Scientists: Facts Fail to Support Some Conclusions in JAMA Article on Talc Use, Ovarian Cancer

SEATTLE, Jan. 8, 2020 /PRNewswire/ -- A recently released article in the Journal of the American Medical Association examining the link between genital talcum powder use and ovarian cancer relied on large-scale studies that were not designed to adequately answer that question, according to clinical researchers who have examined the data.

"This article is an update of previously published cohort studies which didn't collect information on lifetime use," said Dr. Anne McTiernan, an epidemiologist and researcher at the Fred Hutchinson Cancer Center in Seattle and Professor at the University of Washington School of Medicine. "Because of this, the risks from talcum powder exposure seen in this paper are likely underestimates of their true size."

Dr. McTiernan and other clinicians point out, and the JAMA authors acknowledge, that there are limitations with the cohort studies.  For example, in the studies, the "specific exposure windows could not be examined, nor could type of powder used or patency status at time of powder use." 

Even with those limitations, the JAMA study found a heightened risk among certain women who used the products. The data showed that women who had used talcum powder products in the genital area at some time in their lives had an 8 percent increased risk of developing ovarian cancer. In addition, women who used baby powder and never had a hysterectomy or a tubal ligation procedure had a 13 percent higher risk of developing ovarian cancer compared to women who never used the product.

That risk rose to 19 percent among women who used baby powders at least once a week. For frequent users who had epithelial ovarian cancer, the group that most resembles plaintiffs in litigation who used the talcum powder on a daily basis for an extended period of time, the study demonstrated an increased risk of 21 percent.

"This was the largest study ever done, but because ovarian cancer is such a rare disease, it was still not big enough to detect a very small change in risk," said Katie O'Brien, an NIEHS epidemiologist who led the study, quoted in a Reuters article. Overall, "it is not great data," she said.

However, the study does support other research which has found that talc particles can migrate into the ovaries, causing inflammation and leading to the growth of malignant cells. The JAMA authors observed that talcum powder "could irritate and inflame the reproductive tract and "set off a cascade of increased oxidative stress levels, DNA damage, and cell division, all of which could contribute to carcinogenesis."  

The racial and physical characteristics of participants in the cohort studies relied on by the JAMA article also call some of the study's conclusions into question. While those participants were overwhelmingly young, Caucasian and within healthy weight ranges, baby powder users are disproportionally older African-Americans with body weights that fall within obesity standards. Evidence presented at trials points out that Johnson & Johnson has recognized these demographics from a marketing perspective and marketed directly to this minority population for generations.

The original studies used by JAMA also did not collect detailed information on what types or brands of powder products women used.

"They don't know if they used powder with talc or if they used corn starch," said David Egilman, a clinical professor of family medicine at Brown University in a Bloomberg article about the study. That article notes that talc use may also cause ovarian cancer through inhalation through the lungs, a type of exposure that was not addressed by the JAMA study.

For decades, dozens of case-control studies have examined the link between genital talc use and ovarian cancer, consistently finding a 30 percent increase in ovarian cancer among women who used talcum powder for feminine hygiene. Such studies are generally recognized as being more accurate in detecting association for comparably rare diseases such as ovarian cancer.

Both Dr. McTiernan and Dr. Egilman have been compensated for serving as scientific experts on behalf of plaintiffs, some of whom are represented by Beasley Allen law firm, who have sued talcum powder makers.

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SOURCE Beasley Allen