WHO agency says talc is ‘probably’ cancer-causing

Lyon – The World Health Organisation’s (WHO) cancer agency on July 5 classified talc as “probably carcinogenic” for humans. However, an outside expert warned against misinterpreting the announcement as a “smoking gun”.

The decision was based on “limited evidence” that talc could cause ovarian cancer in humans, “sufficient evidence” that it was linked to cancer in rats, and “strong mechanistic evidence” that it shows carcinogenic signs in human cells, said the WHO’s International Agency for Research on Cancer (IARC).

Talc is a naturally occurring mineral mined in many parts of the world and is often used to make talcum baby powder.

Most people are exposed to talc in the form of baby powder or cosmetics, according to the Lyon-based IARC.

But the most significant exposure to talc occurs when it is being mined, processed or used to make products, it added.

The agency said there were numerous studies which consistently showed an increase in the rate of ovarian cancer in women who use talc on their genitals.

But it could not rule out that the talc in some studies was contaminated with cancer-causing asbestos.

“A causal role for talc could not be fully established”, according to the agency’s findings published in The Lancet Oncology.

Mr Kevin McConway, a statistician at Britain’s Open University who is not involved in the research, warned that for the IARC’s evaluation, the “most obvious interpretation is actually misleading”.

The agency is aiming only “to answer the question of whether the substance has the potential to cause cancer, under some conditions that IARC do not specify”, he said.

Because the studies were observational and so could not prove causation, “there isn’t a smoking gun that the talc use causes any increased cancer risk”, he added.

The announcement comes just weeks after US pharmaceutical and cosmetics giant Johnson & Johnson

agreed to pay US$700 million (S$944 million) to settle allegations

it misled customers about the safety of its talcum-based powder products.

Johnson & Johnson did not admit wrongdoing in its settlement, even though it withdrew the product from the North American market in 2020.

A summary of studies published in 2020 covering 250,000 women in the United States did not find a statistical link between the use of talc on the genitals and the risk of ovarian cancer.

Also on July 5, the IARC classified acrylonitrile, a chemical compound used to make polymers, as “carcinogenic to humans”, its highest warning level.

It cited “sufficient evidence” linking acrylonitrile to lung cancer.

The polymers made with acrylonitrile are used in everything from fibres in clothes to carpets, plastics and other consumer products. AFP