Occupational asbestos exposure and risk of esophageal cancer: A systematic review and meta-analysis

Esophageal cancer (EC), which includes squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), is an important cancer with poor prognosis and high mortality rate. Several occupational exposures have been associated with EC. We aim to investigate the association between occupational asbestos exposure and EC risk, considering types of asbestos and histology of the disease. We included studies mentioned in the list of references in previous reviews and pooled analyses, and we conducted an independent search in PubMed and Scopus. Forest plots of relative risks (RR) were constructed based on the association between occupational asbestos and EC risk. Random-effects models were used to address heterogeneity between 48 independent cohort and case-control studies. We found an association between occupational asbestos exposure and EC (meta-relative risk [RR] = 1.20, 95% confidence interval [CI] = 1.09-1.32; I2 = 58.8%, p-heterogeneity [het] <.001). The results of stratification by job (p-het = .20) indicate an increased RR among asbestos product workers (RR = 1.39, 95% CI = 1.07-1.81), asbestos applicators (RR = 1.41, 95% CI = 1.20-1.67), and construction workers (RR = 1.12, 95% CI = 1.02-1.24). There was no heterogeneity in meta-RR according to outcome (p = .29), geographic region (p = .69), year of publication (p = .59), quality score (p = .73), asbestos type (p = .93), study design (p = .87), and gender (p = .88), control for potential confounders (p = .20), year of first employment (p = .94) and exposure level (p = .43). The stratification analysis by histology type found an increased RR for both ESCC 1.33(1.03-1.71) and EAC 1.45(1.03-2.04) (p-het = .68). We didn't find evidence of publication bias (p = .07). The results of our study suggest that occupational asbestos exposure is associated with an increased risk of EC in both histology types.

Rapid fiber-detection technique by artificial intelligence in phase-contrast microscope images of simulated atmospheric samples

Since the manufacture, import, and use of asbestos products have been completely abolished in Japan, the main cause of asbestos emissions into the atmosphere is the demolition and removal of buildings built with asbestos-containing materials. To detect and correct asbestos emissions from inappropriate demolition and removal operations at an early stage, a rapid method to measure atmospheric asbestos fibers is required. The current rapid measurement method is a combination of short-term atmospheric sampling and phase-contrast microscopy counting. However, visual counting takes a considerable amount of time and is not sufficiently fast. Using artificial intelligence (AI) to analyze microscope images to detect fibers may greatly reduce the time required for counting. Therefore, in this study, we investigated the use of AI image analysis for detecting fibers in phase-contrast microscope images. A series of simulated atmospheric samples prepared from standard samples of amosite and chrysotile were observed using a phase-contrast microscope. Images were captured, and training datasets were created from the counting results of expert analysts. We adopted 2 types of AI models-an instance segmentation model, namely the mask region-based convolutional neural network (Mask R-CNN), and a semantic segmentation model, namely the multi-level aggregation network (MA-Net)-that were trained to detect asbestos fibers. The accuracy of fiber detection achieved with the Mask R-CNN model was 57% for recall and 46% for precision, whereas the accuracy achieved with the MA-Net model was 95% for recall and 91% for precision. Therefore, satisfactory results were obtained with the MA-Net model. The time required for fiber detection was less than 1 s per image in both AI models, which was faster than the time required for counting by an expert analyst.

A critique of Occupational Safety and Health Administration's halfmask respirator assigned protection factor

Halfmask air-purifying respirators are used by millions of workers to reduce inhaling air contaminants, both chemical (e.g., asbestos, styrene) and biological (e.g., SARS-CoV-2, Mycobacterium tuberculosis). In 2006, the federal Occupational Safety and Health Administration (OSHA) promulgated a standard that gave halfmask respirators an assigned protection factor (APF) of 10. This signified that OSHA assumes a fit-tested and trained wearer will experience a 10% maximum total inward leakage of contaminated air into the facepiece. To derive APF = 10, OSHA analyzed data from 16 workplace studies of the efficacy of halfmask respirators worn against particulate contaminants. In this commentary, I contend that, in considering the data, OSHA made several errors that overstated halfmask respirator efficacy. The errors were (i) failing to properly account for within-wearer and between-wearer variability in respirator efficacy; (ii) ignoring the effect of particle deposition in the respiratory tract; (iii) aggregating unbalanced data within and between studies, and effectively double-counting the data in some studies; and (iv) ignoring the effect that particle size exerts in penetrating respirator facepiece leak paths. The net result is that OSHA's APF = 10 can lead to excessive toxicant exposure for many workers.

Successful treatment of simultaneous malignant pleural mesothelioma and pulmonary adenocarcinoma: A case report

The present report described the case of a 74-year-old male patient with asbestos exposure whose chest computed tomography revealed a right lower lobe nodule and right pleural effusion. Pleural biopsy led to the diagnosis of epithelial malignant pleural mesothelioma (cT2N0M0, stage IB). Combination therapy with cisplatin + pemetrexed led to the complete remission of malignant pleural mesothelioma; however, the right lower lobe nodule grew in size over time. The patient was subsequently diagnosed with lung adenocarcinoma (cT1aN0M0, stage IA1) by computed tomography-guided biopsy performed 18 months after chemotherapy initiation and achieved remission of lung adenocarcinoma with stereotactic radiotherapy. The patient was alive without recurrence at the 12-month follow-up. The present case illustrated that multiple active regimens are currently available for malignant pleural mesothelioma and lung cancer that can aid in the treatment of complex cases.

Pleural mesothelioma (PMe): The evolving molecular knowledge of a rare and aggressive cancer

Mesothelioma is a type of late-onset cancer that develops in cells covering the outer surface of organs. Although it can affect the peritoneum, heart, or testicles, it mainly targets the lining of the lungs, making pleural mesothelioma (PMe) the most common and widely studied mesothelioma type. PMe is caused by exposure to fibres of asbestos, which when inhaled leads to inflammation and scarring of the pleura. Despite the ban on asbestos by most Western countries, the incidence of PMe is on the rise, also facilitated by a lack of specific symptomatology and diagnostic methods. Therapeutic options are also limited to mainly palliative care, making this disease untreatable. Here we present an overview of biological aspects underlying PMe by listing genetic and molecular mechanisms behind its onset, aggressive nature, and fast-paced progression. To this end, we report on the role of deubiquitinase BRCA1-associated protein-1 (BAP1), a tumour suppressor gene with a widely acknowledged role in the corrupted signalling and metabolism of PMe. This review aims to enhance our understanding of this devastating malignancy and propel efforts for its investigation.

The Western Australian Mesothelioma Registry: Analysis of 60 years of cases

BACKGROUND AND OBJECTIVE

Australia introduced a partial ban on asbestos consumption in 1984. There is continuing concern about exposure to asbestos in the built environment and non-occupational exposures. The aim of this study was to describe epidemiological trends of mesothelioma in Western Australia (WA) over the 60 years since the first case was recorded.

METHODS

Every case of mesothelioma notified to the WA Cancer Registry is reviewed by an expert panel. Data include demographic and clinical variables including principal mode of asbestos exposure and age at first exposure. Trends over time for survival, latency and pathological subtype of mesothelioma where analysed. Incidence rates for cases exposed during home renovation where calculated.

RESULTS

Two thousand seven hundred ninety-six cases of mesothelioma were identified with males comprising the majority (n = 2368, 84.7%). The median (IQR) age at diagnosis was 70 (62-78) years, and median latency of 47 (38-55) years. Pleural mesothelioma was recorded in 2620 (93.7%) cases with the epithelioid subtype most prevalent (n = 1730, 61.9%). Overall, median survival was 298 (128-585) days and latency 46 (37-54) years, both effectively doubling over the study period. Non-occupational exposures were proportionally higher in females (52.6%), compared with males (9.5%). Home renovation was the primary exposure in 227 (8.1%) cases, with number of cases and incidence rate ratio peaking in 2005/09 but subsequently decreasing.

CONCLUSION

The annual number of cases of mesothelioma in WA may have hit a plateau. The majority of females have non-occupational exposures and incidence rates from home renovation exposure may have peaked, suggesting the ban on asbestos has been effective.

