Talc was classified as “probably carcinogenic” due in part to limited evidence linking it to ovarian cancer, an international agency said.
Talc was classified as “probably carcinogenic” to humans by the cancer agency of the World Health Organization (WHO).
A working group of 29 scientists from 13 countries met at the International Agency for Research on Cancer (IARC) in Lyon, France, and published their findings in The Lancet Oncology last week.
The classification is the “second highest level of certainty that a substance can cause cancer”. Talc’s previous classification was as a “possible carcinogen.”
Talc was classified “on the basis of a combination of limited evidence for cancer in humans (for ovarian cancer), 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 group of experts said in a press release.
Their conclusions were based on several studies showing an increased risk of ovarian cancer in women who use talcum powder in the genital area but a causal link “could not be fully established”.
Among the general population, talc is most well-known as a white baby powder, but the mineral is also a common component in makeup and skincare products.
People can also be exposed to the powder when it is mined, milled or processed or when making products out of it.
Concerns about asbestos contamination
Talc and asbestos are both naturally occurring minerals found in close proximity to the Earth.
This close association during formation can lead to contamination when the talc is mined and processed.
Asbestos is a known carcinogen when inhaled and concerns about asbestos contamination in talc products have been present since the 1970s, according to anote from the US Food and Food and Drug Administration (FDA) published in April.
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The pharmaceutical company Johnson & Johnson has been facing thousands of lawsuits in the US related to its talcum powder products and whether they are tainted with asbestos.
The new expert evaluation focused on talc that does not contain asbestos, the IARC statement read, however, “contamination of talc with asbestos could not be excluded in most of the studies”.
‘Lot of uncertainty here’
Kevin McConway, emeritus professor of applied statistics at the Open University in the UK said in a statement published by the Science Media Centre that when IARC classifies a substance in this series of publications, it does not say anything specifically about whether exposure to the substance does increase the risk of cancer, in humans.
“Instead they aim to answer the question of whether the substance has the potential to cause cancer, under some conditions that IARC do not specify,” he said, adding that “there isn’t a smoking gun that the talc use causes any increased cancer risk”.
Another expert said that even if the observed link were causal, the associated risk would be very small.