer, and exposure should be assessed according to the characteristics of asbestos fibers in the lung tissue.

Relationship between pleural plaques and biomarkers of cumulative asbestos dose. A necropsy study.

Background:The relationship between pleural plaques and cumulative asbestos exposure is controversial.Objectives:To evaluate the relationship between lung asbestos bodies (AB) and fibres (AF) and plaques presence and extension.Methods:In a necropsy series of shipyard workers with asbestos-related diseases, we measured counts (per g of dry lung tissue) of AB (thousands) and AF>1 μm (millions). Pleural plaques were classified into three extension grades. We fitted univariate and multivariable linear (dependent variables: AB and AF, log10 transformed) and multinomial (dependent variable: plaques grade) regression models.Results:We analysed 124 subjects, 13 without plaques 20 with grade 1, 69 with grade 2, and 22 with grade 3 plaques. Geometric means (GM) of AB were 10.6, 23.3, 126, and 140 in the four groups respectively (P=0.0001). GMs for AF (mostly amphiboles) were 1.2, 1.4, 7.3, and 12.9 (P=0.0001). AB and AF were strongly correlated (r=0.81). The likelihood of no plaques and grade 1 plaques decreased with increasing AB and AF doses, with a corresponding increase of grade 2 and 3 plaques. Plaque presence and extension was also associated with histologically verified asbestosis (P<0.001).Conclusions:Our study showed a strong positive relationship between pleural plaque presence and extension and both lung asbestos burden and asbestosis.

Asbestos Induces Epigenetic Repression of Ras Association Domain–Containing Protein 1, p16 Kinase 4a Inhibitor, and p14 Alternative Reading Frame in Normal Human Mesothelial Cells

Rationale: Whereas asbestos burden has been linked to cytogenetic alterations in malignant pleural mesotheliomas, epigenetic aberrations induced by these fibers have not been fully delineated.Objec...

Environmental asbestos exposure sources in Korea.

BackgroundBecause of the long asbestos-related disease latencies (10–50 years), detection, diagnosis, and epidemiologic studies require asbestos exposure history. However, environmental asbestos exposure source (EAES) data are lacking.ObjectivesTo survey the available data for past EAES and supplement these data with interviews.MethodsWe constructed an EAES database using a literature review and interviews of experts, former traders, and workers. Exposure sources by time period and type were visualized using a geographic information system (ArcGIS), web-based mapping (Google Maps), and OpenWeatherMap. The data were mounted in the GIS to show the exposure source location and trend.ResultsThe majority of asbestos mines, factories, and consumption was located in Chungnam; Gyeonggi, Busan, and Gyeongnam; and Gyeonggi, Daejeon, and Busan, respectively. Shipbuilding and repair companies were mostly located in Busan and Gyeongnam.ConclusionsThese tools might help evaluate past exposure from EAES and estimate the future asbestos burden in Korea.

Asbestos-Related Burden of Disease in Latin American Countries

The aim of the study is to provide estimates of asbestos burden of disease for the Latin American countries which have been the highest asbestos consumers in the Region since 1970: Brazil, Colombia, and Mexico. Malignant diseases for which a causal association with asbestos exposure has been established are asbestosis, mesothelioma, and cancers of the lung, larynx, and ovary. For asbestosis and mesothelioma the burden of disease can be defined on the basis of the absolute number of cases, while the other neoplasms have a multifactorial etiology. For these latter, the burden of disease associated with occupational asbestos exposure can be estimated, as originally suggested by Driscoll, using the Population Attributable Fraction (PAF), on the basis of the following information: a) proportion of workforce employed in each occupational sector; b) proportion of workers exposed to asbestos in each sector; c) occupational turnover; d) levels of exposure; e) proportion of the population in the workforce; f) relative risk for each considered disease for each level of exposure. The proportion of workers exposed to asbestos in each occupational is not available for Latin American countries. For this reason, data from the European CAREX database (carcinogen exposure database) for asbestos were applied to the countries of interest with the assumption that presence of asbestos in the various occupational sectors can be similar to the one observed in Europe in the Nineties. Using mortality data of the WHO Health Statistics database for the year 2009 and applying the estimated values for PAFs, the number of estimated deaths in 5 years for mesothelioma, and for lung, larynx, and ovary cancers attributable to occupational asbestos exposures, were respectively 340, 611, 68, 43 for Brazil, 255, 97, 14, 9 for Colombia, and 1,075, 219, 18, 22 for Mexico. These figures can be improved, but are already usable to promote asbestos ban.