Lung fibre burden and risk of malignant mesothelioma in shipyard workers: a necropsy-based case-control study

OBJECTIVES

In Italy, the highest pleural cancer mortality and incidence have been observed among Italian regions where the 2 largest Italian shipyards were (and are) located. The objective of this study was to assess the exposure-response relationship for mesothelioma among male workers employed in the Monfalcone, Italy, shipyard.

METHODS

We conducted a necropsy-based case-control study. Cases (N = 102) were mesothelioma decedents and controls were those with lung cancer (N = 84). Complete job histories were available; the lung fibre content was measured using a scanning electron microscope with X-ray fluorescence, after sample preparation according to the European Respiratory Society guidelines. Odds ratios and 95% confidence intervals of mesothelioma by fibre type and lung fibre burden, as a categorical or continuous variable, were assessed by unconditional logistic regression, adjusted for age and time since exposure cessation. Analyses for the amphibole and chrysotile lung fibre burden were mutually adjusted. We calculated a cumulative exposure index by applying a job-exposure matrix to the job histories of study cases and assessed its correlation with the lung fibre burden.

RESULTS

We found an odds ratio of 22.0 (confidence intervals 5.66-85.7) for the highest lung fibre burden category (mean 43.8 million total asbestos fibres per gram of dry tissue) compared with the reference (mean 0.48). Using log10-transformed lung fibre burden, we found that the odds ratio was 3.71 (confidence intervals 2.03-6.79) for a 10-fold lung fibre burden increase. Results for the amphibole lung fibre burden were similar. Odds ratios increased over chrysotile lung fibre burden categories (P-trend = 0.025), and the odds ratio for a 10-fold increase was 4.73 (confidence intervals 0.32-70.4).

CONCLUSIONS

The cumulative exposure index was correlated with total and amphibole lung fibre burden, but not with chrysotile lung fibre burden. Mesothelioma risk was proportional to total, amphibole, and chrysotile lung fibre burden in shipyard workers.

The diagnosis of asbestosis in the 21st century: a clinicopathological correlation of 102 cases

Asbestosis, defined as diffuse pulmonary fibrosis caused by inhalation of asbestos fibers, occurs after heavy exposures to asbestos dust over several decades. Because workplace exposures have been significantly curtailed since the banning of asbestos in insulation products, we were interested in examining the clinicopathological characteristics of cases diagnosed in the 21st century. The consultation files of one of the authors (VLR) were reviewed for cases of asbestosis diagnosed since 1/1/2001. 102 cases were identified, with a median age of 75 years (range: 45-89). There were 100 men and 2 women. The women were from Turkey and Brazil (none from the United States). Malignancies were present in 78 cases, including 38 lung cancers, 29 pleural mesotheliomas, and 8 peritoneal mesotheliomas. The grade of asbestosis was available in 88 cases (median severity of 2; scale: 1-4). Pleural plaque was present in 94% of cases. The most common exposure categories were insulators (39), shipyard workers (16), asbestos manufacturing (9), boiler workers (8) and pipefitter/welders (6). The median duration of exposure was 33 years (range: 2-49 years). Lung fiber burden analysis was performed in 34 cases, with amosite being the predominant fiber type. Results were compared with similar information for 475 cases diagnosed prior to 1/1/2001.

Telomere length and TERT polymorphisms as biomarkers in asbestos-related diseases

BACKGROUND

Asbestos exposure has been proposed as a risk factor for shorter telomere length. The aim of our study was to investigate whether telomere length in leukocytes and hTERT genetic polymorphisms may serve as potential biomarkers for the risk of developing asbestos-related diseases and as biomarkers of progression and chemotherapy response rate in malignant mesothelioma (MM).

SUBJECTS AND METHODS

We conducted two retrospective studies. In the first study, a case-control study, telomere length and hTERT polymorphisms were determined in patients with MM, subjects with pleural plaques and controls without the asbestos related disease, who were occupationally exposed to asbestos. In the second study, a longitudinal observational study, telomere length was also determined in samples from MM patients before and after chemotherapy. Telomere length was determined by monochromatic multiplex quantitative polymerase chain reaction (PCR), while competitive allele-specific PCR was used to genotype hTERT rs10069690, rs2736100 and rs2736098. Logistic regression and survival analysis were used in statistical analysis.

RESULTS

Patients with MM had shorter telomere length than subjects with pleural plaques (p < 0.001). After adjustment for age, rs2736098 CT, and rs10069690 TT and CT+TT genotypes were significantly associated with a higher risk of MM (padj = 0.023; padj = 0.026 and padj = 0.017), while rs2736100 AA and CA+AA genotypes conferred to a lower risk for MM compared to all other subjects (padj = 0.017, and padj = 0.026). Telomere length was not associated with a response to chemotherapy (p > 0.05) or time to disease progression (p > 0.05). Carriers of one or two polymorphic rs10069690 T alleles had a good response to chemotherapy (p = 0.039, and p = 0.048), these associations remained statistically significant after adjustment for age (padj = 0.019; padj = 0.017). Carriers of two polymorphic rs2736100 A alleles had a longer time to disease progression (p = 0.038).

CONCLUSIONS

Shorter telomere length and hTERT polymorphisms may serve as a biomarker for the risk of developing MM. Additionally, rs10069690 and rs2736100 polymorphisms, but not telomere length, were associated with a chemotherapy response or MM progression.

Spindle Cell Malignancy and Asbestos Exposure: A Case Report

We outline the presentation of a 68-year-old woman who received a chest radiograph due to her insurance requirements, resulting in the discovery of a left-sided pleural effusion. The effusion was further characterized as loculated on subsequent imaging. Thoracentesis yielded exudative fluid, leading to the patient undergoing video-assisted thoracoscopic surgery (VATS). During this procedure, a cystic mass was visualized, with the conversion of the operation to an open thoracotomy and left lower lobe lobectomy. Pathology was positive for spindle cell sarcoma. A thorough history of the patient revealed a decades-long occupational exposure to asbestos. The significance of this report is to illustrate the clinical presentation, immunohistochemical characteristics, and management of a rare spindle cell malignancy. Our case also raises the importance of screening patients on an individualized, shared decision-making basis.

Diffuse Pleural Mesothelioma: Advances in Molecular Pathogenesis, Diagnosis, and Treatment

Diffuse pleural mesothelioma (DPM) is a highly aggressive malignant neoplasm arising from the mesothelial cells lining the pleural surfaces. While DPM is a well-recognized disease linked to asbestos exposure, recent advances have expanded our understanding of molecular pathogenesis and transformed our clinical practice. This comprehensive review explores the current concepts and emerging trends in DPM, including risk factors, pathobiology, histologic subtyping, and therapeutic management, with an emphasis on a multidisciplinary approach to this complex disease.

Mortality rates from asbestos-related diseases in Italy during the first year of the COVID-19 pandemic

Background and aim

Patients with interstitial lung diseases, including asbestosis, showed high susceptibility to the SARS-CoV-2 virus and a high risk of severe COVID-19 symptoms. Italy, highly impacted by asbestos-related diseases, in 2020 was among the European countries with the highest number of COVID-19 cases. The mortality related to malignant mesotheliomas and asbestosis in 2020 and its relationship with COVID-19 in Italy are investigated.

Methods

All death certificates involving malignant mesotheliomas or asbestosis in 2010-2020 and those involving COVID-19 in 2020 were retrieved from the National Registry of Causes of Death. Annual mortality rates and rate ratios (RRs) of 2020 and 2010-2014 compared to 2015-2019 were calculated. The association between malignant pleural mesothelioma (MPM) and asbestosis with COVID-19 in deceased adults ≥80 years old was evaluated through a logistic regression analysis (odds ratios: ORs), using MPM and asbestosis deaths COVID-19-free as the reference group. The hospitalization for asbestosis in 2010-2020, based on National Hospital Discharge Database, was analyzed.

Results

In 2020, 746,343 people died; out of them, 1,348 involved MPM and 286 involved asbestosis. Compared to the period 2015-2019, the mortality involving the two diseases decreased in age groups below 80 years; meanwhile, an increasing trend was observed in subjects aged 80 years and older, with a relative mortality risks of 1.10 for MPM and 1.17 for asbestosis. In subjects aged ≥80 years, deaths with COVID-19 were less likely to have MPM in both genders (men: OR = 0.22; women: OR = 0.44), while no departure was observed for asbestosis. A decrease in hospitalization in 2020 with respect to those in 2010-2019 in all age groups, both considering asbestosis as the primary or secondary diagnosis, was observed.

