The Sister Study, conducted from 2003-2009 with the support of the National Institutes of Health, National Institute of Environmental Health Sciences was a landmark research effort to find the causes of breast cancer. The study also included an analysis among participants to investigate associations between talc use, douching and ovarian cancer.
The study enrolled 41,654 women in the United States and Puerto Rico aged 35 to 74 years who had a full or half sister who had been diagnosed with breast cancer and were asked about talc use over the prior 12 months. Over the course of the study, no association was found between perineal talc use and subsequent diagnosis of ovarian cancer.7 While douching was more common among talc users, it was found that douching, but not talc, was associated with the increased risk of ovarian cancer during the Sister Study.7