Kristi Nelson, NBC 5 News
Women should avoid exposure to medical radiation, not take menopause hormones, not smoke, limit alcohol consumption, exercise and avoid weight gain, according to a study presented in San Antonio.
Women concerned about breast cancer should worry less about cellphones and hair dyes and worry more about weighing or drinking too much, exercising too little, using menopause hormones and getting too much radiation from medical tests. So says a new report on environmental risks by a respected panel of science advisers.
By environment, they mean everything not governed by genes -- what's in the air and water but also diets, vitamin use and even things such as working night shifts.
And while they lament that most chemicals in consumer goods get little safety testing, they find too few studies in people to say whether there is a breast cancer risk from certain pesticides, cosmetics or bisphenol A, known as BPA and used in many plastics and canned food liners, although it has been eliminated from baby bottles and many reusable beverage containers in recent years.
"We don't have enough data to say 'toss your water bottles,"' said Irva Hertz-Picciotto, chief of environmental and occupational health at the University of California, Davis.
She headed the Institute of Medicine panel -- independent experts under the National Academy of Sciences who advise the government and others. This report was paid for by Dallas-based Susan G. Komen for the Cure, a breast cancer foundation. It was presented Wednesday at a cancer conference in San Antonio.
We've done a better job of treating breast cancer than preventing it, said Dr. Michael Thun, senior epidemiologist for the American Cancer Society, who helped review the report. Breast cancer death rates in the U.S. fell 31 percent from 1990 to 2007, but incidence rates declined only about 5 percent.
Weight and obesity matter because fat cells make estrogen, and that hormone fuels the growth of most breast cancers, he said.
Other factors are more complex. Moderate alcohol consumption may lower the risk of heart disease but seems to raise the risk of breast cancer a little.
The report sorts the evidence for higher breast cancer risk factors like this:
"There's a tremendous desire to blame someone or something" for breast cancer, said Dr. Eric Winer, a cancer specialist at Dana-Farber Cancer Institute in Boston and chief scientific adviser to the Komen foundation.
"There's a real danger in prematurely concluding that a substance is the culprit and then closing your eyes and not paying attention to what might be a much more concerning factor," or substituting something for BPA that might be worse, he said.
Thun of the cancer society agreed.
"One should first do everything possible to address the known risk factors," he said. "If I'm making the choices, I wouldn't put this (BPA) at the top of my list."
However, Laura Anderko, a Georgetown University Medical Center public health scientist, said she was "deeply disappointed" by the report's heavy emphasis on personal responsibility for cancer prevention.
"It is in stark contrast to the President's Cancer Panel report last year that has a strong call to action on chemical policy reform," she wrote in an email.
About 230,000 cases of breast cancer are expected to be diagnosed this year in the United States. Less than 10 percent of cases are due to inherited genes.