Conclusions

The increasing mortality involving asbestosis and, even if of slight entity, MPM, observed in people aged over 80 years during the 1st year of the COVID-19 pandemic, aligned in part with the previous temporal trend, could be due to several factors. Although no positive association with COVID-19 mortality was observed, the decrease in hospitalizations for asbestosis among individuals aged over 80 years, coupled with the increase in deaths, highlights the importance of enhancing home-based assistance during the pandemic periods for vulnerable patients with asbestos-related conditions.

Cause specific mortality in an Italian pool of asbestos workers cohorts

BACKGROUND

Asbestos is a known human carcinogen and is causally associated with malignant mesothelioma, lung, larynx and ovarian cancers.

METHODS

Cancer risk was studied among a pool of formerly asbestos-exposed workers in Italy. Fifty-two Italian asbestos cohorts (asbestos-cement, rolling-stock, shipbuilding, and other) were pooled and their mortality follow-up was updated to 2018. Standardized mortality ratios (SMRs) were computed for major causes of death considering duration of exposure and time since first exposure (TSFE), using reference rates by region, age and calendar period.

RESULTS

The study included 63,502 subjects (57,156 men and 6346 women): 40% who were alive, 58% who died (cause known for 92%), and 2% lost to follow-up. Mortality was increased for all causes (SMR: men = 1.04, 95% confidence interval [CI] 1.03-1.05; women = 1.15, 95% CI 1.11-1.18), all malignancies (SMR: men = 1.21, 95% CI 1.18-1.23; women = 1.29, 95% CI 1.22-1.37), pleural and peritoneal malignancies (men: SMR = 10.46, 95% CI 9.86-11.09 and 4.29, 95% CI 3.66-5.00; women: SMR = 27.13, 95% CI 23.29-31.42 and 7.51, 95% CI 5.52-9.98), lung (SMR: men = 1.28, 95% CI 1.24-1.32; women = 1.26, 95% CI 1.02-1.53), and ovarian cancer (SMR = 1.42, 95% CI 1.08-1.84). Pleural cancer mortality increased during the first 40 years of TSFE (latency), reaching a plateau thereafter.

CONCLUSIONS

Analyses by time-dependent variables showed that the risk for pleural neoplasms increased with latency and no longer increases at long TSFE, consistent with with asbestos clearance from the lungs. Peritoneal neoplasm risk increased over all observation time.

Recognizing the pleura in asbestos-related pleuropulmonary disease: Known and new manifestations of pleural fibrosis

Pleural thickening (PT) is a major consequence of exposure to all fiber types of asbestos. In recent decades, it is more prevalent than parenchymal asbestosis. Its manifestations occupy a full clinical and radiographic spectrum. Six major manifestations can be identified: (a) acute pleuritis generally with effusion; (b) diffuse PT or fibrous pleuritis; (c) rounded atelectasis; (d) circumscribed PT or plaques; (e) chronic pleuritic pain; and (f) mesothelioma. Review of the experience of workers and community members in Libby, MT to asbestiform fibers in vermiculite has confirmed the appearance of these previously known benign and malignant asbestos-related diseases as well as a unique pleuropulmonary disease characterized as lamellar PT and associated with progressive decline in pulmonary function and pleuritic pain. Despite previous literature asserting that PT represents a marker for asbestos exposure without significant effect on pulmonary function and physiology, the experience of Libby amphibole (LA) disease, along with other studies, indicates that PT plays a role in declining vital capacity in those with prolonged or unusual exposures such as those arising from LA.

Occupational and Environmental Asbestos Exposure and Survival of Patients with Asbestos-Related Cancer: A Follow-Up Study on Patients with Malignant Mesothelioma and Asbestos-Related Lung Cancer in Korea

Malignant mesothelioma and asbestos-related lung cancer are typically associated with a poor prognosis. However, it has been observed that some patients with these cancers survive significantly longer than the average survival period. While many preliminary studies have investigated factors influencing patient survival, the specific impact of asbestos exposure has not been thoroughly explored. We followed up with 546 patients with malignant mesothelioma and 902 patients with asbestos-related lung cancer, all identified as asbestos victims between 2009 and 2021. In both malignant mesothelioma and asbestos-related lung cancer, patients with occupational asbestos exposure exhibited not only shorter median survival times but also lower 3- and 5-year survival rates compared to those with environmental exposure. Additionally, a longer duration of occupational exposure and closer proximity to the source of asbestos were linked to shorter survival times and lower survival rates. Among the patients with occupational asbestos exposure, the highest hazard ratios (HRs) were observed in those who worked in the production of asbestos-containing products across both cancer types. In contrast, significant HRs were only noted in mesothelioma patients who lived near asbestos industries, slate houses, and redevelopment areas, within the environmentally exposed group.

Tasks and Experiences of the Prospective, Longitudinal, Multicenter MoMar (Molecular Markers) Study for the Early Detection of Mesothelioma in Individuals Formerly Exposed to Asbestos Using Liquid Biopsies

Mesothelioma is an aggressive cancer, strongly associated with prior exposure to asbestos. Commonly, tumors are detected at late stages of the disease. Detection at early stages might be meaningful, because therapies might be more effective when the tumor burden is relatively low and the tumor has not spread to distant sites. Circulating biomarkers in blood might be a promising tool to improve the early detection of mesothelioma, but for screening in asymptomatic subjects, candidate biomarkers need to be validated in appropriate studies. This study was conducted to assess the performance of biomarkers in liquid biopsies to detect mesothelioma at early stages. Over a period of 10 years, 2769 volunteers formerly exposed to asbestos were annually examined and liquid biopsies were collected. A follow-up was completed 17 months after the last blood collection. The article provides a detailed overview of our lessons learned and experiences of conducting a prospective, longitudinal, multicenter study. The existing cohort of individuals at risk is highly suitable for the validation of blood-based biomarkers for the early detection of mesothelioma as well as lung cancer.

The Current Treatment Landscape of Malignant Pleural Mesothelioma and Future Directions

The incidence of malignant pleural mesothelioma is expected to increase globally. New treatment options for this malignancy are eagerly awaited to improve the survival and quality of life of patients. The present article highlights the results of recent advances in this field, analyzing data from several relevant trials. The heterogeneous tumor microenvironment and biology, together with the low mutational burden, pose a challenge for treating such tumors. So far, no single biomarker has been soundly correlated with targeted therapy development; thus, combination strategies are often required to improve outcomes. Locally applied vaccines, the expansion of genetically engineered immune cell populations such as T cells, the blockage of immune checkpoints that inhibit anti-tumorigenic responses and chemoimmunotherapy are among the most promising options expected to change the mesothelioma treatment landscape.

[Malignant mesothelioma in Colombia: burden of disease, overview, and subnational sociodemographic index, 2015-2020Mesotelioma maligno na Colômbia: carga de morbidade, visão geral e índice sociodemográfico subnacional, entre 2015 e 2020]

Objective

Establish the disease burden of malignant mesothelioma (MM) in Colombia between 2015 and 2020, and its association with the subnational sociodemographic development index (SDI) and with asbestos sites.

Methods

Mixed ecological study of the Colombian population diagnosed with MM (according to ICD-10) from 2015 to 2020. The global burden of disease (GBD) was estimated using the methodology proposed by Murray and Lopez, based on prevalence and mortality data obtained from official sources. The subnational (departmental level) SDI was estimated as a measure of socioeconomic development. Linear regressions were established with the GBD, SDI, and documented asbestos sites.

Results

The estimated GBD of MM in Colombia during 2015-2020 was 51.71 disability-adjusted life years (DALYs) per 1 000 000 inhabitants (15 375.79 total DALYs), with predominance in people over 50 years of age (91.1%) and males (66.4%).Bogotá and Valle del Cauca were the departments with the highest number of adjusted DALYs. Bogotá had the highest SDI and Guainía and Cesar had the lowest. There was evidence of an association between DALYs and SDI, explaining 22.8% of DALYs.

Conclusion

Malignant mesothelioma is the cause of a large number of DALYs, predominantly in the departments with greater socioeconomic development and with companies that used to use asbestos. However, possible underdiagnosis of MM limits analysis of the information.

