Systematic review of the association between talc and female reproductive tract cancers

Abstract

Talc is a hydrous magnesium sheet silicate used in cosmetic powders, ceramics, paints, rubber, and many other products. We conducted a systematic review of the potential carcinogenicity of genitally applied talc in humans. Our systematic review methods adhere to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and incorporated aspects from the US Institute of Medicine (IOM, now the National Academy of Medicine) and several US EPA frameworks for systematic reviews, evaluating and integrating the epidemiological, animal, and mechanistic literature on talc and cancer. We conducted a comprehensive literature search. Detailed data abstraction and study quality evaluation, adapting the Toxic Substances Control Act (TSCA) framework, were central to our analysis. The literature search and selection process identified 40 primary studies that assessed exposure to talc and female reproductive cancer risks in humans (n = 36) and animals (n = 4). The results of our evaluation emphasize the importance of considering biological plausibility and study quality in systematic review. Integrating all streams of evidence according to the IOM framework yielded classifications of suggestive evidence of no association between perineal application of talcum powders and risk of ovarian cancer at human-relevant exposure levels. We also concluded that there is suggestive evidence of no association between genital talc application and endometrial cancer, and insufficient evidence to determine whether a causal association exists between genital talc application and cervical cancer based on a smaller but largely null body of literature.

Quantitative recall bias analysis of the talc and ovarian cancer association

“…This was motivated by reviews and meta-analyses reporting different results by study design ( e.g. , [ [7] , [8] ]) and the recent availability of data on talc recall in the prospective Sister's Study [ 13 ]. Realistically, the impact of all sources of bias and confounding are likely complex.…”

“…Cohort studies have consistently reported no overall association and no exposure-response relationship between perineal talc use and ovarian cancer risk overall. Also, experimental studies do not support a causal association [ 7 , 28 ]. Our analysis, using data from the Cramer et al [ 15 ] case-control study, demonstrates that recall bias alone may have a large impact on risk estimates.…”

“…It has been shown in several reviews and meta-analyses that, while case-control studies generally report small positive associations, the results of cohort studies examining talc use and ovarian cancer overall are consistently null [ [1] , [2] , [3] , [4] , [5] , [6] ]. For example, Lynch et al [ 7 ] noted, “None of the five prospective cohort studies reported any statistically significant associations between genital talcum powder use and risk of epithelial ovarian cancer, and relative risk estimates were close to unity.” They added, “ Of the 26 case-control studies evaluated, 18 (69%) reported at least one statistically significant odds ratio for ovarian cancer and genital talcum powder use” [ 7 ].…”

“…Meta-analyses of these studies, driven by the case-control studies' results, have frequently reported a small but statistically significant increase in ovarian cancer risk associated with talc use ( e.g. , [ [7] , [8] ]). For example, Penninkilampi and Eslick [ 8 ] reported a meta odds ratio (OR) of 1.35 (95% confidence interval [CI]: 1.27–1.43) for case-control studies, 1.06 (95% CI: 0.90–1.25) for cohort studies, and 1.31 (95% CI: 1.24–1.39) overall.…”

Banning asbestos in talcum powder: Time for action in India

“…Nevertheless, some studies support an opposing perspective [ 37 , 38 , 39 , 40 ]. While certain studies have explored the link between talc exposure and ovarian cancer [ 30 , 41 ], there has been insufficient research on the tissue specific effects on the female genital system. In particular, the molecular and genetic processes associated with exposure to a cosmetic ingredient and the initial stages of cancer development have not been thoroughly investigated.…”