Study Finds No Association Between Powder Use and Ovarian Cancer

An analysis of 4 US cohorts showed no statistically significant association between use of powder in the genital area and incidence of ovarian cancer, according to a study published in JAMA.¹

The study analyzed data from a total of 252,745 women with a median age at baseline of 57 years. Thirty-eight percent self-reported using powder in the genital area, with 10% reporting long-term use and 22% reporting frequent use. Median follow-up was 11.2 years, with a total of 2168 women developing ovarian cancer during that time. Ovarian cancer incidence for talc users was 61 cases of 100,000 person-years, with an incidence of 55 cases of 100,000 among the never users (estimated risk difference at age 70 years, 0.09%; 95% CI, −0.02%-0.19%; estimated HR, 1.08; 95% CI, 0.99-1.17).

The estimated HR for long-term use vs never use was 1.01 (95% CI, 0.82-1.25), with an estimated HR of 1.09 (95% CI, 0.97-1.23) for frequent vs never users.

“There were no clear dose-response trends for duration and frequency of powder use in the genital area in relation to ovarian cancer risk,” said the researchers. “Although the study was underpowered to detect small changes in risk, this is, to our knowledge, the largest study of this topic to date.”

With several peer-reviewed articles documenting a possible association between talc use and ovarian cancer, and recent litigation regarding the risks of ovarian cancer for talc users, the researchers were prompted to look at a larger study population in order to further investigate any link between powder use and ovarian cancer.²

Data was pooled from the Nurses’ Health Study (NHS, n = 81,869), Nurses’ Health Study II (NHSII, n = 61,261), Sister Study (SIS, n = 40,647) and the Women’s Health Initiative Observational Study (WHI-OS, n = 73,267). Exposures were defined as ever, long-term (≥20 years) and frequent (≥1/week). Long-term use was reported by 16% in WHI-OS, and by 6% in both SIS and NHSII, with frequent use at 27% in NHS, 26% in NHSII, and 7% in SIS.

“The study by O’Brien et al represents the largest cohort to date to examine whether an association exists between powder use in the genital area and ovarian cancer risk, and the findings are overall reassuring,” wrote Dana R. Gossett, MD MSCI of the Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California-San Francisco, in an accompanying editorial. “The rigorously conducted study contributes important and timely data about the potential link between use of powder in the genital area and risk of ovarian cancer.”

The authors also performed an exploratory analysis to examine if the risk associated with powder use varied by subgroup, including age, race/ethnicity, BMI, and patency. HRs for all groups were comparable. While one subgroup analysis of did show some positive association for women with intact reproductive tracts, Gossett noted that the data is “below the effect size that epidemiologists generally consider important and should not be selectively highlighted by the statistically unsophisticated reader as evidence of a relationship.”

References:

1. O’Brien KM, Tworoger SS, Harris HR, et al. Association of Powder Use in the Genital Area With Risk of Ovarian Cancer. JAMA. 2020;323(1):49-59. doi:10.1001/jama.2019.20079

2. Gossett DR, del Carmen, MG. Use of Powder in the Genital Area and Ovarian Cancer Risk: Examining the Evidence. JAMA. 2020;323(1):29-31.