Case Report: Early diagnosis and bevacizumab-based chemotherapy for primary pericardial mesothelioma: a case with occupational asbestos exposure history

Background

Primary pericardial mesothelioma (PPM) is an exceedingly rare malignant cancer and has a poor prognosis, which has been partly attributed to its frequently delayed diagnosis due to its nonspecific syndromes, its similar presentation to benign pericardial diseases, and its non-definitive etiology. In many PPM cases, the time from presentation to definite diagnosis may last for several months or even over one year. Unlike pleural mesothelioma, the relationship between PPM and asbestos exposure remains unsettled. To date, there is no consensus on the treatment of PPM.

Case report

The patient is a 57-year-old male who had nonspecific syndromes and inconclusive image findings. The occupational long-term asbestos exposure history of this patient raised our concerns regarding potential malignancy when confronted with unexplained pericardial effusion accompanied by cardiac tamponade. The heightened suspicion prompted us to perform pericardiocentesis and biopsy on the third day after admission to our department. An early diagnosis of PPM was established by the pathological and immunohistochemical evaluation of the biopsy specimen two weeks after admission. Positron emission tomography-computed tomography revealed that the lesion was localized at the anterior part of the mediastinum without distant metastasis. This patient refused to receive cardiac surgery. He subsequently underwent six cycles of chemotherapy (cisplatin plus pemetrexed) in combination with bevacizumab (a humanized anti-VEGF antibody) as the first-line treatment, resulting in complete relief of symptoms and satisfactory outcomes with no complications. Four months after the first course, the patient initiated a second course of chemotherapy with a similar regimen, but he opted to discontinue the medical treatment after the initiation of the second course. The patient was transferred to the hospice care unit and unfortunately expired one year after the initial presentation.

Conclusion

We present a case of an early multidisciplinary clinical approach to diagnose and manage PPM with consideration of occupational asbestos exposure history and clinical symptoms. Bevacizumab-based chemotherapy remains an option for the treatment of PPM.

Dissolution Reaction and Surface Modification of UICC Amosite in Mimicked Gamble's Solution: A Step towards Filling the Gap between Asbestos Toxicity and Its Crystal Chemical Features

This study focuses on the dissolution process and surface characterization of amosite fibres following interaction with a mimicked Gamble's solution at a pH of 4.5 and T = 37 °C, up to 720 h. To achieve this, a multi-analytical approach was adopted, and the results were compared to those previously obtained on a sample of asbestos tremolite and UICC crocidolite, which were investigated under the same experimental conditions. Combining surface chemical data obtained by XPS with cation release quantified by ICP-OES, an incongruent behaviour of the fibre dissolution was highlighted for amosite fibres, similarly to asbestos tremolite and UICC crocidolite. In particular, a preferential release of Mg and Ca from the amphibole structure was observed, in agreement with their Madelung site energies. Notably, no Fe release from amosite fibres was detected in our experimental conditions (pH of 4.5 and atmospheric pO2), despite the occurrence of Fe(II) at the M(4) site of the amphibole structure, where cations are expected to be rapidly leached out during mineral dissolution. Moreover, the oxidation of both the Fe centres initially present on the fibre surface and those promoted from the bulk, because of the erosion of the outmost layers, was observed. Since biodurability (i.e., the resistance to dissolution) is one of the most important toxicity parameters, the knowledge of the surface alteration of asbestos possibly occurring in vivo may help to understand the mechanisms at the basis of its long-term toxicity.

Malignant pleural mesothelioma with resolution of pleural effusion

In malignant pleural mesothelioma patients, pleural effusion may improve during the course of the disease. Pleural effusion with nodular shadows bordering the pleura should be followed up even if the pleural effusion improves.

Mesothelioma Risk Among Maritime Workers According to Job Title: Data From the Italian Mesothelioma Register (ReNaM)

The study describes the 466 cases of malignant mesotheliomas (MM) collected by the National Mesothelioma Register (ReNaM) in Italy in the period 1993-2018 relating to subjects with exclusive asbestos exposure in merchant or military navy. The cases among maritime workers represent 1.8% of the total cases with defined exposure registred in the ReNaM, of which 212 cases (45.4%) among merchant maritime workers and 254 cases (54.5%) among navy. The distribution by site of mesothelioma showed 453 (97.2%) MM cases of the pleura, 11 (2.3%) of the peritoneum and 2 (0.4%) of the tunica vaginalis of the testis. With regard to occupational exposure, it was classified as certain in 318 (68.2%) cases, probable in 69 (14.8%) cases and possible in 79 (16.9%) cases. Among the 23 classified jobs, the highest percentages of certain exposures are among naval engineers, motor mechanics, machine captains and sailors. Machine crew accounted for 49.3% of the cases, deck crew for 27.6%. All cases began exposure on board between 1926 and 1988. Seamen were exposed to asbestos while at sea by virtue of living onboard ships and from continual release of asbestos fibers due to the motion of a vessel. Epidemiological surveillance through the ReNaM has allowed us to verify among cases in the maritime, navy and merchant marine sectors, that in the past, subjects were exposed regardless of the ship's department where have provided service therefore all these cases must be considered as occupational diseases.

The role of single nucleotide polymorphisms related to iron homeostasis in mesothelioma susceptibility after asbestos exposure: a genetic study on autoptic samples

Asbestos-related diseases still represent a major public health problem all over the world. Among them, malignant mesothelioma (MM) is a poor-prognosis cancer, arising from the serosal lining of the pleura, pericardium and peritoneum, triggered by asbestos exposure. Literature data suggest the key role of iron metabolism in the coating process leading to the formation of asbestos bodies, considered to be both protective and harmful. Two sample sets of individuals were taken into consideration, both residing in Broni or neighboring cities (Northwestern Italy) where an asbestos cement factory was active between 1932 and 1993. The present study aims to compare the frequency of six SNPs involved in iron trafficking, previously found to be related to protection/predisposition to MM after asbestos exposure, between 48 male subjects with documented asbestos exposure who died of MM and 48 male subjects who were exposed to asbestos but did not develop MM or other neoplastic respiratory diseases (Non-Mesothelioma Asbestos Exposed - NMAE). The same analysis was performed on 76 healthy male controls. The allelic and genotypic frequencies of a sub-group of 107 healthy Italian individuals contained in the 1000 genomes database were considered for comparison. PCR-multiplex amplification followed by SNaPshot mini-sequencing reaction was used. The findings presented in this study show that the allelic and genotypic frequencies for six SNP markers involved in iron metabolism/homeostasis and the modulation of tumor microenvironment are not significantly different between the two sample sets of MM and NMAE. Therefore, the SNPs here considered do not seem to be useful markers for individual susceptibility to mesothelioma. This finding is not in agreement with previous literature.

Characteristics of transcription profile, adhesion and migration of SETD2-loss Met-5A mesothelial cells exposed with crocidolite

Asbestos is a fibrous silicate mineral exhibiting biopersistence and carcinogenic properties and contributes to mesothelioma. Despite the concept of gene-environmental interaction in pathogenesis of mesothelioma, the possible pathophysiological changes of mesothelial cells simultaneously with SET domain containing 2 (SETD2) loss and asbestos exposure remains obscure. Herein, CRISPR/Cas9-mediated SETD2 knockout Met-5A mesothelial cells (Met-5ASETD2-KO ) were established and exposed with crocidolite, an amphibole asbestos. Cell viability of Met-5ASETD2-KO appeared to dramatically decrease with ≥2.5 μg/cm2 crocidolite exposure as compared with Met-5A, although no cytotoxicity and apoptosis changes of Met-5ASETD2-KO and Met-5A was evident with 1.25 μg/cm2 crocidolite exposure for 48 h. RNA sequencing uncovered top 50 differentially expressed genes (DEGs) between 1.25 μg/cm2 crocidolite exposed Met-5ASETD2-KO (Cro-Met-5ASETD2-KO ) and 1.25 μg/cm2 crocidolite exposed Met-5A (Cro-Met-5A), and ITGA4, THBS2, MYL7, RAC2, CADM1, and CLDN11 appeared to be the primary DEGs involved with adhesion in gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Cro-Met-5ASETD2-KO had strong migration but mild adhesion behavior as compared with Cro-Met-5A. Additionally, crocidolite tended to increase migration of Met-5ASETD2-KO but inhibited migration of Met-5A when compared with their corresponding cells without crocidolite exposure, although no further adhesion property changes was evident for both cells in response to crocidolite. Therefore, crocidolite may affect adhesion-related gene expression and modify adhesion and migration behavior for SETD2-depleted Met-5A, which could provide preliminary insight regarding the potential role of SETD2 in the cell behavior of asbestos-related malignant mesothelial cell.

