There are different forms of asbestos, broadly divided into the amphibole (actinolite, amosite, anthophyllite, crocidolite, and tremolite) and serpentine (chrysotile) groups. Chrysotile is the most used form of asbestos worldwide and the only one that is commercially mined today.
All forms of asbestos are known to cause cancer in humans (as concluded in the IARC Monographs (1)). The most recent IARC Monograph on this topic concluded that there is sufficient evidence that asbestos causes cancers of the lung, larynx, and ovary as well as mesothelioma (1). The Monograph also reported that positive associations have been observed between asbestos and cancers of the stomach, pharynx, and colorectum. The World Health Assembly, in Resolution WHA 60.26, requested the World Health Organization (WHO) to conduct global campaigns for the elimination of asbestos-related diseases. WHO, in collaboration with the International Labour Organization and other intergovernmental organizations and civil society, has recognized that stopping the use of all forms of asbestos is the most efficient way to eliminate asbestos-related diseases (WHO Fact Sheet No. 343).
As with most identified carcinogens, there are still unanswered questions to be addressed about chrysotile. Because chrysotile has different chemical and physical properties to other asbestos fibres, it is important to conduct studies specifically of chrysotile to improve knowledge about its carcinogenicity, as distinct from that of amphibole asbestos or mixtures of chrysotile and amphiboles.
The current study seeks to contribute to filling the gaps in understanding about chrysotile with continued research, needed to obtain:
Answers to these questions have implications for cancer prevention and early detection, cancer services planning, compensation, and estimation of the cancer burden due to the effects of chrysotile exposure worldwide. This is particularly important given the prolonged disease burden from chrysotile, which arises for two reasons: