Personal protective equipment for preventing asbestos exposure in workers.

BACKGROUND: Asbestos exposure can lead to asbestos-related diseases. The European Union (EU) has adopted regulations for workplaces where asbestos is present. The EU occupational exposure limit (OEL) for asbestos is 0.1 fibres per cubic centimetre of air (f/cm3) as an eight-hour average. Different types of personal protective equipment (PPE) are available to provide protection and minimise exposure; however, their effectiveness is unclear. OBJECTIVES: To assess the effects of personal protective equipment (PPE), including donning and doffing procedures and individual hygienic behaviour, compared to no availability and use of such equipment or alternative equipment, on asbestos exposure in workers in asbestos demolition and repair work. SEARCH METHODS: We searched MEDLINE, Embase, CENTRAL, and Scopus (September 2022), and we checked the reference lists of included studies. SELECTION CRITERIA: We included studies that measured asbestos concentration outside and inside PPE (considering outside concentration a surrogate for no PPE), exposure to asbestos after doffing PPE, donning and doffing errors, nonadherence to regulations, and adverse effects of PPE. DATA COLLECTION AND ANALYSIS: Two review authors selected studies, extracted data, and assessed risk of bias using ROBINS-I. We categorised PPE as full-face filtering masks, supplied air respirators (SARs), and powered air-purifying respirators (PAPRs). Values for asbestos outside and inside PPE were transformed to logarithmic values for random-effects meta-analysis. Pooled logarithmic mean differences (MDs) were exponentiated to obtain the ratio of means (RoM) and 95% confidence interval (95% CI). The RoM shows the degree of protection provided by the respirators (workplace protection factor). Since the RoM is likely to be much higher at higher outside concentrations, we presented separate results according to the outside asbestos concentration, as follows. • Below 0.01 f/cm3 (band 1) • 0.01 f/cm3 to below 0.1 f/cm3 (band 2) • 0.1 f/cm3 to below 1 f/cm3 (band 3) • 1 f/cm3 to below 10 f/cm3 (band 4) • 10 f/cm3 to below 100 f/cm3 (band 5) • 100 f/cm3 to below 1000 f/cm3 (band 6) Additionally, we determined whether the inside concentrations per respirator and concentration band complied with the current EU OEL (0.1 f/cm3) and proposed EU OEL (0.01 f/cm3). MAIN RESULTS: We identified six studies that measured asbestos concentrations outside and inside respiratory protective equipment (RPE) and one cross-over study that compared the effect of two different coveralls on body temperature. No studies evaluated the remaining predefined outcomes. Most studies were at overall moderate risk of bias due to insufficient reporting. The cross-over study was at high risk of bias. Full-face filtering masks Two studies evaluated full-face filtering masks. They provided insufficient data for band 1 and band 6. The results for the remaining bands were as follows. • Band 2: RoM 19 (95% CI 17.6 to 20.1; 1 study, 3 measurements; moderate certainty) • Band 3: RoM 69 (95% CI 26.6 to 175.9; 2 studies, 17 measurements; very low certainty) • Band 4: RoM 455 (95% CI 270.4 to 765.1; 1 study, 16 measurements; low certainty) • Band 5: RoM 2752 (95% CI 1236.5 to 6063.2;1 study, 3 measurements; low certainty) The inside measurements in band 5 did not comply with the EU OEL of 0.1 f/cm3, and no inside measurements complied with the proposed EU OEL of 0.01 f/cm3. Supplied air respirators Two studies evaluated supplied air respirators. They provided no data for band 6. The results for the remaining bands were as follows. • Band 1: RoM 11 (95% CI 7.6 to 14.9; 1 study, 134 measurements; moderate certainty) • Band 2: RoM 63 (95% CI 43.8 to 90.9; 1 study, 17 measurements; moderate certainty) • Band 3: RoM 528 (95% CI 368.7 to 757.5; 1 study, 38 measurements; moderate certainty) • Band 4: RoM 4638 (95% CI 3071.7 to 7044.5; 1 study, 49 measurements; moderate certainty) • Band 5: RoM 26,134 (16,647.2 to 41,357.1; 1 study, 22 measurements; moderate certainty) All inside measurements complied with the current OEL of 0.1 f/cm3 and the proposed OEL of 0.01 f/cm3. Powered air-purifying respirators Three studies evaluated PAPRs. The results per band were as follows. • Band 1: RoM 8 (95% CI 3.7 to 19.1; 1 study, 23 measurements; moderate certainty) • Band 2: RoM 90 (95% CI 64.7 to 126.5; 1 study, 17 measurements; moderate certainty) • Band 3: RoM 104 (95% CI 23.1 to 464.1; 3 studies, 14 measurements; very low certainty) • Band 4: RoM 706 (95% CI 219.2 to 2253.0; 2 studies, 43 measurements; very low certainty) • Band 5: RoM 1366 (544.6 to 3428.9; 2 studies, 8 measurements; low certainty) • Band 6: RoM 18,958 (95% CI 4023.9 to 90,219.4; 2 studies, 13 measurements; very low certainty) All inside measurements complied with the 0.1 f/cm3 OEL when the outside concentration was below 10 f/cm3 (band 1 to band 4). From band 3, no measurements complied with the proposed OEL of 0.01 f/cm3. Different types of coveralls One study reported the adverse effects of coveralls. A polyethylene suit may increase the body temperature more than a ventilated impermeable polyvinyl (PVC) coverall, but the evidence is very uncertain (MD 0.17 °C, 95% CI -0.08 to 0.42; 1 study, 11 participants; very low certainty). AUTHORS' CONCLUSIONS: Where the outside asbestos concentration is below 0.1 f/cm3, SARS and PAPRs likely reduce exposure to below the proposed OEL of 0.01 f/cm3. For outside concentrations up to 10 f/cm3, all respirators may reduce exposure below the current OEL, but only SAR also below the proposed OEL. In band 5 (10 to < 100 f/cm3), full-face filtering masks may not reduce asbestos exposure below either OEL, SARs likely reduce exposure below both OELs, and there were no data for PAPRs. In band 6 (100 f/cm3 to < 1000 f/cm3), PAPRs may not reduce exposure below either OEL, and there were no data for full-face filtering masks or SARs. Some coveralls may increase body temperature more than others. Randomised studies are needed to directly compare PAPRs and SARs at higher asbestos concentrations and to assess adverse effects. Future studies should assess the effects of doffing procedures.