HMGB1 released by mesothelial cells drives the development of asbestos-induced mesothelioma

Asbestos is the main cause of malignant mesothelioma. Previous studies have linked asbestos-induced mesothelioma to the release of HMGB1 from the nucleus to the cytoplasm, and from the cytoplasm to the extracellular space. In the cytoplasm, HMGB1 induces autophagy impairing asbestos-induced cell death. Extracellularly, HMGB1 stimulates the secretion of TNFα. Jointly, these two cytokines kick-start a chronic inflammatory process that over time promotes mesothelioma development. Whether the main source of extracellular HMGB1 were the mesothelial cells, the inflammatory cells, or both was unsolved. This information is critical to identify the targets and design preventive/therapeutic strategies to interfere with asbestos-induced mesothelioma. To address this issue, we developed the conditional mesothelial HMGB1-knockout (Hmgb1ΔpMeso) and the conditional myelomonocytic-lineage HMGB1-knockout (Hmgb1ΔMylc) mouse models. We establish here that HMGB1 is mainly produced and released by the mesothelial cells during the early phases of inflammation following asbestos exposure. The release of HMGB1 from mesothelial cells leads to atypical mesothelial hyperplasia, and in some animals, this evolves over the years into mesothelioma. We found that Hmgb1ΔpMeso, whose mesothelial cells cannot produce HMGB1, show a greatly reduced inflammatory response to asbestos, and their mesothelial cells express and secrete significantly reduced levels of TNFα. Moreover, the tissue microenvironment in areas of asbestos deposits displays an increased fraction of M1-polarized macrophages compared to M2 macrophages. Supporting the biological significance of these findings, Hmgb1ΔpMeso mice showed a delayed and reduced incidence of mesothelioma and an increased mesothelioma-specific survival. Altogether, our study provides a biological explanation for HMGB1 as a driver of asbestos-induced mesothelioma.

Determining the clinical utility of a breath test for screening an asbestos-exposed population for pleural mesothelioma: baseline results

Pleural mesothelioma (PM) is an aggressive cancer of the serosal lining of the thoracic cavity, predominantly caused by asbestos exposure. Due to nonspecific symptoms, PM is characterized by an advanced-stage diagnosis, resulting in a dismal prognosis. However, early diagnosis improves patient outcome. Currently, no diagnostic biomarkers or screening tools are available. Therefore, exhaled breath was explored as this can easily be obtained and contains volatile organic compounds, which are considered biomarkers for multiple (patho)physiological processes. A breath test, which differentiates asbestos-exposed (AEx) individuals from PM patients with 87% accuracy, was developed. However, before being implemented as a screening tool, the clinical utility of the test must be determined. Occupational AEx individuals underwent annual breath tests using multicapillary column/ion mobility spectrometry. A baseline breath test was taken and their individual risk of PM was estimated. PM patients were included as controls. In total, 112 AEx individuals and six PM patients were included in the first of four screening rounds. All six PM patients were correctly classified as having mesothelioma (100% sensitivity) and out of 112 AEx individuals 78 were classified by the breath-based model as PM patients (30% specificity). Given the large false positive outcome, the breath test will be repeated annually for three more consecutive years to adhere to the 'test, re-test' principle and improve the false positivity rate. A low-dose computed tomography scan in those with two consecutive positive tests will correlate test positives with radiological findings and the possible growth of a pleural tumor. Finally, the evaluation of the clinical value of a breath-based prediction model may lead to the initiation of a screening program for early detection of PM in Aex individuals, which is currently lacking. This clinical study received approval from the Antwerp University Hospital Ethics Committee (B300201837007).

Measurements of airborne asbestos fibres during refurbishing

Although the use of asbestos fibres in building materials has been prohibited in Norway since 1985, asbestos-containing materials (ACMs) are still found in many buildings. Lack of knowledge and awareness of these materials may lead to exposure during refurbishing. The aim of this study was to investigate the airborne fibre concentration and classify fibres found during the abatement of various ACMs. The release of fibres during short-term work tasks, such as drilling and sawing, was also investigated. Parallel air samples were collected during asbestos abetment of different building materials and analysed with scanning electron microscope (SEM) and phase-contrast microscope (PCM), respectively. Material samples were analysed with SEM. A real-time fibre monitor was used to measure asbestos during short-term work. The highest fibre concentrations were measured for samples collected during the removal of asbestos insulating boards (1.5-4.5 fibres/cm3 [f/cm3]), and the numbers were relatively similar for SEM and PCM. A large difference in asbestos concentrations was found between SEM and PCM when analysing floor materials, which were probably caused by a high number of gypsum fibres that the PCM operator counted. Thin fibres (<0.2 µm in width) were included in the SEM count and constituted up to 50% of the total fibre concentration for the asbestos cement materials. The presence of other inorganic and organic fibres on these samples probably led to similar results between SEM and PCM. Short-term work led to peak concentrations above 30 f/cm3.

Recurrent Tumor Suppressor Alterations in Primary Pericardial Mesothelioma

Primary pericardial mesotheliomas are extremely rare, accounting for <1% of all mesotheliomas, and their molecular genetic features and predisposing factors remain to be determined. Here, we report the clinicopathologic, immunohistochemical, and molecular genetic findings of 3 pericardial mesotheliomas without pleural involvement. Three cases diagnosed between 2004 and 2022 were included in the study and analyzed by immunohistochemistry and targeted next-generation sequencing (NGS); corresponding nonneoplastic tissue was sequenced in all cases. Two patients were female and 1 was male, aged between 66 and 75 years. Two patients each had prior asbestos exposure and were smokers. Histologic subtypes were epithelioid in 2 cases and biphasic in 1 case. Immunohistochemical staining identified expression of cytokeratin AE1/AE3 and calretinin in all cases, D2-40 in 2 cases, and WT1 in 1 case. Staining for tumor suppressors revealed loss of p16, MTAP, and Merlin (NF2) expression in 2 cases and loss of BAP1 and p53 in 1 case. Abnormal cytoplasmic BAP1 expression was observed in an additional case. Protein expression abnormalities correlated with NGS results, which showed concurrent complete genomic inactivation of CDKN2A/p16, CDKN2B, MTAP, and NF2 in 2 mesotheliomas and of BAP1 and TP53 in 1 mesothelioma each, respectively. In addition, 1 patient harbored a pathogenic BRCA1 germline mutation, which resulted in biallelic inactivation in the mesothelioma. All mesotheliomas were mismatch repair proficient and showed several chromosomal gains and losses. All patients died from disease. Our study demonstrates that pericardial mesotheliomas share common morphologic, immunohistochemical, and molecular genetic features with pleural mesothelioma, including recurrent genomic inactivation of canonical tumor suppressors. Our study adds new insights into the genetic landscape of primary pericardial mesothelioma and highlights BRCA1 loss as a potential contributing factor in a subset of cases, thereby contributing to refined precision diagnostics for this rare cancer.

Managing the risks of an asbestos bulk storage facility at a research institute

The South African National Institute for Occupational Health (NIOH), formerly the Pneumoconiosis Research Unit, has previously milled about 544 kg of anthophyllite, crocidolite, amosite and chrysotile asbestos fibre materials. This endeavour came about in an attempt to address a recommendation, made by the International Union Against Cancer (UICC), to make asbestos standard reference samples available for research. Some of these reference samples, as well as the bulk, unprocessed materials are still within the care of the NIOH and can be obtained for the purpose of Public Health research under strict terms and conditions. Considering the hazardous nature of asbestos and regulated prohibitions imposed on this mineral, the NIOH asbestos storage facility is being subjected to various occupational and environmental control measures to ensure that any potential fibre release, and subsequent risk of exposure, are prevented.

