Towards elimination of asbestos-related diseases: a theoretical basis for international cooperation

The Italian Experience in the Development of Mesothelioma Registries: A Pathway for Other Countries to Address the Negative Legacy of Asbestos

Asbestos (all forms, including chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophyllite) is carcinogenic to humans and causally associated with mesothelioma and cancer of the lung, larynx, and ovary. It is one of the carcinogens most diffuse in the world, in workplaces, but also in the environment and is responsible for a very high global cancer burden. A large number of countries, mostly with high-income economies, has banned the use of asbestos which, however, is still widespread in low- and middle-income countries. It remains, thus, one of the most common occupational and environmental carcinogens worldwide. Italy issued an asbestos ban in 1992, following the dramatic observation of a large increase in mortality from mesothelioma and other asbestos-related diseases in exposed workers and also in subjects with non-occupational exposure. A mesothelioma registry was also organized and still monitors the occurrence of mesothelioma cases, conducting a case-by-case evaluation of asbestos exposure. In this report, we describe two Italian communities, Casale Monferrato and Broni, that faced an epidemic of mesothelioma resulting from the production of asbestos cement and the diffuse environmental exposure; we present the activity and results of the Italian mesothelioma registry (ReNaM), describe the risk-communication activities at the local and national level with a focus on international cooperation and also describe the interaction between mesothelioma registration and medical services specialized in mesothelioma diagnosis and treatment in an area at high risk of mesothelioma. Finally, we assess the potential application of the solutions and methods already developed in Italy in a city in Colombia with high mesothelioma incidence associated with the production of asbestos-cement materials and the presence of diffuse environmental asbestos pollution.

Must countries shoulder the burden of mesothelioma to ban asbestos? A global assessment

INTRODUCTION

Mesothelioma is a key asbestos-related disease (ARD) but can be difficult to diagnose. Countries presumably ban asbestos to reduce future ARD burdens, but it is unknown if countries ban asbestos as a consequence of ARD burdens. We assessed if and to what extent mesothelioma burden has an impact on a country banning asbestos and obtaining targets for preventative strategies.

METHODS

We analysed the status of asbestos ban and mesothelioma burden during 1990-2019 in 198 countries. We assessed mesothelioma burden by age-adjusted mortality rates (MRs) estimated by the Global Burden of Disease Study (GBD) and mesothelioma identification by the WHO mortality database. For GBD-estimated mesothelioma MR, the pre-ban period in the asbestos-banned countries was compared with the 1990-2019 period in the not-banned countries. For mesothelioma identification, the 1990-2019 period was applied to both banned and not-banned countries.

RESULTS

The association of mesothelioma MR with ban status increased as the ban year approached. Logistic regression analyses showed that the odds of a country banning asbestos increased 14.1-fold (95% CI 5.3 to 37.9) for mesothelioma identification combined with a 26% (12% to 42%) increase per unit increase of mesothelioma MR (one death per million per year) during the period 1-5 year before ban (model p<0.0001).

CONCLUSION

Mesothelioma burden had an impact on, and together with its identification, explained the banning of asbestos in many countries. Asbestos-banned countries likely learnt lessons from their historical policies of using asbestos because mesothelioma burden and identification follow historical asbestos use. Prevention targets for ARD elimination should combine asbestos ban with mesothelioma identification.

Radiographic Changes in Colombian Asbestos Factory Workers

Background:

Until recently, Colombia has been a country actively using asbestos. A major factory in Bogota manufactures friction products.

Objective:

To determine if the use of chrysotile asbestos in a friction products facility leads to workers developing disease.

Methods:

One hundred forty-eight factory workers, former workers, or retirees volunteered for X-ray and pulmonary function testing after informed consent. X-rays were read by two readers who needed to agree on positive findings.

Results:

Nineteen of the 148 X-rays had changes consistent with the known prior exposure to asbestos, mostly parenchymal in nature. Pulmonary function was not altered in most of the studied population.

Conclusion:

Asbestos disease is clearly present among Colombian asbestos factory workers, as is seen in other exposed populations around the world.

Drug repurposing in malignant pleural mesothelioma: a breath of fresh air?

Drug repurposing is the use of known drugs for new indications. Malignant pleural mesothelioma (MPM) is a rare cancer with a poor prognosis. So far, few treatments have been approved in this disease. However, its incidence is expected to increase significantly, particularly in developing countries. Consequently, drug repurposing appears as an attractive strategy for drug development in MPM, since the known pharmacology and safety profile based on previous approvals of repurposed drugs allows for faster time-to-market for patients and lower treatment cost. This is critical in low- and middle-income countries where access to expensive drugs is limited. This review assesses the published preclinical and clinical data about drug repurposing in MPM.In this review, we identified 11 therapeutic classes that could be repositioned in mesothelioma. Most of these treatments have been evaluated in vitro, half have been evaluated in vivo in animal models of MPM and only three (i.e. valproate, thalidomide and zoledronic acid) have been investigated in clinical trials, with limited benefits so far. Efforts could be coordinated to pursue further investigations and test promising drugs identified in preclinical experiments in appropriately designed clinical trials.

Elimination of asbestos use and asbestos-related diseases: an unfinished story

Asbestos is a proven human carcinogen. Asbestos-related diseases (ARDs) typically comprise lung cancer, malignant mesothelioma, asbestosis, pleural plaques, thickening and effusion. International organizations, notably the World Health Organization and the International Labour Organization, have repeatedly declared the need to eliminate ARDs, and have called on countries to stop using asbestos. However, the relevant national-level indicators (e.g., incidence/mortality rates and per capita asbestos use, as well as their interrelationships) indicate that ARDs are increasing and asbestos use is continuing in the world. Lessons learned by industrialized countries in terms of policy and science have led to a growing number of countries adopting bans. In contrast, industrializing countries are faced with a myriad of forces prompting them to continue using asbestos. Full-scale international cooperation will thus be needed, with industrialized countries sharing their experiences and technologies to enable industrializing countries to make smooth transitions to banned states and achieve the goal of eliminating ARDs.

Global mesothelioma deaths reported to the World Health Organization between 1994 and 2008

OBJECTIVE

To carry out a descriptive analysis of mesothelioma deaths reported worldwide between 1994 and 2008.

METHODS

We extracted data on mesothelioma deaths reported to the World Health Organization mortality database since 1994, when the disease was first recorded. We also sought information from other English-language sources. Crude and age-adjusted mortality rates were calculated and mortality trends were assessed from the annual percentage change in the age-adjusted mortality rate.

FINDINGS

In total, 92,253 mesothelioma deaths were reported by 83 countries. Crude and age-adjusted mortality rates were 6.2 and 4.9 per million population, respectively. The age-adjusted mortality rate increased by 5.37% per year and consequently more than doubled during the study period. The mean age at death was 70 years and the male-to-female ratio was 3.6:1. The disease distribution by anatomical site was: pleura, 41.3%; peritoneum, 4.5%; pericardium, 0.3%; and unspecified sites, 43.1%. The geographical distribution of deaths was skewed towards high-income countries: the United States of America reported the highest number, while over 50% of all deaths occurred in Europe. In contrast, less than 12% occurred in middle- and low-income countries. The overall trend in the age-adjusted mortality rate was increasing in Europe and Japan but decreasing in the United States.

CONCLUSION

The number of mesothelioma deaths reported and the number of countries reporting deaths increased during the study period, probably due to better disease recognition and an increase in incidence. The different time trends observed between countries may be an early indication that the disease burden is slowly shifting towards those that have used asbestos more recently.