Updated Italian cohort data continues to confirm lack of mesothelioma risk in pooled cohort of international cosmetic talc miners and millers

OBJECTIVES

To assess potential mesothelioma risk following inhalation of cosmetic talc, we updated previous iterations of a pooled cohort analysis, post-study statistical power analysis, and confidence interval function analysis for a pooled cohort of international cosmetic talc miners/millers given new Italian cohort data.

METHODS

Five cohorts of cosmetic talc miners/millers were pooled. Expected numbers of mesotheliomas for each cohort were reported by the original authors. We based our post-study statistical power analysis on an a priori one-sided significance level of 0.05, and exact Poisson and approximate distribution probabilities. To evaluate the confidence interval function for the observed pooled mesothelioma standardized mortality ratios (SMRs), we calculated the probability for the upper 100(1-2α)% confidence limit that equals various SMRs of interest.

RESULTS

The pooled cohorts generated a total observation time of 135,524.38 person-years. Overall, 4.14 mesotheliomas were expected (mid-value estimate), though only one case of mesothelioma has been confirmed in the pooled cohort to date. We calculated 71% and 87% post-study power to detect a 2.5-fold or greater and a 3.0-fold or greater increase in mesothelioma, respectively. Our complimentary confidence interval function analysis demonstrated that the probability that the true mesothelioma SMR for the pooled cohort was at or above 2.0 or at or above 3.0 was 0.00235 and 0.00005, respectively.

CONCLUSIONS

Based on the updated results of our various analyses, the current epidemiological evidence from cosmetic talc miner/miller cohort studies continues to not support the hypothesis that the inhalation of cosmetic talc is associated with an increased risk of mesothelioma.

Spatial Analysis of Shared Risk Factors between Pleural and Ovarian Cancer Mortality in Lombardy (Italy)

Background: Asbestos exposure is a recognized risk factor for ovarian cancer and malignant mesothelioma. There are reports in the literature of geographical ecological associations between the occurrence of these two diseases. Our aim was to further explore this association by applying advanced Bayesian techniques to a large population (10 million people). Methods: We specified a series of Bayesian hierarchical shared models to the bivariate spatial distribution of ovarian and pleural cancer mortality by municipality in the Lombardy Region (Italy) in 2000–2018. Results: Pleural cancer showed a strongly clustered spatial distribution, while ovarian cancer showed a less structured spatial pattern. The most supported Bayesian models by predictive accuracy (widely applicable or Watanabe–Akaike information criterion, WAIC) provided evidence of a shared component between the two diseases. Among five municipalities with significant high standardized mortality ratios of ovarian cancer, three also had high pleural cancer rates. Wide uncertainty was present when addressing the risk of ovarian cancer associated with pleural cancer in areas at low background risk of ovarian cancer. Conclusions: We found evidence of a shared risk factor between ovarian and pleural cancer at the small geographical level. The impact of the shared risk factor can be relevant and can go unnoticed when the prevalence of other risk factors for ovarian cancer is low. Bayesian modelling provides useful information to tailor epidemiological surveillance.

Pleural Fluid Has Pro-Growth Biological Properties Which Enable Cancer Cell Proliferation

Objectives

Patients with malignant pleural mesothelioma (MPM) or pleural metastases often present with malignant pleural effusion (MPE). This study aimed to analyze the effect of pleural fluid on cancer cells.

Materials and Methods

Established patient-derived cancer cell cultures derived from MPE (MPM, breast carcinoma, lung adenocarcinoma) were seeded in 100% pleural fluid (exudate MPM MPE, transudate MPE, non-MPE transudate fluid) and proliferation was monitored. In addition, the establishment of new MPM cell cultures, derived from MPE specimens, was attempted by seeding the cells in 100% MPE fluid.

Results

All established cancer cell cultures proliferated with similar growth rates in the different types of pleural fluid. Primary MPM cell culture success was similar with MPE fluid as with full culture medium.

Conclusions

Pleural fluid alone is adequate for cancer cell proliferation in vitro, regardless of the source of pleural fluid. These results support the hypothesis that pleural fluid has important pro-growth biological properties, but the mechanisms for this effect are unclear and likely not malignant effusion specific.

Recovering missing mesothelioma deaths in death certificates using hospital records

BACKGROUND

In Brazil, underreporting of mesothelioma and cancer of the pleura (MCP) is suspected to be high. Records from death certificates (SIM) and hospital registers (SIH-SUS) can be combined to recover missing data but only anonymous databases are available. This study shows how common data can be used for linkage and as an assessment of accuracy.

METHODS

Mesothelioma (all sites, ICD-10 codes C45.0-C45.9) and cancer of the pleura (C38.4) were retrieved from both information systems and combined using a linkage algorithm. Accuracy was examined with non-anonymous databases, limited to the state of São Paulo.

RESULTS

We found 775 cases in death certificates and 283 in hospital registers. The linkage matched 57 cases, all accurately paired. Three cases, 0.4% in SIM and 1.3% in SIH-SUS, could not be matched because of data inconsistencies.

