The study, one of the largest on this subject to date, published Tuesday in the medical journal JAMA. It was found that there was no statistically significant association between the use of genital talc and ovarian cancer. However, the study notes that it may have had "little power" to identify a small increase in risk, in part because there were not many cases of ovarian cancer among the women studied.
The researchers reached this conclusion by looking at a large number of patients, using pooled data of 252,745 American women with an average age of 57 years. Of those women, 38% said they used dust in their genital area, 10% said they had been doing so for at least 20 years and 22% said they used it at least once a week.
After approximately 11 years, 2,168 had developed ovarian cancer. That was broken down into 61 cases per 100,000 people a year among those who once used talc around their genital areas and 55 cases per 100,000 years per person among those who did not.
The study says there is a possible association between dust and ovarian cancer among women who had no history of hysterectomy or tubal ligation, but this "finding should be considered only exploratory and hypothesis-generating." If future research shows this association, there could be some truth in the hypothesis that dust can irritate or inflame the reproductive tract. There is a relationship between pelvic inflammatory disease and ovarian cancer, but more research is needed to draw any conclusions about this possible connection.
This observational study has limitations. The way in which the groups evaluated the exposure and the frequency of use varied, so it is difficult to know if there is a connection with the amount of a person using the powder and ovarian cancer. The data did not capture what types of powders women used. The four datasets mainly included white and well-educated women, half of whom had a BMI below 25, which means they were not overweight, so it is not clear if this result can be generalized to other demographic data.
"One thing that this research clearly demonstrates is how difficult it is to determine if something like this is indeed a risk factor for cancer. Despite being a good, competent and careful study that involves more than a quarter of a million women, it still leaves room for doubt about the association, if there is one, between the use of dust in the genital area and ovarian cancer, "said Kevin McConway, emeritus professor of applied statistics at the Open University, in a Science statement Media Center in the United Kingdom.
"There is still uncertainty about whether there is such an association. If there is, there is uncertainty about whether it is the dust itself that causes some increase in cancer risk. And there is also uncertainty about the size of the increased risk, if it exists, there is one, "adds McConway. "But what the research states, I would say, is that if the use of talc or other powder on that part of a woman's body really increases the risk of ovarian cancer, the risk increase is likely to be small. I am not a woman, so I cannot have concerns about my own health in these aspects, but if I were a woman, this would not be on my list of concerns. "
Concerns about a link between talc and ovarian cancer began to arise around 1971, when a small group of scientists wrote about finding talcum particles deeply embedded in ovarian and cervical tumor tissue. The study concluded that it is "impossible to incriminate talc as the main cause of carcinomatous changes," based solely on what was described in the study; however, "the possibility that talcum is related to other predisposing factors should not be ruled out."
Studies over the years have shown mixed results. Some studies reviews show a moderate risk. Some show that "it does not seem to influence cancer risk." Most are population-based studies and cannot prove a direct cause and effect relationship.
In general, the causes of cancer are difficult to prove, since cancer takes time to develop and can be influenced by a wide variety of factors.
In 2006, the International Agency for Research on Cancer, which belongs to the World Health Organization, classified the use of talc in the genital area as "possibly carcinogenic to humans", but this is considered its weakest classification as a cause of cancer, which means that the evidence is not entirely clear.
The American Cancer Society also says that talc's relationship with cancer "is less clear" and that "the results have been mixed." He adds that "although there is some suggestion of a possible increase in the risk of ovarian cancer," his final advice is, "until more information is available, people concerned with the use of talc may wish to avoid or limit the use of products of consumption". that contain it. "