Opinion: News stories miss important points of breast cancer report.

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By Julia Brody
Silent Spring Institute
Dec. 13, 2011

Maybe a ho-hum is in order about some of the reminders from the Institute of Medicine’s environment and breast cancer report released last week: Exercise is good, while exposure to unnecessary medical radiation, being overweight, consuming alcohol and using estrogen-progestin hormone treatments for menopause can increase risk.

But most of the news media missed the significance of the assessment on environmental chemicals. The real news is that the report is an authoritative statement that a cascade of scientific evidence plausibly links consumer product chemicals and pollutants with biological activity suggesting breast cancer risk.

Instead of saying what is in the report, glass-empty stories said that the IOM “failed” to “definitely” link any chemicals to breast cancer or find “clear” environmental links. Some incorrectly said the report tells women to stop worrying about consumer product risks. These stories ignore the report’s important explanation that definitive evidence is not attainable and lack of human evidence of harm doesn’t mean something is safe.

Breast cancer develops over many years, with influences beginning even before birth, and we are all exposed to myriad suspect chemicals, so clear human evidence of links to particular chemicals or mixtures is likely to remain elusive. That’s why the IOM committee also looks to experimental evidence, including animal studies, to evaluate chemicals that damage DNA or affect hormones. Their recommendation for better chemicals safety testing based on breast cancer biology is a major departure from prevailing medical skepticism and past messages that tagged concerns about chemicals as myths.

Glass-empty stories ignore the Institute of Medicine report’s important explanation that definitive evidence is not attainable and lack of human evidence of harm doesn’t mean something is safe.The IOM is partly to blame for the confusion. The slim “Questions and Answers” says, “we don’t know enough” about environmental chemicals. Sure, we need to know more, but the report gives a very different impression with its recommendation to “limit or eliminate workplace, consumer, and environmental exposures to chemicals that are plausible contributors to breast cancer risk while considering risks of substitutes.” That recommendation was ignored by most media.

The report calls out three chemicals in particular – ethylene oxide, benzene, and 1,3-butadiene – as “probably human breast carcinogens.” As far as we know, this is the first statement by an authoritative medical group linking any specific environmental chemical to breast cancer. The primary exposures to benzene and 1,3-butadiene are from vehicle exhaust. Ethylene oxide is a sterilant used, for example, in medical settings and food sanitation. My own list of chemicals with both human and animal evidence would be longer, including polychlorinated biphenyls (PCBs), found in certain fish and in air in older buildings; polycyclic aromatic hydrocarbons (PAHs), from combustion-related air pollution, tobacco smoke, and grilled food; and organic solvents, used in glues and cleaners.

The IOM highlights chemicals with hormonal activity, including perfluorinated compounds, bisphenol A and the pesticide atrazine, as priorities for research because the evidence of plausible biological links to breast cancer is “provocative” but difficult to interpret so far. The committee calls for better consumer information about product ingredients, so shoppers can make choices while science and regulatory assessments unfold.

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With the rich analysis in the 364-page IOM report, it’s disappointing to see reporters quoting experts who seem to think women can’t walk and chew gum – that they can’t, for example, control their weight and avoid solvents at the same time – so we shouldn’t distract ourselves with multiple messages about breast cancer risks. For the many women who have already taken the IOM’s recommended healthy lifestyle steps, the report offers science support for additional action:

• If you walk, run, kayak, or shop to stop breast cancer, tell your event sponsors to spend your dollars to implement the recommendations in this report.

• To reduce exposures to benzene and 1,3-butadiene, try to avoid breathing car exhaust and choose vehicles with better gas mileage or electric power.

• To avoid organic solvents in paints, strippers, glues and dry cleaning, minimize use and be sure to ventilate. Use a solid carbon filter for drinking water if your community has detected solvents in the water supply.

• The IOM report says Americans need to know more about gaps in consumer product safety testing, but it stops short of recommendations to fix the problem. To get educated and advocate for change, I think the Safe Chemicals Healthy Families coalition is a good place to start. Meanwhile, if you are choosing products to reduce your own exposure, the take-action tips from Silent Spring Institute offer simple steps.

Breast cancer is still a killer, the leading cause of death for women in midlife, and an enormous source of suffering for the 230,000 U.S. women diagnosed each year. Perhaps the media’s frustration with lack of “answers” in the IOM report reflects how desperately we all want to know how to prevent this disease. Because breast cancer is so common and the suspect chemicals so widespread, the nationwide benefit of finding and eliminating the risks would be large, even if the incremental risk to any one woman is small.


Julia Brody, Ph.D., was a reviewer of the IOM report. She is the lead author of the 2007 Cancer supplement “Environmental Factors and Breast Cancer” and the Executive Director of Silent Spring Institute, a scientific research nonprofit institute. She is an adjunct assistant professor at Brown University Medical School.



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