SAN ANTONIO, Dec. 17 -- Breast cancer patients may unknowingly expose themselves to estrogen by using certain skin moisturizers, a breast cancer survivor reported here.
Laboratory analyses identified a half-dozen different products containing measurable levels of estriol and estrone, Adrienne C. Olson, Pharm.D., of Breastlink in Rancho Palos Verdes, Calif., told attendees at the San Antonio Breast Cancer Symposium.
None of the products listed the estrogenic hormones among its ingredients.
"No one could tell from reading the ingredients that the products contained estrogenic hormones," she said.
- Explain to patients that this study showed that some skin moisturizers contain estrogens.
- Point out that breast cancer patients' risk from exposure to estrogen-containing skin creams is unclear.
- Note that this study was published as an abstract and presented orally at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
Dr. Olson became interested in the estrogen-moisturizer association during her own treatment for estrogen receptor-positive breast cancer. Chemotherapy-induced menopause caused her skin to become dry and wrinkled.
So she began using a moisturizer that restored her skin's natural appearance.
In fact, the moisturizer worked so well that she suspected the product might contain estrogen, which helps maintain skin integrity and promote a "youthful appearance."
Following up on her suspicions, Dr. Olson collected containers of 16 nonprescription skin moisturizers, spanning a wide cost range.
She sent the samples to a research laboratory, which tested the products for the presence of estradiol, estrone, and estriol.
Analysis by high-performance liquid chromatography (NPLC) revealed estrone at a concentration of 0.05% in one of the products and estriol in five others at concentrations ranging from 0.17% to 0.61%.
Some of the other products might contain lower levels of the hormones that were not detected by HPLC, she added. Moreover, the product analysis did not include testing for customized or designer estrogens.
Whether this transdermal exposure to estrogenic hormones can influence the behavior of ER-positive breast tumors is unclear.
"Until the late 1970s, the intact epidermis was thought to be impermeable to medications in creams and ointments," said Dr. Olson. "We now know that the skin is much more porous than we previously believed."
Enforcement of FDA regulations pertaining to cosmetics is based on the outdated concept of the skin as an impermeable barrier, she added.
"We're just concerned," said Dr. Olson. "We want women to be informed. I personally use baby oil on my skin and nothing else."