Analysis of invasive diagnostic techniques for pathological confirmation of pleural mesothelioma.

BACKGROUND AND OBJECTIVES: Mesothelioma is an infrequent neoplasm with a poor prognosis that is related to exposure to asbestos and whose peak incidence in Europe is estimated from 2020. Its diagnosis is complex; imaging techniques and the performance of invasive pleural techniques being essential for pathological confirmation. The different diagnostic yields of these invasive techniques are collected in the medical literature. The present work consisted of reviewing how the definitive diagnosis of mesothelioma cases in our centre was reached to check if there was concordance with the data in the bibliography. MATERIALS AND METHODS: Retrospective review of patients with a diagnosis of pleural mesothelioma in the period 2019-2021, analysing demographic data and exposure to asbestos, the semiology of the radiological findings and the invasive techniques performed to reach the diagnosis. RESULTS: Twenty-six mesothelioma cases were reviewed. 22 men and 4 women. Median age 74 years. 9 patients had a history of asbestos exposure. Moderate-severe pleural effusion was the most frequent radiological finding (23/26). The sensitivity of the invasive techniques was as follows: Cytology 13%, biopsy without image guidance 11%, image-guided biopsy 93%, surgical biopsy 67%. CONCLUSIONS: In our review, pleural biopsy performed with image guidance was the test that had the highest diagnostic yield, so it should be considered as the initial invasive test for the study of mesothelioma.

Cholangiocarcinoma and Occupational Exposure to Asbestos: Insights From the Italian Pooled Cohort Study.

