What Causes Breast Cancer?

     They say the first thing a woman does when she’s diagnosed with breast cancer is to question how she might have gotten it. Which of life’s choices could’ve led to it: garden pesticides, household cleaners, birth control pills, children/no children, hormone replacement therapy/or no HRT, alcohol, smoking or second-hand smoke, our drinking water?

     Some years ago a survey was done in Marin County as the county’s incidence of breast cancer is so high. I had to laugh at some of the theories that surfaced afterward. One of them postulated that the women of Marin drink more alcohol and are more apt to subscribe to HRT, both of which can lead to breast cancer. Well, a liver dysfunction has prevented me from drinking alcohol these past twenty years, and I never had hormone treatments. I’m glad to see scientists are broadening their research.

     The November after my diagnosis, I attended a community forum sponsored by Zero Breast Cancer of San Rafael. Keynote speaker Dr. Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, spoke of the environmental triggers of breast cancer. She noted that it is a “major killer of U.S. women, and it’s an equal opportunity killer.” Contributors to breast cancer, she said, are obesity, stress, environmental toxins, and exposure to such chemicals as:

• BPA: Bisphenol A is the building block of polycarbonate plastic and is used in food packaging. Research suggests BPA exposure may contribute to the epidemic of breast cancer now and in the future.
• Dioxins: These environmental pollutants are of concern because of their highly toxic potential. Experiments have shown they affect a number of organs and systems.
• PCBs: The manufacture of PolyChlorinated Biphenyls was halted in the U.S. in 1977 because of evidence they build up in the environment and can be harmful to human health.

     Other factors being studied as possible contributors to breast cancer, according to the forum’s panelists, include:

• Chemicals used in beauty salons.
• Exposure to diesel fumes.
• Endocrine disruptors, which influence estrogen production. These disruptors can be found in plastics and in cosmetics.
• Synthetic estrogens.
• Flame retardants, which are used in everything from furniture to computers.
• Certain pesticides.
• Exposure to truck exhaust.

     Interestingly, it takes 20 to 30 for breast cancer to develop in women. This is why one study is now following girls in puberty. Researchers want to know what “environmental factors contribute to early puberty and which exposures that occur in puberty may increase breast cancer later in life.”