A study to evaluate asbestos fiber burden in lung and pleural malignancies

There is scarcity of data on asbestos fiber burden in lung and pleural malignancies. To evaluate asbestos fiber burden in biopsy samples of suspected lung and pleural malignancies. This was a single-centre, observational study. From August 2010 to July 2010. Department of Pulmonary Medicine, CSMMU, UP, Lucknow, a tertiary care hospital in India. Suspected cases of lung and pleural malignancy. Biopsy tissues taken by computed tomography (CT)-guided biopsy, bronchoscopic biopsy, and pleural biopsy by Cope's needle were analyzed for histopathology and asbestos burden by Haq et al.'s method. 20 patients were studied. Mean fiber burden was 9.25 × 10 4 fibers/g. Average burden in lung malignancies (11 patients) was 9.178 × 10 4 fibers/g and in pleural tissue (9 patients) was 9.332 × 10 4fibers/g. Among the different cell types, mean fiber burden in squamous cell carcinoma was 8.99 × 10 4 fibers/g, in adenocarcinoma was 9.71 × 10 4 fibers/g, and in small cell carcinoma was 7.54 × 10 4 fibers/g. Mean fiber burden in bronchoscopic endobronchial biopsy tissue was 10.69 × 10 4 fibers/g, while in CT-guided biopsy was 8.60× 10 4fibers/g. Maximum number of fibers was found in adenocarcinoma.

Malignant peritoneal mesothelioma: Quantitative analysis of asbestos burden

Malignant mesotheliomas develop commonly in the pleural cavity and rarely arise in the peritoneal cavity. It is well established that asbestos exposure is related to malignant pleural mesothelioma, but the asbestos burden in the abdominal cavity in patients with malignant peritoneal mesothelioma has not been well studied. The purpose of the present study was therefore to report on an autopsy case of malignant peritoneal mesothelioma with quantitative analysis of the asbestos burden in tissues from the pleura and organs in the abdominal cavity. The patient was a 67-year-old man with a history of asbestos exposure. The peritoneum was thickened with diffuse tumor proliferation. This patient was diagnosed as having malignant peritoneal epithelioid mesothelioma. The number of asbestos fibers was >10,000/g dry tissue in all samples examined except in the small intestine. The number of asbestos fibers in the stomach was 53,000/g, which was higher than that in a control asbestosis subject. The existence of numerous asbestos fibers found in the abdominal cavity suggests that asbestos stimuli are related to the tumorigenesis of malignant peritoneal mesothelioma.

Medical Insurance Aspects of Peritoneal Tumors with Particular Attention to Peritoneal Mesotheliomas

Malignant peritoneal mesotheliomas arise mainly in male patients and the median age of initial diagnosis is about 56 years. Epitheloid subtype predominates in peritoneal mesotheliomas. Asbestos exposure is the best-known and most common risk factor associated with the development of both pleural and peritoneal mesotheliomas and, therefore, about 90% of cases can be assessed as asbestos-associated. Patients with peritoneal mesotheliomas have distinctly higher asbestos burden of the lungs than patients with pleural mesotheliomas. The mean latency period between exposure and diagnosis of peritoneal mesothelioma ranges from 35 to 40 years and is comparable to that of pleural mesothelioma. Mesothelioma of the tunica vaginalis testis also belongs to the group of peritoneal mesotheliomas. No significant evidence exists for the classification of well-differentiated papillary mesothelioma, solitary fibrous tumor, adenomatoid tumor, primary peritoneal serous borderline tumor, and benign multicystic mesothelioma as asbestos-associated tumors. Except malignant mesotheliomas, the induction of other abdominal tumors is independent of an exposure to asbestos dust.

Asbestos fibers in para‐aortic and mesenteric lymph nodes

Asbestos fibers are known to accumulate in lung parenchyma and thoracic lymph nodes, but their presence and translocation into the extrapulmonary tissues need clarification. We assessed the presence of asbestos in the para-aortic (PA) and mesenteric (ME) lymph nodes. PA and ME lymph nodes and lung tissue from 17 persons who underwent medicolegal autopsy for suspicion of asbestos-related disease and from five controls were analyzed for asbestos fibers using transmission electron microscopy. High concentrations of amphibole asbestos fibers were detected in several lung tissue samples and in the respective PA and ME lymph nodes. The mean concentration for the 10 persons with a lung asbestos content of >/=1 million fibers/g of dry tissue (f/g) was 0.85 (<0.05-4.36) million f/g in the PA lymph nodes and 0.55 (<0.02-2.86) million f/g in the ME lymph nodes. The respective mean values for the 12 persons with a lung asbestos concentration of <1 million f/g were 0.07 for the PA lymph nodes and 0.03 million f/g for the ME nodes. The lung asbestos burden that predicted the detection of asbestos in abdominal lymph nodes was 0.45 million f/g. In addition to their accumulation in lung tissue, asbestos fibers also collect in the retroperitoneal and the mesenteric lymph nodes. Even low-level occupational exposure results in the presence of crocidolite, amosite, anthophyllite, tremolite, or chrysotile in these abdominal lymph nodes. Our results support the hypothesis of lymph drainage as an important translocation mechanism for asbestos in the human body.

