MONDAY, Jan. 12, 2004 (HealthDayNews) -- The most common group of chemicals used as preservatives in cosmetics and deodorants has been detected for the first time in human breast cancer tissue.
Although the discovery by a British oncology expert points to a link between breast tumors and the chemical group called parabens, it is not clear exactly what the relationship is and many important questions still need to be answered.
The U.S. Food and Drug Administration has called parabens the most widely used preservatives in the United States, common in shampoos, foundations, facial masks, hair-grooming aids, nail creams, and permanent wave products. Different animal and laboratory studies have previously shown that parabens can mimic the actions of the hormone estrogen. That has raised red flags because estrogen is known to fuel breast cancer.
The latest, apparently groundbreaking research takes those findings one step further.
"We have always been assured that parabens could not get into the body . . . This study shows that it does. To my knowledge, no one else has done that," says Philippa D. Darbre, the lead author of the study, which appears in the January/February issue of the Journal of Applied Toxicology.
"It's one more nail in the coffin, or one more piece in the jigsaw," Darbre adds.
"It's preliminary, but I think that it's a little worrisome and I think there's definitely enough data here to suggest that more work needs to be done to look at this issue," adds Dr. Bert Petersen, a breast surgeon and director of the Family Risk Program at Beth Israel Medical Center in New York City. "I don't think it can be dismissed."
A 1984 study estimated parabens were used in 13,200 different cosmetic formulations. Of particular concern are underarm products, such as deodorants and antiperspirants, which are applied topically and absorbed through the skin.
Darbre, a senior lecturer in oncology at the University of Reading in England, has been studying breast cancer for 20 years and has long been interested in parabens but could not get funding for this study.
"I was told I wouldn't find anything," she says. So, she galvanized friends and colleagues in the medical community who helped her gain access to analytic machinery and to breast tissue.
Eventually, Darbre was able to analyze samples of 20 human breast tumors with high-pressure liquid chromatography followed by tandem mass spectrometry.
In four of the 20 tumors, total paraben concentration was more than twice the average level. The form the chemicals were found in suggests they entered the body topically, not orally, the researchers add.
"We've detected an awful lot of other rubbish in the human body," Darbre says. "This is another one to add to the dustbin."
The Cosmetic, Toiletry and Fragrance Association defends the safety of parabens: "A wealth of data supports the safety of antiperspirants," a statement reads. "The Food and Drug Administration (FDA) regulates cosmetics and nonprescription drugs to assure their safety. There is no evidence of harm from the use of deodorants or antiperspirants. They are safe, and consumers should not be unnecessarily alarmed."
The study authors acknowledge many issues need to be resolved before any definitive conclusions can be reached. "A lot of questions are begging from this," Darbre says. "Lots of things need to be done. I've set the scene."
Researchers need to determine levels of parabens in normal breast tissue and in other parts of the body. Also, more samples should be examined.
"It would be interesting to see if normal women had very low levels of parabens," Petersen says. "Then you would start to move towards maybe this isn't just an association. There might be a causal effect here."
Darbre hopes her study will spur further investigation.
"My hope is that someone else will take this up, or that someone might decide it's worth funding," she says.