CONCLUSIONS

A computer linkage can recover MCP cases from hospital records not found in death certificates in Brazil.

Mortality from cancer and other causes among Italian chrysotile asbestos miners

OBJECTIVE

To investigate the long-term mortality of a cohort of Italian asbestos miners.

METHODS

The cohort included 1056 men employed in a chrysotile mine between 1930 and 1990, who were followed up during 1946-2014, for a total of 37 471 person-years of observation. Expected deaths and SMRs were computed using national and local (after 1980, when available) reference.

RESULTS

A total of 294 (27.8%) subjects were alive and at the end of follow-up, 722 (68.4%) were dead and 40 (3.8%) were lost to follow-up. The SMR for overall mortality was 1.35 (95%CI 1.25 to 1.45). The SMR for pleural cancer, based on seven observed deaths, was 5.54 (95% CI 2.22 to 11.4) and related to time since first exposure, but not to duration of employment, cumulative exposure or time since last exposure. The SMR for lung cancer was 1.16 (95% CI 0.87 to 1.52; 53 observed deaths), with no excess among workers with cumulative exposure below 100 fibre/mL-years (SMR 0.82; 95% CI 0.44 to 1.40).

CONCLUSIONS

The update of the follow-up of this cohort confirmed an increased mortality from pleural cancer mortality in miners exposed to chrysotile and a lack of significant increase in lung cancer mortality.

Updated mortality study of a cohort of asbestos textile workers

Limited information is available on risk of peritoneal mesothelioma after asbestos exposure, and in general on the risk of cancer after cessation of asbestos exposure. We updated to 2013 the follow-up of a cohort of 1083 female and 894 male textile workers with heavy asbestos exposure (up to 100 fb/mL), often for short periods. A total of 1019 deaths were observed, corresponding to a standardized mortality ratio (SMR) of 1.68 (95% confidence interval [CI]: 1.57-1.78). SMRs were 29.1 (95% CI: 21.5-38.6) for peritoneal cancer, 2.96 (95% CI: 2.50-3.49) for lung cancer, 33.7 (95% CI: 25.7-43.4) for pleural cancer, and 3.03 (95% CI: 1.69-4.99) for ovarian cancer. For pleural and peritoneal cancer, there was no consistent pattern of risk in relation to time since last exposure, whereas for lung cancer there was an indication of a decline in risk after 25 years since last exposure. The findings of this unique cohort provide novel data for peritoneal cancer, indicating that - as for pleural cancer - the excess risk does not decline up to several decades after cessation of exposure.

Pleural cancer mortality in Spain: time-trends and updating of predictions up to 2020

BACKGROUND

A total of 2,514,346 metric tons (Mt) of asbestos were imported into Spain from 1906 until the ban on asbestos in 2002. Our objective was to study pleural cancer mortality trends as an indicator of mesothelioma mortality and update mortality predictions for the periods 2011-2015 and 2016-2020 in Spain.

METHODS

Log-linear Poisson models were fitted to study the effect of age, period of death and birth cohort (APC) on mortality trends. Change points in cohort- and period-effect curvatures were assessed using segmented regression. Fractional power-link APC models were used to predict mortality until 2020. In addition, an alternative model based on national asbestos consumption figures was also used to perform long-term predictions.

RESULTS

Pleural cancer deaths increased across the study period, rising from 491 in 1976-1980 to 1,249 in 2006-2010. Predictions for the five-year period 2016-2020 indicated a total of 1,319 pleural cancer deaths (264 deaths/year). Forecasts up to 2020 indicated that this increase would continue, though the age-adjusted rates showed a levelling-off in male mortality from 2001 to 2005, corresponding to the lower risk in post-1960 generations. Among women, rates were lower and the mortality trend was also different, indicating that occupational exposure was possibly the single factor having most influence on pleural cancer mortality.

CONCLUSION

The cancer mortality-related consequences of human exposure to asbestos are set to persist and remain in evidence until the last surviving members of the exposed cohorts have disappeared. It can thus be assumed that occupationally-related deaths due to pleural mesothelioma will continue to occur in Spain until at least 2040.

The European mesothelioma epidemic

Projections for the period 1995-2029 suggest that the number of men dying from mesothelioma in Western Europe each year will almost double over the next 20 years, from 5000 in 1998 to about 9000 around 2018, and then decline, with a total of about a quarter of a million deaths over the next 35 years. The highest risk will be suffered by men born around 1945-50, of whom about 1 in 150 will die of mesothelioma. Asbestos use in Western Europe remained high until 1980, and substantial quantities are still used in several European countries. These projections are based on the fit of a simple age and birth cohort model to male pleural cancer mortality from 1970 to 1989 for six countries (Britain, France, Germany, Italy, The Netherlands and Switzerland) which together account for three-quarters of the population of Western Europe. The model was tested by comparing observed and predicted numbers of deaths for the period 1990-94. The ratio of mesothelioma to recorded pleural cancer mortality has been 1.6:1 in Britain but was assumed to be 1:1 in other countries.