Methylparaben Accumulation Noted In UK Breast Tumor Study

Additional research, including studies measuring the levels of parabens in healthy breast tissue, is needed to evaluate the possible connection between the cosmetics preservatives and breast cancer, according to a British study published in the January issue of the Journal of Applied Toxicology.

The preliminary study by P.D. Darbre, MD, University of Reading, et al., found high levels of parabens in 20 breast tumor samples. "It will now be important to measure levels in corresponding normal tissue to determine whether there is any difference between normal and cancer tissues," the authors point out.

"Larger studies also are needed to give more representative values for body burdens in different tissues and across the human population," Darbre et al. note. The researchers add it will also be important in future work "to have more precise histological information on the tumors in order especially to be able to relate results in fatty versus non-fatty tissue."

Such information, "taken together with that of concentrations in tissues of endogenous steroid hormones and other xenoestrogens, should enable assessment to be made of the impact of these weakly [estrogenic] parabens on human health and whether paraben accumulation from currently permitted levels in cosmetics, foods and pharmaceuticals remains acceptable."

Concern with the safety of the ingredient stems from a 1998 study, which found parabens mimic the hormone estrogen, a known factor in the growth and development of breast cancer.

Parabens are used as preservatives in antiperspirants and deodorants as well as other cosmetic products in levels of up to 1%. A 1995 survey of 215 cosmetic products found that parabens were used in 99% of leave-on products and in 77% of rinse-off cosmetics, according to the authors.

The Cosmetic, Toiletry & Fragrance Association maintains the "vast" amount of antiperspirant/deodorant formulations now on the market do not contain parabens.

In the study, tumor samples were analyzed for parabens by high-pressure liquid chromatography and tandem mass spectrometry. The process found five esters of parabens in the tissue: methyl, ethyl, n-propyl, n-butyl and isobutyl. Methylparaben was present at the highest level, representing 62% of total parabens recovered from the extraction.

The extensive presence of methylparaben in the tissue may reflect the "more widespread use of methylparaben in consumer products," the researchers noted. "Alternatively, it may reflect the greater ability of methylparaben to be absorbed into body tissues," Darbre et al. add.

The researchers note the study fails to identify whether the parabens entered the body by oral or topical route. Nor did the study determine whether they "entered the human breast by a systemic route or through non-systemic mechanisms involving simply local absorption and diffusion from chemical overload of topical preparations applied to the breast area."

In an accompanying editorial, Philip Harvey, MD, Covance Labs, UK, et al. state "the findings of parabens in tumor samples are additional results in line with the general hypothesis that there may be a link between [estrogenic] compounds commonly used in underarm cosmetics and other consumer products and breast cancer."

"The results alone, however, do not suggest that these chemicals caused the tumors in these patients," the editorial adds. "Darbre et al.'s findings invite several questions: how did the parabens get into the breast, are they persistent and could they do harm? The answers require further research."

The safety of underarm personal care products was addressed in a study published in the October 2002 Journal of the National Cancer Institute. Conducted by Dana Marick, Fred Hutchinson Cancer Research Center, Seattle, et al., the case-control study concluded antiperspirants and deodorants were not linked to an increased risk of breast cancer (¹ 'The Tan Sheet' Oct. 21, 2002, In Brief).

The Cosmetic Ingredient Review Expert Panel decided in November to consider reopening its safety assessment of parabens and may take up the issue at its June panel meeting. The group concluded in 1984 the ingredients were safe in cosmetics.

In a Jan. 14 statement defending the safety of parabens, CTFA maintains the Darbre study is "very preliminary and "based on a small sample size with inconsistent results." A "wealth of data supports the safety of antiperspirants and parabens," the association asserts.