APE-1/Ref-1 Inhibition Blocks Malignant Pleural Mesothelioma Cell Proliferation and Migration: Crosstalk between Oxidative Stress and Epithelial Mesenchymal Transition (EMT) in Driving Carcinogenesis and Metastasis

Malignant pleural mesothelioma (MPM) is an aggressive cancer associated with asbestos exposure. MPM pathogenesis has been related both to oxidative stress, evoked by and in response to asbestos fibers exposure, and epithelial mesenchymal transition (EMT), an event induced by oxidative stress itself and related to cancer proliferation and metastasis. Asbestos-related primary oxidative damage is counteracted in the lungs by various redox-sensitive factors, often hyperactivated in some cancers. Among these redox-sensitive factors, Apurinic-apyrimidinic endonuclease 1 (APE-1)/Redox effector factor 1 (Ref-1) has been demonstrated to be overexpressed in MPM and lung cancer, but the molecular mechanism has not yet been fully understood. Moreover, asbestos exposure has been associated with induced EMT events, via some EMT transcription factors, such as Twist, Zeb-1 and Snail-1, in possible crosstalk with oxidative stress and inflammation events. To demonstrate this hypothesis, we inhibited/silenced Ref-1 in MPM cells; as a consequence, both EMT (Twist, Zeb-1 and Snail-1) markers and cellular migration/proliferation were significantly inhibited. Taken as a whole, these results show, for the first time, crosstalk between oxidative stress and EMT in MPM carcinogenesis and invasiveness, thus improving the knowledge to better address a preventive and therapeutic approach against this aggressive cancer.

Exposure to insulating materials and risk of coronary artery diseases: a cross-sectional study

Background

Although previous reports link exposure to insulating materials with an increased risk of mesothelioma and chronic respiratory diseases, studies evaluating their associations with the risk of coronary artery diseases (CAD) are lacking.

Aims

We aimed at evaluating the associations between exposure to insulating materials and the 10-year risk of CAD among insulators.

Methods

In this cross-sectional study, we recruited 643 adults (≥18 years), full-time insulators from the Local 110 Heat and Frost Insulators and Allied Workers Union in Edmonton, Alberta. We obtained demographic information, personal and family history, and job-exposure history, including experience (years) and types of exposure to insulating materials. Clinical profiling including Framingham risk scores (FRS) was assessed.

Results

Of all insulators, 89% were men (mean ± SD age: 47 ± 12 years), 27% had a parental history of cardiac diseases, and 22% had a comorbid chronic respiratory disease. In total, 53% reported exposure to asbestos, while 61, 82, and 94% reported exposure to ceramic fibers, fiberglass, and mineral fibers, respectively. In single-exposure multivariable regression models adjusted for experience, marital status, and body mass index (BMI), asbestos was found to be associated with higher FRS (β: 1.004; 95%CI: 0.003-2.00). The association remained consistent in multi-exposure models and a higher association was found between asbestos exposure and FRS among insulators with comorbid chronic respiratory disease.

Conclusion

Our study demonstrates that apart from cancer and chronic respiratory diseases, asbestos exposure may also have a cardiac effect, thus warranting the need for systematic surveillance to protect workers from the adverse effects of these materials.

Asbestos and Iron

Theories of disease pathogenesis following asbestos exposure have focused on the participation of iron. After exposure, an open network of negatively charged functional groups on the fiber surface complexes host metals with a preference for iron. Competition for iron between the host and the asbestos results in a functional metal deficiency. The homeostasis of iron in the host is modified by the cell response, including increased import to correct the loss of the metal to the fiber surface. The biological effects of asbestos develop in response to and are associated with the disruption of iron homeostasis. Cell iron deficiency in the host following fiber exposure activates kinases and transcription factors, which are associated with the release of mediators coordinating both inflammatory and fibrotic responses. Relative to serpentine chrysotile, the clearance of amphiboles is incomplete, resulting in translocation to the mesothelial surface of the pleura. Since the biological effect of asbestos is dependent on retention of the fiber, the sequestration of iron by the surface, and functional iron deficiency in the cell, the greater clearance (i.e., decreased persistence) of chrysotile results in its diminished impact. An inability to clear asbestos from the lower respiratory tract initiates a host process of iron biomineralization (i.e., asbestos body formation). Host cells attempt to mobilize the metal sequestered by the fiber surface by producing superoxide at the phagosome membrane. The subsequent ferrous cation is oxidized and undergoes hydrolysis, creating poorly crystalline iron oxyhydroxide (i.e., ferrihydrite) included in the coat of the asbestos body.

Malignant Peritoneal Mesothelioma: A Case Report

Malignant peritoneal mesothelioma (MPM) is a rare tumor of the serous membranes of the peritoneum and has been linked to exposure to asbestos and other risk factors. The clinical manifestations are vague, with a wide clinical spectrum, predominantly related to the abdominal involvement of the disease. Localized mesothelioma is an uncommon manifestation of the disease. Common symptoms include abdominal pain or abdominal distention, nausea, anorexia, and weight loss. Rarely, patients present with paraneoplastic syndrome. Due to the nonspecific symptoms, many patients already have advanced disease at the time of diagnosis. The authors report a case of a 75-year-old female patient who presented with symptoms of asthenia, anorexia, progressive paleness, and weight loss lasting five months. She reports later new-onset symptoms of diffuse abdominal pain and diarrhea associated with nausea. Laboratory tests showed anemia, mild leukocytosis, thrombocytosis, elevated C-reactive protein (CRP), and elevated liver enzymes. An abdominal and pelvic computed tomography (CT) scan revealed marked tissue thickening of an irregular and striated configuration of the leaflets and peritoneal reflections in an omental cake pattern, and a chest CT scan showed multiple bilateral pulmonary nodules, suggesting diffuse malignant disease. A CT-guided biopsy of a peritoneal implant was performed, establishing the diagnosis of malignant peritoneal mesothelioma. Due to rapid clinical deterioration, the patient did not receive any systemic treatment, surgery, or radiotherapy and was transitioned to comfort care. As in the presented case, most cases of MPM have diffuse peritoneal involvement at the time of diagnosis, although extra-abdominal involvement is very rare. This disease presentation is associated with high morbidity and mortality compared to cases of localized disease. There is no specific imaging diagnostic modality or valuable tumor markers for MPM. Although a CT scan remains important in the diagnostic approach, the changes found are not specific. Radiographically, MPM may present as mesenteric or parietal peritoneal nodules, visceral peritoneal thickening, ascites, or omental masses. Although these features may raise suspicion of MPM, a biopsy is necessary to confirm the diagnosis. Therefore, due to the rarity of this disease and its nonspecific signs or symptoms, MPM is difficult to diagnose, and the prognosis remains poor.

Malignant mesothelioma tumours: molecular pathogenesis, diagnosis, and therapies accompanying clinical studies

The pathetic malignant mesothelioma (MM) is a extremely uncommon and confrontational tumor that evolves in the mesothelium layer of the pleural cavities (inner lining- visceral pleura and outer lining- parietal pleura), peritoneum, pericardium, and tunica vaginalis and is highly resistant to standard treatments. In mesothelioma, the predominant pattern of lesions is a loss of genes that limit tumour growth. Despite the worldwide ban on the manufacture and supply of asbestos, the prevalence of mesothelioma continues to increase. Mesothelioma presents and behaves in a variety of ways, making diagnosis challenging. Most treatments available today for MM are ineffective, and the median life expectancy is between 10 and 12 months. However, in recent years, considerable progress has already been made in understanding the genetics and molecular pathophysiology of mesothelioma by addressing hippo signaling pathway. The development and progression of MM are related to many important genetic alterations. This is related to NF2 and/or LATS2 mutations that activate the transcriptional coactivator YAP. The X-rays, CT scans, MRIs, and PET scans are used to diagnose the MM. The MM are treated with surgery, chemotherapy, first-line combination chemotherapy, second-line treatment, radiation therapy, adoptive T-cell treatment, targeted therapy, and cancer vaccines. Recent clinical trials investigating the function of surgery have led to the development of innovative approaches to the treatment of associated pleural effusions as well as the introduction of targeted medications. An interdisciplinary collaborative approach is needed for the effective care of persons who have mesothelioma because of the rising intricacy of mesothelioma treatment. This article highlights the key findings in the molecular pathogenesis of mesothelioma, diagnosis with special emphasis on the management of mesothelioma.

