http://www.ncbi.nlm.nih.gov/pubmed/26689397
“Multiple studies of ovarian cancer and genital talc use have led only to consensus about possible carcinogenicity. Seeking greater clarity, we examined this association in 2041 cases with epithelial ovarian cancer and 2100 age-and-residence-matched controls.
METHODS:
We defined genital talc use as regular application to the genital/rectal area directly, on sanitary napkins, tampons, or underwear. To estimate “talc-years”, we multiplied applications-per year by yearsused

Overall, genital talc use was associated with an OR (95% CI) of 1.33(1.16, 1.52) with a trend for increasing risk by talc-years. Women who used talc were more likely to be: older, heavier, asthma sufferers, and regular analgesic users-none of which were confounders.”

http://jnci.oxfordjournals.org/content/106/9/dju260.long
2014 Journal national cancer institute editorial
“Ample epidemiologic evidence suggesting that inflammation plays an important role in ovarian carcinogenesis include associations of incessant ovulation, endometriosis, and pelvic inflammatory disease with increased ovarian cancer risk (3) and reduced risks observed for regular aspirin users (4).
Evidence on perineal talc use as a risk factor for ovarian cancer is more equivocal. Talc, a metamorphic mineral composed of magnesium silicate that absorbs water, is a common component of genital powders.
2006 the International Agency for Research on Cancer (IARC) classified genital talc use as possibly carcinogenic to humans (carcinogen group 2B) (14)
How do the results from Houghton et al. (7) change the assessment of harm related to perineal talc use? Overall, the evidence regarding carcinogenicity of talc use remains inconclusive. While reporting bias may explain the positive associations reported from case-control studies, the limitations of cohort studies regarding exposure assessment still do not completely eliminate the possibility that talc use is associated with ovarian cancer risk. So where do we go from here? Ideally, we would want to have high-quality exposure data on talc use in a cohort setting, with periodic updates on exposure. These data are currently not available. Ovarian cancer is rare, and collecting these data prospectively will take time.

Research in same issue
http://jnci.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=25214560
Perineal powder use was assessed at baseline by self-report regarding application to genitals, sanitary napkins, or diaphragms and duration of use. The primary outcome was self-reported ovarian cancer centrally adjudicated by physicians

Among 61576 postmenopausal women, followed for a mean of 12.4 years without a history of cancer or bilateral oophorectomy, 52.6% reported ever using perineal powder. Ever use of perineal powder (hazard ratio [HR]adj = 1.06, 95% confidence interval [CI] = 0.87 to 1.28) was not associated with risk of ovarian cancer compared with never use. Individually, ever use of powder on the genitals (HRadj = 1.12, 95% CI = 0.92 to 1.36), sanitary napkins (HRadj = 0.95, 95% CI = 0.76 to 1.20), or diaphragms (HRadj = 0.92, 95% CI = 0.68 to 1.23) was not associated with risk of ovarian cancer compared with never use, nor were there associations with increasing durations of use. Estimates did not differ when stratified by age or tubal ligation status.
Conclusion Based on our results, perineal powder use does not appear to influence ovarian cancer risk.

second cohort study 1999, 20 years
http://jnci.oxfordjournals.org/content/92/3/249.full

