Study seeks to settle talc/ovarian cancer controversy
The use of talc powder in the genital area has again been linked with the development of ovarian cancer in a large study that addressed factors used to challenge earlier, similar findings.
A relationship between genital-area talc use and ovarian cancer “has been repeatedly observed but repeatedly challenged due to a ‘weak' overall association and apparent lack of dose-response,” contended an investigative team in the abstract they presented at annual meeting of the American Association for Cancer Research (AACR), held April 2-6, 2011, in Orlando, Florida.
The researchers, led by Daniel W. Cramer, MD, of Brigham and Women's Hospital in Boston, undertook their analysis to determine whether previous findings of the link between the talc and the cancer had been affected by the failure to consider, in a uniform fashion, histologic type of ovarian cancer, menopausal status, or family history. They combined data from three phases of their own case-control studies, involving a total of 2,074 ovarian cancer cases and 2,101 controls enrolled between 1992 and 2008.
After adjusting for a variety of factors, including but not limited to histologic type of cancer and family history, Cramer's group found that the use of talc raised the risk for ovarian cancer by 30% for all cases. They also found a striking difference in dose-response between premenopausal and postmenopausal women, with dose-response being more apparent among the former group and relatively flat for the latter. After cases with a possible familial disease were excluded, the dose-response in premenopausal women with invasive serous cancer odds ratios were 2.22 for about 2,000 to 8,400 applications of talc and 3.23 for women with more than 8,400 applications, compared with women who did not use talc.
“The failure to take into consideration histologic type of ovarian cancer in a systematic fashion has led to both an underestimation of the overall effect in all women and the dose-response in premenopausal women, especially those without a family history,” concluded the researchers. “Repeating analyses in existing data sets may help clarify the still-debated association between talc and ovarian cancer.”