Global, Regional, and National Burden of Mesothelioma 1990-2019: A Systematic Analysis of the Global Burden of Disease Study 2019

Rationale: Mesothelioma has become a major health burden since World War II because of the use of asbestos. Although many countries have imposed bans on asbestos, there remain significant mortality and morbidity from mesothelioma because of its long latent period and aggressiveness. Also, the use of asbestos is increasing in low-income countries, potentiating risk of mesothelioma in the coming decades. Assessment of the global burden of mesothelioma is required to take proper measures against the disease. Objectives: To assess the burden of mesothelioma from 1990 to 2019 at the global, regional, and national levels and to investigate patterns according to sex, age, sociodemographic index, and risk factors. Methods: The numbers, rates, and age-standardized rates of incidence, death, and disability-adjusted life years (DALYs) of mesothelioma in 204 countries and territories from 1990 to 2019 were estimated using vital registration and cancer registry data. The relationship between sociodemographic index and age-standardized DALY rate was determined, and DALYs attributable to occupational exposure to asbestos were calculated. Results: In 2019, there were 34,511 (95% uncertainty interval [UI], 31,199 to 37,771) incident cases of mesothelioma globally, with an age-standardized rate of 0.43 per 100,000 persons (95% UI, 0.38 to 0.47), which decreased between 1990 and 2019 by -12.6% (95% UI, -21.8% to -2.3%). Mesothelioma was responsible for 29,251 (95% UI, 26,668 to 31,006) deaths in 2019, with an age-standardized rate of 0.36 deaths per 100,000 persons (95% UI, 0.33 to 0.39), which decreased between 1990 and 2019 by -9.6% (95% UI, -17.8% to -1.1%). The age-standardized incidence rate increased in central Europe between 1990 and 2019 by 46.1% (95% UI, 16.6% to 72.4%). The Netherlands, Australia, and the United Kingdom had the highest age-standardized incidence rates. Incidence rates were higher in men than in women ages 45-49 to 90-94 years, peaking at 85-89 years. Occupational exposure to asbestos contributed to 85.2% (95% UI, 82.1% to 88.1%) of DALYs. Conclusions: The global burden of mesothelioma is decreasing in terms of age-standardized incidence and mortality rates. Mesothelioma remains a substantial public health challenge in many parts of the world.

The crystal structure of the killer fibre erionite from Tuzköy (Cappadocia, Turkey)

Erionite is a non-asbestos fibrous zeolite classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen and is considered today similar to or even more carcinogenic than the six regulated asbestos minerals. Exposure to fibrous erionite has been unequivocally linked to cases of malignant mesothelioma (MM) and this killer fibre is assumed to be directly responsible for more than 50% of all deaths in the population of the villages of Karain and Tuzköy in central Anatolia (Turkey). Erionite usually occurs in bundles of thin fibres and very rarely as single acicular or needle-like fibres. For this reason, a crystal structure of this fibre has not been attempted to date although an accurate characterization of its crystal structure is of paramount importance for our understanding of the toxicity and carcinogenicity. In this work, we report on a combined approach of microscopic (SEM, TEM, electron diffraction), spectroscopic (micro-Raman) and chemical techniques with synchrotron nano-single-crystal diffraction that allowed us to obtain the first reliable ab initio crystal structure of this killer zeolite. The refined structure showed regular T-O distances (in the range 1.61-1.65 Å) and extra-framework content in line with the chemical formula (K_2.63Ca₁.₅₇Mg_0.76Na_0.13Ba_0.01)[Si_28.62Al_7.35]O₇₂·28.3H₂O. The synchrotron nano-diffraction data combined with three-dimensional electron diffraction (3DED) allowed us to unequivocally rule out the presence of offretite. These results are of paramount importance for understanding the mechanisms by which erionite induces toxic damage and for confirming the physical similarities with asbestos fibres.

Asbestos accelerates disease onset in a genetic model of malignant pleural mesothelioma

Hypothesis: Asbestos-driven inflammation contributes to malignant pleural mesothelioma beyond the acquisition of rate-limiting mutations. Methods: Genetically modified conditional allelic mice that were previously shown to develop mesothelioma in the absence of exposure to asbestos were induced with lentiviral vector expressing Cre recombinase with and without intrapleural injection of amosite asbestos and monitored until symptoms required euthanasia. Resulting tumours were examined histologically and by immunohistochemistry for expression of lineage markers and immune cell infiltration. Results: Injection of asbestos dramatically accelerated disease onset and end-stage tumour burden. Tumours developed in the presence of asbestos showed increased macrophage infiltration. Pharmacological suppression of macrophages in mice with established tumours failed to extend survival or to enhance response to chemotherapy. Conclusion: Asbestos-driven inflammation contributes to the severity of mesothelioma beyond the acquisition of rate-limiting mutations, however, targeted suppression of macrophages in established epithelioid mesothelioma showed no therapeutic benefit.

The Epidemiological Surveillance of Mesothelioma Mortality in Italy as a Tool for the Prevention of Asbestos Exposure

As part of a surveillance plan active since the early 1990s, this study evaluates malignant mesothelioma (MM) mortality for the time-window 2010-2019 in Italy, a country that banned asbestos in 1992. National and regional mortality rates for MM, and municipal standardized mortality ratios (all mesotheliomas, pleural (MPM) and peritoneal (MPeM)), by gender and age group were calculated. A municipal clustering analysis was also performed. There were 15,446 deaths from MM (11,161 males, 3.8 × 100,000; 4285 females, 1.1 × 100,000), of which 12,496 were MPM and 661 were MPeM. In the study period, 266 people ≤50 years died from MM. A slightly decreasing rate among males since 2014 was observed. The areas at major risk hosted asbestos-cement plants, asbestos mines (chrysotile in Balangero), shipyards, petrochemical and chemical plants, and refineries. Female mortality excesses particularly were found in municipalities with a fluoro-edenite-contaminated mine (Biancavilla) and textile facilities. Excesses were also found in a region with the presence of natural asbestos fibres and in males living in two small islands. The Italian National Prevention Plan stated recommendations to eliminate asbestos exposures and to implement health surveillance and healthcare for people exposed to asbestos.

Synthesis of Ni-Doped Tremolite Fibers to Help Clarify the Aetiology of the Cytotoxic Outcome of Asbestos

Asbestos fibers act as complex crystal-chemical reservoirs susceptible of releasing potentially toxic elements (such as ions impurities) into the lung cellular environment during permanency and dissolution. To comprehend the exact pathological mechanisms that are triggered upon inhalation of asbestos fibers, in vitro studies on possible interactions between the mineral and the biological system have been carried out mostly by using natural asbestos. However, this latter comprises intrinsic impurities such as Fe²⁺/Fe³⁺ and Ni²⁺ ions, and other eventual traces of metallic pathogens. Furthermore, often, natural asbestos is characterized by the co-presence of several mineral phases, fiber dimensions of which are randomly distributed in width and in length. For these reasons, it is albeit challenging to precisely identify toxicity factors and to define the accurate role of each factor in the overall pathogenesis of asbestos. In this regard, the availability of synthetic asbestos fibers with accurate chemical composition and specific dimensions for in vitro screening tests would represent the perfect tool to correlate asbestos toxicity to its chemico-physical features. Herein, to palliate such drawbacks of natural asbestos, well-defined Ni-doped tremolite fibers were chemically synthesized in order to offer biologists adequate samples for testing the specific role of Ni²⁺ in asbestos toxicity. The experimental conditions (temperature, pressure, reaction time and water amount) were optimized to produce batches of asbestos fibers of the tremolite phase, with uniformly distributed shape and dimensions and a controlled content of Ni²⁺ metal ions.