BACKGROUND: Recent studies supported the association between occupational exposure to asbestos and risk of cholangiocarcinoma (CC). Aim of the present study is to investigate this association using an update of mortality data from the Italian pooled asbestos cohort study and to test record linkage to Cancer Registries to distinguish between hepatocellular carcinoma (HCC) and intrahepatic/extrahepatic forms of CC. METHODS: The update of a large cohort study pooling 52 Italian industrial cohorts of workers formerly exposed to asbestos was carried out. Causes of death were coded according to ICD. Linkage was carried out for those subjects who died for liver or bile duct cancer with data on histological subtype provided by Cancer Registries. RESULTS: 47 cohorts took part in the study (57,227 subjects). We identified 639 causes of death for liver and bile duct cancer in the 44 cohorts covered by Cancer Registry. Of these 639, 240 cases were linked to Cancer Registry, namely 14 CC, 83 HCC, 117 cases with unspecified histology, 25 other carcinomas, and one case of cirrhosis (likely precancerous condition). Of the 14 CC, 12 occurred in 2010-2019, two in 2000-2009, and none before 2000. CONCLUSION: Further studies are needed to explore the association between occupational exposure to asbestos and CC. Record linkage was hampered due to incomplete coverage of the study areas and periods by Cancer Registries. The identification of CC among unspecific histology cases is fundamental to establish more effective and targeted liver cancer screening strategies.

Asbestos and disease - a public health success story?

OBJECTIVE: This paper discusses the failure and success of society to decrease the adverse health effects of asbestos exposure on workers' health in relation to scientific knowledge. METHODS: The findings are based on a narrative literature review. RESULTS: Early warnings of the adverse health effects of workplace exposure to asbestos were published already in the 1930s. Serious health effects, such as malignancies and fibrosis due to occupational asbestos exposure, were highlighted in major medical journals and textbooks in late 1960s. New technologies could detect also asbestos fibers in the lung of non-occupational exposed persons in the 1970s. The first bans for using asbestos came in the early 1970s, and more general bans by authorities came in the 1980s and continue until today. CONCLUSIONS: The rather late recognition of adverse effects of asbestos exposure in the general population and measures to decrease the exposure through more general bans came rather late. However, the very strong measures such as general bans in many countries have been a success. A Swedish study showed that the general ban and other measures have decreased the risk of malignancies due to occupational exposure. The effect of the bans on adverse effects in the general population has yet to be studied. Analysis of fibers in the lungs of persons born after the bans could be an efficient method.

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.

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.

Quantitative Assessment of Asbestos Fibers in Abdominal Organs: A Scoping Review.

BACKGROUND: Quantification of asbestos fibers has been mainly performed in the lung but rarely in other organs. However, this may be relevant to understanding better translocation pathways and the oncogenic effects of asbestos on the human body. Electron microscopy is the best technology available to assess the type of fiber, dimensions, and distribution of asbestos fibers in different tissues and as a biomarker of cumulative dose. OBJECTIVES: This scoping review aims to summarize the findings of the studies in which asbestos fibers have been quantified by electron microscopy, occasionally associated with X-ray microanalysis, in normal and pathological tissue of ten abdominal organs. METHODS: A scoping review has been performed by searching articles that quantified asbestos fibers in abdominal organs by electron microscopy (Scanning- SEM or Transmission- TEM). RESULTS: The 12 selected studies included 204 cases, and 325 samples were analyzed. The colon and rectum, kidney, bladder, and abdominal lymph nodes were the organs with at least ten samples available with quantification of asbestos fibers. Asbestos fibers were detected in all the abdominal organs considered: the highest value (152,32 million fibers per gram of dry tissue) was found in the colon and was identified using STEM with EDS. CONCLUSION: The studies included were heterogeneous in terms of exposure and cases, type of samples, as well as analytical techniques, therefore we cannot confirm a specific pattern of distribution in any organ, based on the low homogeneity of the exposure status. The colon is the organ in which the number of fibers is the highest, probably because of exposure arising from both internal distribution of inhaled fibers and ingestion. Additional studies of the number of asbestos fibers in abdominal organs should be made to achieve better representativity.

Occupational Risk Factors for Laryngeal Cancer in Tunisia: A Case Control Study.

