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Is there any proof linking human breast cancer to
exposure to chemicals in the environment, or do researchers think most
cases of breast cancer are genetically inherited?
A groundbreaking research study coordinated by the
nonprofit Silent Spring Institute and recently published by the American
Cancer Society found that synthetic chemicals have likely played a large
role in the rising incidence of breast cancer throughout the world over the
last half-century. The study identified 216 manmade chemicals —
including those found in everyday products such as pesticides, cosmetics,
dyes, drugs, and gasoline (and diesel exhaust) — that have been shown
to cause breast cancer in animals. Researchers believe these substances,
many of which mimic naturally occurring hormones once inside the body, are
also to blame for the increasing prevalence of human breast cancer. According to epidemiologist Devra Lee Davis of the
University of Pittsburgh’s Graduate School of Public Health and one
of the lead researchers on the new study, the more hormones cycling through
a woman’s body during her lifetime, the more likely it is that breast
cancer will develop. Synthetic chemicals that mimic hormones magnify the
risk because the body doesn’t know the difference between its own
real hormones and other introduced chemicals. Only one in 10 women in whom
breast cancer develops inherits a defective gene from her parents, Davis
adds, meaning that in 90 percent of breast-cancer cases studied, external
nongenetic agents such as synthetic chemicals contributed to the
development of the cancer. Another telling clue is the fact that the
breast-cancer risk of adopted children parallels the risk of the families
they grew up in, not that of their biological families, as proved by
analysis of medical records from Scandinavian countries that keep detailed
registries following people from birth to death. “What we understand is that if cancer runs in
your family it could be because your family had similar eating patterns
[and] similar lifestyle patterns as well as lived in the same area,”
Davis says. “It’s really important that we take another look at
. . . the kinds of chemicals that we are using every day,” she adds.
“We think that there are alternatives that can be used.”
The U.S. government has been reluctant to institute
new restrictions on the production of highly profitable synthetic
chemicals, but European regulators are taking the issue very seriously. The
European Commission’s new Registration, Evaluation, Authorisation and
Restriction of Chemicals program calls on chemical manufacturers selling
anywhere in Europe to reregister and reevaluate the potential health
hazards — including cancer risks — of their products.
Environmental and public-health advocates hope that American chemical
companies will follow that lead with chemicals sold here. In the meantime, consumers can help prevent cancer by
buying and eating organic foods, avoiding pesticides and other synthetic
chemicals whenever possible, using nonplastic containers to reheat and
store foods (some plastics are thoughts to leach cancer-causing chemicals
into food when heated), and supporting government regulation and more
research on synthetic chemicals and their effects.
For more information:
Silent Spring Institute, www.silentspring.org; European Commission’s
REACH Program, ec.europa.eu/environment/chemicals/reach/reach_intro.htm.
Send questions to Earth Talk, care of E/The Environmental Magazine,
P.O. Box 5098, Westport, CT 06881 or e-mail earthtalk@emagazine.com.
This article appears in Jun 21-27, 2007.