Association of mesothelioma deaths with the neighborhood asbestos exposure due to a large-scale asbestos-cement plant

A causal relationship between mesothelioma and the occupational asbestos exposure is well known, while few studies have shown a relationship to non-occupational exposures. The aim of this study was to quantify the risk of mesothelioma death associated with neighborhood asbestos exposures due to a large-scale asbestos-cement (AC) plant in Amagasaki, Japan, adjusting properly considerable risk factors including occupational exposures. We conducted a nested case-control study in which a fixed population of 143,929 residents who had been living in Amagasaki City between 1975 and 2002 were followed from 2002 to 2015. All 133 cases and 403 matched controls were interviewed about their occupational, domestic, household, and neighborhood asbestos exposures. Odds ratios (ORs) for mesothelioma death associated with the neighborhood exposure were estimated by a conditional logistic-regression model. For quantitative assessments for neighborhood exposure, we adopted cumulative indices for individuals' residential histories at each residence-specific asbestos concentration multiplied by the duration during the potential exposure period of 1957-1975 (crocidolite). We observed an increasing, dose-dependent risk of mesothelioma death associated with the neighborhood exposure, demonstrating that ORs in the highest quintile category were 21.4 (95% CI: 5.8 - 79.2) for all, 23.7 (95% CI: 3.8 -147.2) for males, and 26.0 (95% CI: 2.8 - 237.5) for females compared to the lowest quintile, respectively. A quantitative assessment for risk of mesothelioma deaths, adjusting for occupational and the other non-occupational exposures separately, showed a dose-dependent association with the neighborhood exposure and no substantial gender differences in magnitude.

Does the Presence of Asbestos-Containing Materials in Buildings Post-construction and Before Demolition Have an Impact on the Exposure to Occupants in Non-occupational Settings?

This narrative review aims to determine if asbestos-containing materials in buildings pose a hazard to building occupants in non-occupational settings. This paper is limited to the post-construction and pre-demolition stages of a building. The researchers selected 19 studies from the 126 studies screened, concerning exposure to asbestos fibers in non-occupational building settings, with a focus on post-construction and pre-demolition phases. The literature review found that certain conditions, such as the measurement techniques, standards, and previous data availability, prevent a conclusive answer to the research question. Some studies have pointed towards an effect of asbestos-containing materials on health of occupants in non-occupational settings. But, there are some that do not suggest a positive relationship between non-occupational exposure and the presence of asbestos-containing materials, and therefore these provide scope for further research, as these studies also do not rule out the relationship completely. The present study highlights the gaps in current knowledge and indicates areas for further research. Until conclusive evidence based on revised threshold standards and accurate measurement techniques is available, asbestos-containing materials may be considered unsafe for use in non-occupational settings, especially ones that young people and children occupy.

Incidence and mortality from malignant mesothelioma 1982-2020 and relationship with asbestos exposure: the Australian Mesothelioma Registry

OBJECTIVES

Malignant mesothelioma is an uncommon cancer associated with asbestos exposure, predominantly occupational. Asbestos has been banned in Australia since 2003 but mesothelioma has a long latency and incident cases continue to present. The Australian Mesothelioma Registry was incepted to collect systematic data about incidence and mortality alongside asbestos exposure.

METHODS

Benefiting from the Australian national system of cancer notification, all incident cases of mesothelioma in all states and territories are fast-tracked and notified regularly. Notified patients are contacted asking for consent to collect exposure information, initially by postal questionnaire and subsequently by telephone interview. Age-standardised annual incidence rates and mortality rates were calculated. Asbestos exposure was categorised as occupational, non-occupational, neither or, both; and as low, or high, probability of exposure.

RESULTS

Mesothelioma incidence appears to have peaked. The age-standardised incidence rates have declined steadily since the early 2000s (peaking in males at 5.9/100 000 and in all-persons at 3.2/100 000), driven by rates in males, who comprise the majority of diagnosed cases. Rates in women have remained fairly stable since that time. Age-standardised mortality rates have followed similar trends. Mesothelioma remains the most common in those aged over 80 years. Nearly all (94%) cases were linked with asbestos exposure (78% occupational in men; 6.8% in women).

CONCLUSIONS

With effective control of occupational asbestos use, the decline in age-standardised incidence and death rates has occurred. Incidence rates among women, in whom occupational asbestos exposure is rarely detectable, remain unchanged, pointing to the role of household and /or environmental asbestos exposure.

Manufactured doubt and the EPA 2020 chrysotile asbestos risk assessment

While all forms of asbestos have been determined to be carcinogenic to humans by the International Agency for Research on Cancer (IARC) as well as other authoritative bodies, the relative carcinogenic potency of chrysotile continues to be argued, largely in the context of toxic tort litigation. Relatively few epidemiologic studies have investigated only a single form of asbestos; however, one study that included an asbestos textile plant located in Marshville, North Carolina that processed chrysotile asbestos was used by the United States Environmental Protection Agency (EPA) in 2020 to help inform the agency's chrysotile asbestos risk assessment. During the EPA proceedings toxic tort defense consultants submitted comments to the EPA docket and made public presentations asserting that the Marshville plant had processed amphibole asbestos types and should not be used for the chrysotile risk assessment. A detailed evaluation of defense consultant assertions and supporting information and a full assessment of the available information concerning asbestos types used at the Marshville plant was undertaken. The preponderance of evidence continues to support the conclusion that neither amosite nor crocidolite were likely to have been processed in the Marshville textile plant. Defense consultants' assertions about chrysotile use are not supported by the preponderance of evidence and constitute an example of manipulation of information to cast uncertainty and doubt rather than to seek truth and contribute to the body of scientific evidence.

Asbestos dust concentrations and health conditions of workers at asbestos-cement corrugated sheet production manufacturers in Vietnam: a nationwide assessment

This study examined contemporary concentrations of asbestos dust during production and the health conditions of workers at asbestos-cement corrugated sheet production manufacturers in Vietnam. A nationwide survey was conducted on 28 factories (with 206 air samples) and 2459 workers. Asbestos fiber dust and the health status of workers were assessed. Results showed that 108/206 (52.4%) samples had asbestos fiber dust. The average concentration of asbestos fibers was 0.19 ± 0.14 fibers/ml. The percentage of workers with thickened pleural lesions/pleural calcification nodules was low. More studies are needed to evaluate the effectiveness of biomarkers in preventing the onset of lung cancer and mesothelioma in workers.

The Brazilian System for Monitoring Workers and General Population Exposed to Asbestos: Development, Challenges, and Opportunities for Workers' Health Surveillance

The lack of safe levels of asbestos exposure and the long latency of asbestos-related disease (ARD) makes workers' health surveillance challenging, especially in lower-income countries. This paper aims to present the recently developed Brazilian system for monitoring workers and general population exposed to asbestos (Datamianto), and to discuss the main challenges and opportunities for workers' health surveillance.

METHODS

a descriptive study of the Datamianto development process, examining all the stages of system planning, development, improvement, validation, availability, and training of health services for its use, in addition to presenting the main challenges and opportunities for its implementation.

RESULTS

The system was developed by a group of software developers, workers' health specialists, and practitioners, and it was recently incorporated by the Ministry of Health to be used for workers' health surveillance. It can facilitate the monitoring of exposed individuals, epidemiological data analysis, promote cooperation between health services, and ensure periodical medical screening guaranteed to workers by labor legislation. Moreover, the system has a Business Intelligence (BI) platform to analyze epidemiologic data and produce near real-time reports.

CONCLUSIONS

Datamianto can support and qualify the healthcare and surveillance of asbestos-exposed workers and ARD, promoting a better quality of life for workers and improving companies' compliance with legislation. Even so, the system's significance, applicability, and longevity will depend on the efforts aimed at its implementation and improvement.

Current causes of mesothelioma: how has the asbestos ban changed the perspective?

The association of mesothelioma, a lethal lung disease, with asbestos has led to an absolute ban on asbestos in at least 55 countries worldwide. The purpose of this paper is to review residual exposure to asbestos as well as other emerging causes of mesothelioma outside asbestos. The review provides detailed description of asbestos minerals, their geographical locations, mesothelioma in these areas, as well as contemporary possible sources of asbestos exposure. Second, we examine other emerging causes of mesothelioma including: ionizing radiation as the second most important risk factor after asbestos, particularly relevant to patients undergoing radiotherapy, third, carbon nanotubes which are under investigation and fourth, Simian virus 40. In the case of asbestos per se, the greatest risk is from occupational exposure during mining and subsequent processing. Of the non-occupational exposures, environmental exposure is most serious, followed by exposure from indoor asbestos minerals and secondary familial exposure. Overall, asbestos is still a major risk factor, but alternative causes should not be neglected, especially in young people, in women and those with a history of radiotherapy or living in high-risk locations.