BACKGROUND: Tobacco use and alcohol consumption are the primary risk factors for laryngeal cancer (LC). In most populations, occupational exposures are likely to play a minor role in laryngeal carcinogenesis. We aimed to investigate the association between occupational exposure and laryngeal cancer. METHODS: It is a case-control study that included 140 cases diagnosed between January 2013 and December 2016 and 140 controls matched by sex, age, alcohol consumption, and tobacco consumption. RESULTS: Significantly increased risks were found amongst workers of the building sector (OR=4.621; 95% CI [1.826-11.693]) and the mechanical industry sector (OR=5.074; 95% CI [1.425-18.072]). Significant association of laryngeal cancer with various carcinogens was observed such as asbestos (p=0.009; OR=3.68; 95% CI [1.29-10.46]), paint vapors (p=0.005; OR=3.35; 95% CI [1.37-8.16]), solvents (p=0.001; OR=3.29: 95% CI [1.61-6.68]) and cement dust (p=0.003; OR=3.19: 95% CI [1.43-7.12]). After binary logistic regression, cement dust was independently correlated with LC (p=0.042; OR=3.93; 95% CI [1.04-14.78]. The administration sector was associated with decreased risk (p=0.001; OR=0.07; 95% CI [0.03-0.15]) as well as the health sector (p=0.001; OR=0.098; 95% CI [0.02-0.43]). CONCLUSIONS: Our results supported the role of occupational factors in developing LC. Further studies enabling an in-depth analysis of occupational exposures are necessary to provide a clearer definition of the etiological associations between single agents and circumstances of exposure and the genesis of LC.

Occupational asbestos exposure and ovarian cancer: updated systematic review.

BACKGROUND: The association between asbestos exposure and ovarian cancer has been questioned given the possible misdiagnosis of peritoneal mesothelioma as ovarian cancer. AIMS: To update a systematic review on ovarian cancer risk in women occupationally exposed to asbestos, exploring the association with the time since first exposure and the duration of exposure. METHODS: We searched PubMed from 2008 onwards, screened previous systematic reviews, combined standardized mortality ratios (SMR) using random effect models and quantified heterogeneity using the I2 statistic. To assess tumour misclassification, we compared the distribution of observed excess ovarian cancers (OEOC) to that expected (EEOC) from the distribution of peritoneal cancers in strata of latency and exposure duration. RESULTS: Eighteen publications (20 populations), including a pooled analysis of 21 cohorts, were included. The pooled SMR was 1.79 (95% confidence interval 1.38-2.31), with moderate heterogeneity between studies (I2 = 42%), based on 144 ovarian cancer deaths/cases. The risk was increased for women with indirect indicators of higher exposure, longer duration and latency, and lower for chrysotile than for crocidolite exposure. The effect of duration and latency could not be completely disentangled, since no multivariate analysis was available for time-related variables. The dissimilarity index between OEOC and EEOC for the time since first exposure was small suggesting a similar pattern of risk. CONCLUSIONS: While some misclassification between ovarian and peritoneal cancers cannot be excluded, the observed excess risk of ovarian cancer should be added to the overall disease burden of asbestos.

The association of genetic factors with serum calretinin levels in asbestos-related diseases.

BACKGROUND: Asbestos exposure is associated with different asbestos-related diseases, including malignant mesothelioma (MM). MM diagnosis is confirmed with immunohistochemical analysis of several markers, including calretinin. Increased circulating calretinin was also observed in MM. The aim of the study was to determine if CALB2 polymorphisms or polymorphisms in genes that can regulate calretinin expression are associated with serum calretinin levels or MM susceptibility. SUBJECTS AND METHODS: The study included 288 MM patients and 616 occupationally asbestos-exposed subjects without MM (153 with asbestosis, 380 with pleural plaques and 83 without asbestos-related disease). Subjects were genotyped for seven polymorphisms in CALB2, E2F2, MIR335, NRF1 and SEPTIN7 genes using competitive allele-specific polymerase chain reaction (PCR). Serum calretinin was determined with ELISA in 545 subjects. Nonparametric tests, logistic regression and receiver operating characteristic (ROC) curve analysis were used for statistical analysis. RESULTS: Carriers of at least one polymorphic CALB2 rs889704 allele had lower calretinin levels (P = 0.036). Carriers of two polymorphic MIR335 rs3807348 alleles had higher calretinin (P = 0.027), while carriers of at least one polymorphic NRF1 rs13241028 allele had lower calretinin levels (P = 0.034) in subjects without MM. Carriers of two polymorphic E2F2 rs2075995 alleles were less likely to develop MM (odds ratio [OR] = 0.64, 95% confidence interval [CI] = 0.43-0.96, P = 0.032), but the association was no longer significant after adjustment for age (P = 0.093). Optimal serum calretinin cut-off values differentiating MM patients from other subjects differed according to CALB2, NRF1, E2F2, and MIR335 genotypes. CONCLUSIONS: The results of presented study suggest that genetic variability could influence serum calretinin levels. These findings could contribute to a better understanding of calretinin regulation and potentially to earlier MM diagnosis.

