The society explains that the possible link between talcum-based powder and cancer is mixed, adding that many studies have found "a small increase in risk" but such can not be relied upon, as they are based on a person's memory on how long they have used the powder.
Healthcare giant Johnson & Johnson faces almost 17,000 lawsuits alleging that asbestos-contaminated talc-based personal care products have caused ovarian cancer and other malignant diseases in women.
The researchers found 61 cases of ovarian cancer per 100,000 people who had used the powder, versus 55 ovarian cancer cases in that same amount of people who had never used the powder. "This represents the best data we have on the topic".
Overall, the team found that women who had ever used talc for feminine hygiene during their lifetimes had an 8% increased risk of developing ovarian cancer compared with those who were not exposed.
For women who may have anxious that use of talc on their vulva has put them at increased risk of ovarian cancer, this study should provide reassurance. It could have been talcumpowder alone, cornstarch alone or a combination of both.
During a median follow-up of 11.2 years, 2,168 women developed ovarian cancer (58 cases/100,000 person-years).
But the link remained contested because of the overall low number of studies conducted, with some of them criticized for a methodology that introduced recall bias among participants, while others were not statistically conclusive.
This increase needs to be understood in context, she says. Given the difficulty in studying rarer tumors such as ovarian cancer, it is probably the most detailed data researchers will receive in the foreseeable future.
That translated to a risk difference of just 0.09% at age 70 (95% CI -0.02% to 0.19%), the researchers estimated.
The researchers say that "there was not a statistically significant association between self-reported use of powder in the genital area and incident ovarian cancer [diagnoses of ovarian cancer]".
In recent years, women have been taking talc manufacturers to court over concerns that using the product on the genital area could cause ovarian cancer. Women with cancer are more likely to remember or mention something that could be linked to cancer than women without, meaning these studies could have biased results. "Women who have ovarian cancer might be more likely to report something that they have heard may be a cause of ovarian cancer".
Rates of powder use have declined over the last 50 years, yet it remains a routine practice for some women, says Dr. Dana Gossett, a professor of obstetrics and gynecology at the University of California, San Francisco.
What did the study involve?
Johnson & Johnson is said to have nearly 17,000 cases on cancer incidents linked to its baby powder that is its major brand. Concerns have been raised about possible contamination of mineral talc with asbestos, a known cancer risk.
Most powder products include some mineral talc, which may be mined in the same location as asbestos.
The American Cancer Society also says that "findings have been mixed" and that, although there has been some suggestion of a possible increase in ovarian cancer risk, its bottom-line advice is: "until more information is available, people concerned about using talcumpowder may want to avoid or limit their use of consumer products that contain it". While the investigation will not eliminate the company's legal vulnerability, it could support J & J's argument that the link between talc and ovarian cancer found in some previous studies is undeniable.
The study has several limitations. The study based their results on self-reportage use, where 38 per cent said they used it in their genitals. It also included mostly white women.
"If women feel it's important to their hygiene routine to use genital powder, they should take comfort in this study and be assured they are not doing something that substantially risks harming their health", Gossett said.