Women have used powders for genital hygiene for decades to absorb odors and moisture. While rates of powder use in the genital area have declined over the past 50 years, it remains a routine practice for some women. Commonly used products typically include talc, cornstarch, or a combination of both. Investigations into an association between the use of talc-containing powders for genital hygiene and ovarian cancer have revealed mixed results. Recent high-profile litigation and media coverage of the risk of ovarian cancer among users of talc products prompted the National Institute of Environmental Health Sciences (NIEHS) to conduct a large study to determine whether a link between the two actually exists. The results of that study were published early this year.
Talc, like asbestos, is a soft mineral and has a chemical structure similar to asbestos. Both minerals are often found in the same mines. Asbestos, of course, is a known carcinogen. All U.S.-based manufacturers of cosmetic talc agreed to ban asbestos from their products in 1976, and the International Agency for Research on Cancer has since concluded that there is only “possible” evidence that genital use of talc powders may be carcinogenic. The theory is that when applied to a woman’s genital area, talc may enter the vagina and be transported through the uterus and fallopian tubes to the ovaries where it causes an inflammatory reaction, which eventually causes cancer.
The NIEHS study collected data from four large cohort studies, namely the Nurses’ Health Study, the Nurses’ Health Study II, the Sister Study, and the Women’s Health Initiative Observational Study. In all, there were more than 250,000 participants. It divided participants into two groups: never users and ever users (ever users being those who reported using talc powder at least once). Ever users were then subdivided into long-term users, infrequent users, and past users. Participants were asked to define their use of talc going back more than 20 years. Additional data was collected, including age, race, education history, body-mass index, parity (number of pregnancies and births), smoking history, oral contraceptive use, hormone therapy use, tubal ligation and gynecologic surgery history, and menopausal status.
In this large U.S. study, there were no statistically significant association between self-reported use of powder in the genital area and ovarian cancer. There was also no clear dose-response trends for duration and frequency of powder use in the genital area and ovarian cancer risk. This is the first major U.S. study to clearly show no association between talc powder use and ovarian cancer.
As previously noted, the theory was that talc causes inflammation which leads to cancer. This is based on the known fact that pelvic inflammatory disease (serious gynecologic infection) and chlamydial infections cause inflammation that increases the risk of ovarian cancer, while the use of aspirin, which reduces inflammation, reduces the risk of ovarian cancer. The authors concluded that prior studies that showed a possible link between talc and ovarian cancer may have been tainted by recall bias (participants either over or underestimated their use of talc products), making the study results inaccurate or unreliable.
By Peter Galvin, MDBLOG COMMENTS POWERED BY DISQUS