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.

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.

Incidence of mesothelioma in young people and causal exposure to asbestos in the Italian national mesothelioma registry (ReNaM).

INTRODUCTION: The epidemiological surveillance of mesothelioma incidence is a crucial key for investigating the occupational and environmental sources of asbestos exposure. The median age at diagnosis is generally high, according to the long latency of the disease. The purposes of this study are to analyse the incidence of mesothelioma in young people and to evaluate the modalities of asbestos exposure. METHODS: Incident malignant mesothelioma (MM) cases in the period 1993-2018 were retrieved from Italian national mesothelioma registry and analysed for gender, incidence period, morphology and exposure. Age-standardised rates have been calculated and the multiple correspondence analysis has been performed. The association between age and asbestos exposure has been tested by χ2 test. RESULTS: From 1993 to 2018, 30 828 incident MM cases have been collected and 1278 (4.1%) presented diagnosis at early age (≤50 years). There is a substantial association between age at diagnosis and the type of asbestos exposure and a significantly lower frequency of cases with occupational exposure to asbestos (497 cases vs 701 expected) in young people has been documented. Paraoccupational and environmental exposure to asbestos have been found more frequent in young MM cases (85 and 93 observed cases vs 52 and 44 expected cases, respectively). CONCLUSIONS: Mesothelioma incidence surveillance at population level and the anamnestic individual research of asbestos exposure is a fundamental tool for monitoring asbestos exposure health effects, supporting the exposure risks prevention policies. Clusters of mesothelioma incident cases in young people are a significant signal of a potential non-occupational exposure to asbestos.

Deep Learning Neural Network-Guided Detection of Asbestos Bodies in Bronchoalveolar Lavage Samples.

INTRODUCTION: Asbestos is a global occupational health hazard, and exposure to it by inhalation predisposes to interstitial as well as malignant pulmonary morbidity. Over time, asbestos fibers embedded in lung tissue can become coated with iron-rich proteins and mucopolysaccharides, after which they are called asbestos bodies (ABs) and can be detected in light microscopy (LM). Bronchoalveolar lavage, a cytological sample from the lower airways, is one of the methods for diagnosing lung asbestosis and related morbidity. Search for ABs in these samples is generally laborious and time-consuming. We describe a novel diagnostic method, which implements deep learning neural network technology for the detection of ABs in bronchoalveolar lavage samples (BALs). METHODS: BALs with suspicion of asbestos exposure were scanned as whole slide images (WSIs) and uploaded to a cloud-based virtual microscopy platform with a neural network training interface. The images were used for training and testing a neural network model capable of recognizing ABs. To prioritize the model's sensitivity, we allowed it to also make false-positive suggestions. To test the model, we compared its performance to standard LM diagnostic data as well as the ground truth (GT) number of ABs, which we established by a thorough manual search of the WSIs. RESULTS: We were able to reach overall sensitivity of 93.4% (95% CI: 90.3-95.7%) in the detection of ABs in comparison to their GT number. Compared to standard LM diagnostic data, our model showed equal to or higher sensitivity in most cases. CONCLUSION: Our results indicate that deep learning neural network technology offers promising diagnostic tools for routine assessment of BALs. However, at this stage, a human expert is required to confirm the findings.

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).