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For
too long now breast cancer research has been dominated
by the elusive search for the cure," says Andrea Martin,
founder and executive director of the Breast Cancer
Fund, a San Francisco-based group that has launched
a major campaign to draw attention to the links between
the environment and breast cancer. Citing the fact that
only 5 to 10 percent of breast cancer cases are genetically
caused and that the number of women with breast cancer
nearly doubled between 1970 and 1990, the fund has teamed
up with the Susan G. Komen Breast Cancer Foundation
to urge the public to agitate for more research into
environmental causes of the disease. Last October the
two groups rallied 70 individuals and organizations
(including local breast cancer groups, the Coalition
of Labor Union Women, and the YWCA) to sign a letter
to President Clinton. The letter called for increased
funding for research examining environmental links;
monitoring by the Centers for Disease Control (CDC)
of what chemicals are in our bodies and in what amounts;
full funding for the Environmental Protection Agency's
(EPA) program to screen for environmental toxins; and
a cross-agency committee to oversee government funding
for environmental health research.
The
following is excerpted from the Breast Cancer Fund's
publication Examining the Environmental Links to Breast
Cancer.
Since 1971, the year President Richard Nixon
declared a "war on cancer," more than $35 billion has
been committed to research. Yet we still cannot pinpoint
with certainty the causes behind the vast majority of
breast cancer cases, nor have treatment options changed
or improved much over the years. Women still must choose
from surgery, radiation, and/or chemotherapy. In addition,
some in the medical establishment have misleadingly
focused on mammography as a prevention measure, with
the assumption that early detection can prevent serious
illness. Mammography, however, is not prevention. It
can only detect cancer that already exists and may have
been present for eight to ten years. It fails to detect
breast cancer 20 percent of the time in women over 50,
and as much as 40 percent of the time in younger women.
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Hundreds
of scientific studies of laboratory animals and wildlife
have drawn links between exposure to toxic chemicals
and cancer. Emerging science suggests that synthetic
chemicals in the environment pose a risk to the human
reproductive system, the endocrine system, and to human
growth and development both in utero and after birth.
A
rapidly evolving field of research involves the study
of "endocrine disrupters" or "hormone mimickers"--synthetic
chemicals found in pesticides like DDT, some fuels,
plastics, detergents, and pharmaceutical drugs. We know
that estrogen binds with receptors in mammary glands,
signaling cells to grow. In 1993, scientists at Cornell
University cautioned that growing evidence seemed to
indicate that exposure to estrogen-mimicking chemicals,
called xenoestrogens, can cause cells to rapidly grow
out of control and form tumors. It has been postulated
that xenoestrogens may be responsible for increasing
a woman's chances of getting breast cancer. Researchers
at Tufts University Medical School have demonstrated
that xenoestrogens make human breast cancer cells grow
in the laboratory, just as natural estrogen does.
There
are also studies that show drastic changes in development,
particularly in the reproductive system, when laboratory
mice are exposed to estrogen mimickers during critical
windows of vulnerability in utero. When cells are rapidly
developing and proliferating, there can be a key period
of vulnerability during which damaging or altering cell
development can lead to cancer. Other windows of vulnerability
include puberty and a woman's first pregnancy.
Studies
tracking patterns of breast cancer development in humans
also strongly suggest the influence of environmental
factors. In Asia, women are four to seven times less
likely to develop breast cancer than women in the U.S.
Yet when Asian women migrate to the U.S., their risk
of breast cancer rises over a two-generation span. Women
who live in the U.S. for a decade or more have an 80
percent higher risk of developing breast cancer than
more recent immigrants, and those whose grandparents
were born in the U.S. have a 60 percent greater risk
than women whose grandparents were born overseas.
Estrogen
mimickers may be either beneficial or detrimental. Estrogen-mimicking
compounds found in foods such as broccoli, soy products,
and cauliflower may act as "good" estrogens, providing
some protection against the effects of estradiol, the
chief "bad" estrogen, made naturally by our bodies.
Critics of the "xenoestrogen theory" argue that these
beneficial compounds found in foods can balance possible
hazards posed by human-made chemicals. Other scientists
point out that the human body has been fine-tuned to
handle plant estrogens through thousands of years of
evolution, while human-made estrogen mimickers have
been in the environment only since the 1940s. Since
we do not yet understand how women's natural estrogen
affects breast cancer, it is difficult to predict how
estrogen mimickers might behave, even at low doses.
Studies
have identified the presence of more than 200 foreign
chemicals in women's breast milk, including significant
levels of dioxin, a carcinogen that has been shown to
disrupt children's hormone systems. Within six months
of being breast-fed, a baby in the U.S. or Europe receives
the maximum recommended lifetime dose of dioxin. CONTINUED>>
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