Talc is a “probable human carcinogen”, included in group 2A of the IARC classification, the International Agency for Research on Cancer of the World Health Organization. Group 2A – the same, for example, as red meat, steroids and emissions from frying at high temperatures – is “the second highest level of certainty that a substance can cause cancer”, clarifies the IARC of the WHO which has communicated its new evaluations on talc and acrylonitrile. Analyses summarized in ‘The Lancet Oncology’, and which in 2025 will be described in volume 136 of the ‘IARC Monographs’.
Talc is a natural mineral that is mined in many regions of the world, IARC recalls. Exposure to this substance can occur in the professional field (during the extraction, milling or processing of the material, or during the production of products containing it), as well as in the general population through cosmetics and body powders, but to a lesser extent also through food, drugs and other consumer products. The IARC assessment, carried out by a team of 29 experts, focused on talcs that do not contain asbestos. Those that contain it remain in Group 1, the highest of the classification (“carcinogenic to humans”), while talc in general enters Group 2A, replacing the definitions “talc not containing asbestos or asbestiform fibres” and “perineal use of talc-based baby powders”, previously included in Group 2B (that of “possible carcinogens for humans”).
“After carefully reviewing the available scientific literature – explains the agency – the working group classified talc as probably carcinogenic to humans (Group 2A) based on a combination of limited evidence for cancer in humans (ovaries), sufficient evidence for cancer in experimental animals, and strong mechanistic evidence that talc exhibits key characteristics of carcinogens in human primary cells and experimental systems”. The IARC reports that “numerous studies have consistently demonstrated an increased incidence of ovarian cancer in self-reporters of perineal body powder use. Although the evaluation focused on non-asbestos talc”, the agency specifies that “in most studies it was not possible to exclude contamination of talc with asbestos”. For this reason, it specifies, “it was not possible to fully establish a causal role for talc” in the association with tumors.
As for acrylonitrile, it has been classified as “carcinogenic to humans” (group 1), based on a “sufficient level of evidence for lung cancer”, as well as “limited evidence for bladder cancer”.
Acrylonitrile is a volatile organic compound used primarily in the production of polymers with various uses, including fibers for clothing, carpets and other textiles – lists the IARC of the WHO – as well as plastics for consumer products, automotive components and construction. Occupational exposure to the substance can occur during the production of the compound and its use to obtain polymers. But acrylonitrile is also present in cigarette smoke and this – including passive smoking – is the main route of exposure for the general population. Another is air pollution.
#IARC #Talc #carcinogenic
