Cosmetic talc should not be listed as a carcinogen: comments on NTP's deliberations to list talc as a carcinogen

Our plain-English summary of Cosmetic talc should not be listed as a carcinogen: comments on NTP's deliberations to list talc as a carcinogen, by A.P. Wehner (Regulatory Toxicology and Pharmacology, 2002).

The study

• Author: A.P. Wehner
• Journal: Regulatory Toxicology and Pharmacology
• Published: 2002;36(1):40-50
• Type of article: Review
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Concerns that cosmetic talc might be carcinogenic are addressed and shown to lack persuasive scientific support. These concerns are based (1). on several, but not all, retrospective epidemiological, statistically barely significant case-control studies of questionable biological import (Their results lack dose-response relationships, are inconsistent and ambiguous, and are therefore inconclusive. Whether inanimate talc particles can translocate from the perineum to the ovaries, a precondition if they were to cause ovarian cancer, remains unresolved.); (2). on one inhalation study in animals whose results, according to a panel of experts, "cannot be considered as relevant predictors of human risk," a position shared by other experts in the field; and (3). on elevated incidence of lung cancer in pottery workers. These workers were occupationally exposed several decades ago to nowadays impermissible concentrations of aerosols comprising a multitude of industrial dusts. To construe a risk for the consumer of pure cosmetic or pharmaceutical-grade talc under consumer conditions, based on these findings, lacks scientific support. Talc is not genotoxic, is not carcinogenic when injected into ovaries of rats, does not cause cancer decades after pleurodesis, and induces apoptosis in vitro in human mesothelioma cells but not in normal mesothelial cells. There is no credible evidence of a cancer risk from inhalation of cosmetic talc by humans. Considering talc a carcinogen lacks convincing scientific documentation.

In plain English

This review and commentary, not new research, responded to the National Toxicology Program's (NTP) consideration of listing talc as a carcinogen. The author examined NTP's three reasons: a rodent inhalation study, ovarian cancer studies of genital talc use, and lung cancer in pottery workers. The NTP study found more lung cancer only in female rats at the highest dose (18 mg/m3); the author attributed this to lung overload. Of 21 case-control studies of ovarian cancer, 15 showed a weak, barely significant link; 6 did not. A prospective study of 78,630 nurses found no overall association (RR = 1.09; 95% CI, 0.86–1.37). Only when cancers were split by type did a barely significant increase appear, for serous invasive cancers with ever talc use (RR = 1.40; 95% CI, 1.02–1.91), not other types. The author argued the talc and pottery workers cited were exposed to mixed dusts, in one group including tremolite and serpentine, while pure-talc workers showed no significant increase in lung cancer mortality. The author concluded evidence for a causal link between cosmetic talc and cancer is insufficient.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review and commentary on the evidence NTP cited for listing talc as a carcinogen; no new data
• Who was studied: Published studies cited by the author: the NTP rat and mouse inhalation study, 21 case-control studies of talc use and ovarian cancer, a prospective cohort study, particle translocation studies, and studies of talc and pottery workers
• Exposure: Cosmetic talc, described by the author as nonasbestiform: perineal (genital) use and inhalation. Also occupational exposure of talc and pottery workers to industrial talc and mixed dusts.
• Main results:
  • In the NTP inhalation study, as summarized by the author, lung cancer incidence was significantly higher only in female rats of the 18 mg/m3 group, not in any other group
  • The author argued that the NTP aerosol concentrations and exposure times were too high, causing lung overload
  • Of 21 case-control studies of talc use and ovarian cancer, 15 showed a weak, barely statistically significant link and 6 did not
  • The Gertig et al. prospective Nurses' Health Study, as described by the author, analyzed a cohort of 78,630 women
  • In the Gertig et al. cohort, ever use of talc was not associated with ovarian cancer overall (RR = 1.09; 95% CI, 0.86–1.37)
  • In the Gertig et al. cohort, only when cancers were stratified by histological subtype was a barely statistically significant increase seen for ever talc use, for serous invasive cancers (RR = 1.40; 95% CI, 1.02–1.91). The increase was not seen for all serous cancers (including borderline), endometrial (printed 'endometrial') cancers, or mucinous cancers.
  • An earlier life span inhalation study of cosmetic talc in hamsters (Wehner et al., 1977a) produced no tumors
  • In a study of talc placed in the vaginas of cynomolgus monkeys (Wehner et al., 1986), talc was found only at the site of deposition
  • Talc workers studied by Kleinfeld et al. in New York state were exposed to dusts containing other silicates, including serpentine, tremolite and anthophyllate (as printed)
  • According to the cited studies, talc workers exposed to pure talc did not show significant increases in lung cancer mortality
  • In patients treated with talc pleurodesis (Chappell et al., 1979), no mesothelioma was found in 199 traceable patients 14 to 40 years later
• The authors' conclusion: The author concluded that there is insufficient experimental and epidemiological evidence for a causal association between cosmetic talc and cancer in animals or humans

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Cosmetic Talc, Talc, Carcinogenic, Dose-response relationship, Ovarian Cancer, Lung Cancer, Pleurodesis, Apoptosis.

Related studies

• Cosmetic talc and ovarian cancer — D.L. Longo, R.C. Young (1979)
• A quantitative weight of evidence assessment of Hill's guidelines for causal inference for cosmetic talc as a cause of mesothelioma — A.M. Ierardi, A. Urban, et al. (2021)
• Amphibole content of cosmetic and pharmaceutical talcs — A.M. Blount (1991)
• Effect of exposure route on potency of carcinogens — W.E. Pepelko (1991)
• Detection of aneuploidy-inducing carcinogens in the Syrian hamster embryo (SHE) cell transformation assay — D.P. Gibson, M.J. Aardema, et al. (1995)
• A randomized controlled trial of the efficacy of cosmetic talc compared with iodopovidone for chemical pleurodesis — R. Agarwal, A.S. Paul, et al. (2011)

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