Epigenetic Profiles Distinguish Pleural Mesothelioma from Normal Pleura and Predict Lung Asbestos Burden and Clinical Outcome

Mechanisms of action of nonmutagenic carcinogens such as asbestos remain poorly characterized. As pleural mesothelioma is known to have limited numbers of genetic mutations, we aimed to characterize the relationships among gene-locus-specific methylation alterations, disease status, asbestos burden, and survival in this rapidly fatal asbestos-associated tumor. Methylation of 1505 CpG loci associated with 803 cancer-related genes were studied in 158 pleural mesotheliomas and 18 normal pleura. After false-discovery rate correction, 969 CpG loci were independently associated with disease status (Q < 0.05). Classifying samples based on CpG methylation profile with a mixture model approach, methylation classes discriminated tumor from normal pleura (permutation P < 0.0001). In a random forests classification, the overall misclassification error rate was 3.4%, with <1% (n = 1) of tumors misclassified as normal (P < 0.0001). Among tumors, methylation class membership was significantly associated with lung tissue asbestos body burden (P < 0.03), and significantly predicted survival (likelihood ratio P < 0.01). Consistent with prior work, asbestos burden was associated with an increased risk of death (hazard ratio, 1.4; 95% confidence interval, 1.1-1.8). Our results have shown that methylation profiles powerfully differentiate diseased pleura from nontumor pleura and that asbestos burden and methylation profiles are independent predictors of mesothelioma patient survival. We have added to the growing body of evidence that cellular epigenetic dysregulation is a critical mode of action for asbestos in the induction of pleural mesothelioma. Importantly, these findings hold great promise for using epigenetic profiling in the diagnosis and prognosis of human cancers.

Asbestos Fibre Concentrations in the Lungs of Brake Workers: Another Look

To reanalyse data on the lung content of asbestos fibres among brake mechanics. I re-analysed data published by Butnor, Roggli and colleagues on the lung content of chrysotile and tremolite asbestos fibres among brake mechanics and controls. Statistics of the distributions were estimated by maximum likelihood to accommodate observations below the detection limit. Mean concentrations were compared by the t-test, bootstrap resampling and interval-censored survival methods. The mean concentrations of fibres were higher among the brake workers than the controls. The concentration of tremolite fibres was higher than the concentration of chrysotile, a pattern similar to that observed among Quebec chrysotile miners and millers. Re-analysis of published data does not support the interpretation that, in automotive brake repair workers with malignant mesothelioma, asbestos content is within the normal range. The alternative interpretation that brake mechanics have a greater than background burden of asbestos fibres, attributable to occupational exposure to dusts from friction products manufactured from Canadian chrysotile, appears more credible. This asbestos burden might be associated with an increased risk of asbestos-associated cancers.

Erfüllen Karzinoidtumoren der Lunge die Legaldefinition für den Begriff „Lungenkrebs” der Berufskrankheitenverordnung? – Untersuchungsergebnisse des Deutschen Mesotheliomregisters

Carcinoid tumours are considered to be malignant epithelial tumours according to the recent WHO classification. This study is based on the examinations of tissue from 108 patients with carcinoid tumours. Our data agree with those of other studies: carcinoid tumours developed mainly in the right lung (40 %) and the lower lobe (30 %), mean age was 56 years, typical carcinoid tumours (74 %) predominated, comparatively high proportion of females (32 %), the mean latency period after asbestos exposure - assuming asbestos as one causal factor - was 35 years. A higher incidence of carcinoid tumours (1.3 %) in the collective of the mesothelioma register compared to the incidence in the collective of all lung carcinomas (1 - 2 %) was not observed. The increased pulmonary asbestos burden analysed in 26 % of patients is explained by the exposure-dependent selection of patients in the register. So far, no association between smoking habits or exposure to other, i. e., occupational pollutions and the development of carcinoid tumours could be established. In the list of occupational diseases (No. 4104) the term "lung cancer" is used without further specification. Thus the following question remains open for discussion: does the term "lung cancer" include carcinoid tumours such as malignant epithelial lung tumours, or is it restricted to the common subtypes such as small cell carcinoma, squamous cell carcinoma, adenocarcinoma, large cell carcinoma with regard to occupational disease and compensation?