December 7th, 2011
06:04 PM ET
A report, released by the Institute of Medicine on Wednesday, says there are steps women can take to reduce their risk of getting breast cancer that is associated with environmental exposures.
The IOM says there are several environmental factors that can increase a woman's chance of getting breast cancer. According to the report, "Breast Cancer and the Environment," exposure to ionizing radiation (that's radiation associated with diagnostic tests such as mammograms, X-rays and CT-scans) is one such environmental factor.
Others include combination estrogen-progestin hormone therapy, oral contraceptives and weight gain - especially after menopause. Limiting alcohol consumption and not smoking, staying physically active and avoiding weight gain also help reduce the risk, the study found. When researchers talk about environmental factors, they are referring to anything that is not related to inherited DNA.
It is less clear how exposures in the workplace to things like gas fumes and car exhaust, or chemicals found in things like benzene (a solvent used to make lubricants, dyes, detergents and pesticides) or ethylene oxide, a chemical used in antifreeze, adhesives and even cosmetics add to the risk of getting breast cancer. The committee found that because there is such little testing on chemicals in cosmetics, dietary supplements and other products before they actually go to market, they were unable to draw conclusions as to whether minimizing exposure to these chemicals is actually beneficial.
The committee stressed more research is needed on environmental exposures over the course of a lifetime, with special attention paid to various stages of breast development, as well as cumulative and multiple exposures at different life stages, including in the womb.
"Breast cancer develops over many years, so we need better ways to study exposures throughout women's lives, including when they are very young," said committee chair Irva Hertz-Picciotto, a professor in the department of public health sciences at the University of California, Davis, School of Medicine. "We also need improved methods to test for agents that may be contributing to breast cancer risk and to explore the effects of combined exposures."
The IOM says the jury is still out on whether chemicals like bisphenol A (BPA), a chemical used in plastics to make them more flexible, contribute to a woman's risk of getting this type of cancer, but multiple studies found no link between breast cancer and hair dyes, or radiation emitted by cell phones and other electronic devices.
"This is an important report that carefully reviews the evidence of how women can reduce their risk of breast cancer," says Dr. Michael Thun, vice president emeritus in epidemiology for the American Cancer Society. "There is accumulating evidence that active smoking in childhood and adolescence also increases breast cancer risk."
According to the American Cancer Society about 230,500 women in the United States have been diagnosed with invasive breast cancer this year. Nearly 40,000 women are expected to die this from this cancer this year. Only lung cancer causes more cancer deaths in women.
Susan G. Komen for the Cure commissioned the study. KomenPresident, Elizabeth Thompson, said the foundation, which has invested nearly $2 billion in finding a cure for breast cancer, will start a fund to work on initiatives addressing breast cancer and environmental links.
"Understanding the role that environmental factors play in the development of breast cancer is hugely complex and IOM has done a good job laying out the challenges," Thompson said. "We intend to use these findings to guide our decisions about research to fund so that women and their families have the best science to guide them in making important lifestyle choices. We believe our efforts going forward will be made even more effective through the guidance provided by this study."
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