The Nurses’ Health Study is a prospective study of 121 700 female registered nurse
There was a modest elevation in risk for ever talc use and invasive serous ovarian cancer (multivariate RR = 1.40; 95% CI= 1.02-1.91). The risk of epithelial ovarian cancer for talc users was not greater among women who had never had a tubal ligation (multivariate RR = 0.97; 95% CI= 0.71-1.32). CONCLUSION: Our results provide little support for any substantial association between perineal talc use and ovarian cancer risk overall; however, perineal talc use may modestly increase the risk of invasive serous ovarian cancer.
http://link.springer.com/article/10.1007%2Fs10552-011-9894-5
ANECS was a population-based case–control study conducted from 2005 to 2007, in which 1,399 women with newly diagnosed histologically confirmed primary endometrial cancer and 740 control women provided risk factor information via telephone interview
The absence of any increase in risk and the similarity of our results for talc use on the upper body and in the perineal area do not support the hypothesis that use of talc in the perineal area is associated with an increased risk of endometrial cancer. Our data do not confirm the positive association between perineal talc use and endometrial cancer observed in the only previous study.
2008 review euripean journal of cancer
ihttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621109/
Talc, like asbestos, is a silicate that has been studied in relation to cancer risk. Several studies conducted over the past 25 years found an association between perineal talc powders and ovarian cancer. The summary relative risk is about 1.3 (95 percent confidence intervals 1.2–1.5) and these data have been interpreted as supporting a causal role.
Perhaps more importantly, whereas it is unknown whether external talc dust enters the female reproductive tract, measures of internal talc exposure such as talc-dusted diaphragms and latex condoms show no relationship with ovarian cancer risk. In addition, the therapeutic use of high dose cosmetic grade talc for pleurodesis has not been shown to cause cancer in patients receiving these treatment modalities. Talc is not genotoxic. Mechanistic, pathology and animal model studies have not found evidence for a carcinogenic effect. In summary, these data collectively do not indicate that cosmetic talc causes ovarian cancer.

Complaint that J +J baby talc “
The suit says J&J has long marketed Johnson’s Baby Powder to women as a way to “maintain freshness and cleanliness,” encouraging them to dust with it daily to mask odors.
The complaint does not delineate a specific class period but says the company has known that research dating to 1961 has shown that particles of talc, similar in composition to asbestos, “can translocate from the exterior genital area to the ovaries of women.”
http://blog.thomsonreuters.com/index.php/johnson-johnson-hides-baby-powders-link-to-cancer-suit-says/
“A jury here has awarded $72 million in damages on a woman’s claim that her longtime use of baby powder and other Johnson & Johnson products contributed to the ovarian cancer that killed her.
The St. Louis Circuit Court jury found that the company failed to warn the public and conspired to hide the truth, said Jim Onder, one of the lead attorneys, who practices in Webster Groves.
Johnson & Johnson, a health care giant based in New Brunswick, N.J., is expected to appeal. It issued a statement Tuesday insisting the products are safe.
The plaintiffs’ lawyers said it was the first jury in the nation to award damages over claims that are the basis of suits by at least 1,200 women here and elsewhere.”
http://www.stltoday.com/news/local/crime-and-courts/jury-orders-johnson-johnson-to-pay-million-in-talcum-powder/article_26e6046c-f97d-5a6d-a879-a97535dd78bc.html

US pooled analysishttp://cancerpreventionresearch.aacrjournals.org/content/early/2013/06/12/1940-6207.CAPR-13-0037.abstract
Genital powder use was associated with a modest increased risk of epithelial ovarian cancer (odds ratio 1.24, 95% confidence interval 1.15-1.33) relative to women who never used powder. Risk was elevated for invasive serous (1.20, 1.09-1.32), endometrioid (1.22, 1.04-1.43), and clear cell (1.24, 1.01-1.52) tumors, and for borderline serous tumors (1.46, 1.24-1.72). Among genital powder users, we observed no significant trend (p=0.17) in risk with increasing number of lifetime applications (assessed in quartiles). We noted no increase in risk among women who only reported non-genital powder use. In summary, genital powder use is a modifiable exposure associated with small-to-moderate increases in risk of most histologic subtypes of epithelial ovarian cancer.
WHOhttp://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/talcum-powder-and-cancerInternational Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer.
• IARC classifies talc that contains asbestos as “carcinogenic to humans.”
• Based on the lack of data from human studies and on limited data in lab animal studies, IARC classifies inhaled talc not containing asbestos as “not classifiable as to carcinogenicity in humans.”
• Based on limited evidence from human studies of a link to ovarian cancer, IARC classifies the perineal (genital) use of talc-based body powder as “possibly carcinogenic to humans.”