This week, a jury in St. Louis ordered Johnson & Johnson to pay $72 million in damages to the family of a woman who died from ovarian cancer at age 62 and was a long-time user of the company's talc powder products, as reported by Medscape Medical News .
The jury found Johnson & Johnson guilty of negligence, failure to warn, and conspiracy to conceal the potential risks of its talcum powder products, according to news reports.
So laypeople have spoken. But what do studies and researchers say about the possible risk of developing ovarian cancer from using talc powder in the genital/rectal area for "feminine hygiene"?
A review by Medscape Medical News found that the literature has mixed results, and that experts have conflicting interpretations of that evidence.
The fact that talc is even being questioned as an ovarian cancer risk may surprise some professionals, said Daniel Cramer, MD, ScD, an obstetrician/gynecologist at Brigham and Women's Hospital and Harvard Medical School in Boston and a prominent researcher in this field.
"Some clinicians — even some gynaecologists — will never have heard of this association," he told Medscape Medical News. "I've had clinicians say to me, 'Talc? Do they still sell it?'"
Talc is a cause of ovarian cancer, says Dr Cramer, who was the lead author of the first study ever to link talc use with ovarian cancer in 1982 and who also testified at the Johnson & Johnson trial as a paid expert witness.
He cited 20 well-executed, case-control studies that support the association over the last 30 years, including a recent study he coauthored, which was published just a few months ago (Epidemiology. Published online December 17, 2015).
There is about 30% increased risk for ovarian cancer with talc usage in the case-control studies, on average, and there is evidence of a dose-response relationship in some studies, he said.
Karin Rosenblatt, PhD, a professor of public health at the University of Illinois at Urbana-Champaign, also estimates the increased risk to be roughly 30% and agrees about the dose-response evidence, which is part of the basis of causal relationships.
However, Dr Rosenblatt, who was also the lead author of a case-control study that found a positive association (Cancer Causes Control. 2011;22:737-742), is uncertain of the data's meaning.
"I can't say for sure if [talc] is a definite risk," said Dr Rosenblatt, who has no ties to industry, in an interview with Medscape Medical News.
Likewise, major cancer organizations are not definite.
For example, the International Agency for Research on Cancer (IARC) said categorized talc is "possibly" carcinogenic to humans and an American Cancer Society (ACS) report from 2014 calls for more research and says "if there is an increased risk, the overall increase is likely to be very small."
The ACS says anyone concerned about using talc could instead use cornstarch-based powder products.
The argument for talc carcinogenicity hinges on case-control study evidence. But this type of research may be vulnerable to recall bias (if women with ovarian cancer were more likely to overreport talc use), said the IARC in its 2006 report.
Dr Cramer feels that this criticism is overblown, given the large body of case-control evidence: "To attribute all of the case-control associations to recall bias is simply ludicrous."
However, the case for talc as a risk factor was dealt two other big blows in the last 15 years, according to Robert Coleman, MD, a gynecologic oncologist at the University of Texas MD Anderson Cancer Center in Houston, who has been a paid consultant to Johnson & Johnson.
Two prospective, cohort studies were published during that time, using data from the Nurse's Health Study and the Women's Health Initiative (WHI), respectively. Both studies showed no association between talc use and an overall increased risk for ovarian cancer (J Natl Cancer Inst. 2000; 92: 249−52 and J Natl Cancer Inst. 2014;106).
These prospective cohort studies are more authoritative than case-control studies, which are retrospective, Dr Coleman told Medscape Medical News.
The talc-ovarian cancer link is "dogma" that has now mostly been "disproved by better science," summarized Dr Coleman.
However, other experts have pointed out that the cohort findings from the WHI and the Nurse's Health Study have significant limitations that weaken their value.
In a 2014 editorial, Nicolas Wentzensen, MD, PhD, and Sholom Wacholder, PhD, both from the National Cancer Institute, pointed out that the WHI investigators only collected information on the duration of use — not on frequency. And that the Nurses' Health Study only collected information on frequency of use — and not duration.
Neither study provides a sufficient assessment of talc exposure, they said.
Overall, the evidence about talc carcinogenicity is "inconclusive," summarized the editorialists.
They write: "While reporting bias may explain the positive associations reported from case-control studies, the limitations of the cohort studies regarding exposure assessment still do not completely eliminate the possibility that talc use is associated with ovarian cancer risk," they write.
In other words, talc use might be a risk and it might not, they said.
Notably, the Nurse's Health Study did show that talc use was associated with an increased risk for serous ovarian cancer, the most lethal and common subtype (but showed no association with ovarian cancer overall, as noted above).
How Could Talc Cause Ovarian Cancer?
Johnson & Johnson argues that talc powder is safe. After the jury's decision this week, spokesperson Carol Goodrich said, "We sympathize with the plaintiff's family but firmly believe the safety of cosmetic talc is supported by decades of scientific evidence." The company is expected to appeal the ruling.
The biological basis of the possible carcinogenicity of talc, which is the softest of all minerals, is often cited as chronic inflammation of the ovarian epithelium, caused by contact with talc particles.
Talc is often applied in the genital/anal area, including on sanitary napkins, tampons, and underwear, Dr Cramer explained.
Very small particles comparable in size to talc have been shown to migrate from the vagina to the upper pelvic tract, he says. In addition to traveling to the ovaries, talc has also been found in pelvic lymph nodes (Obstet Gynecol. 2007;110:498-501).
Jackie Fox, whose ovarian cancer prompted the court case in St Louis, had talc found in her surgically removed ovaries, according to news reports.
The evidence that talc can migrate to the ovaries dates back to at least 1971, when British surgeons reported a study that found 10 of 13 ovarian and cervical tumors had "talc particles deeply embedded" in the tumor tissue.
Talc naturally co-occurs with asbestos, and it was theorized in the past that asbestos contamination of talc may have been the cause of any increased risk for ovarian cancer. However, talc powders in the United States became asbestos-free in the 1970s, and yet case-control studies after that time have continued to show an association with ovarian cancer.
Talc use substantially decreased in the United States between 1982 and 2004, according to NCI's Dr Wentzensen and Dr Wacholder.
But Dr Cramer said that change is mostly meaningless if you consider that plenty of women still use talc in the genital area. "If you had a modifiable exposure, why wouldn't you want to advise women about it?" he asked.
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Cite this: Talc Powder, Ovarian Cancer Link: What is the Evidence? - Medscape - Feb 25, 2016.
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