Oakland (Calif.) Tribune
January 24, 2006

STUDY: HALF BREAST CANCERS TIED TO ENVIRONMENT

Rachel's summary: A review of 350 studies of breast cancer concludes
that exposure to chemicals and radiation may be contributing to half of
all new cases, or 106,000 breast cancers each year.

Analysis of 350 studies finds half of cases are unrelated to genetic
risk or lifestyle choices

By Douglas Fischer

As many as half of all new breast cancers may be foisted upon women by
pollutants in the environment, triggered by such items as bisphenol-A
lining tin cans or radiation from early mammograms, according to a
review of recent science by two breast cancer groups.

Their report, "State of the Evidence," released Tuesday [Jan. 24],
buttresses what many researchers increasingly suspect: that repeated
low doses -- particularly in early childhood -- to chemicals normally
considered harmless can have a profound effect.

It also suggests that, for half of the 211,240 woman diagnosed with
breast cancer in 2005, lifestyle choices and genetics played no role.

"You just can't blame it on lifestyle factors, like when you have
children, or if you have children," said Nancy Evans, health science
consultant for the Breast Cancer Fund and the report's principle
author.

"Half the cases are not explained by genetics or the so-called 'known
risk factors." There's something else going on."

The report, by the San Francisco-based groups Breast Cancer Fund and
Breast Cancer Action, analyzed the findings of more than 350
experimental, epidemiologic and ecological studies assessing breast
cancer.

Breast cancer rates have climbed steadily in the United States and
other industrialized countries since the 1940s. In the U.S., for
instance, one in seven women will be diagnosed with breast cancer in
her lifetime, almost triple the rate in the 1960s.

Researchers believe less than one in 10 cases occur in women born with
a genetic predisposition for the disease. Instead, the report says,
recent science makes very clear the cancer arises from a multitude of
factors, from slight genetic mutations to altered hormone production
to even radiation.

For instance, the report cited a study from Tufts University that
found that exposing pregnant mice to extremely low levels of
bisphenol-A altered the development of the mammary gland in their
offspring at puberty.

And that alteration makes the gland more susceptible to breast cancer,
Evans said.

Bisphenol-A, originally developed as a synthetic hormone in the 1930s,
today is used as an additive to make plastic shatterproof and to
extend the shelf-life of canned goods. Nearly 6 billion pounds are
produced annually.

Industry has long maintained there is no evidence repeated low doses
of compounds such as bisphenol-A can have such deleterious effects. A
legislative effort to ban some of these chemicals from children's toys
failed last week after industry scientists argued there was no cause
for concern.

"A lot of work has been done on those issues," said Lorenz Romberg, a
former U.S. Environmental Protection Agency scientist who now works as
a consultant and testified before the Legislature on behalf of the
chemical industry last month. "When you look at this body of evidence
in total, we didn't find any evidence that there is a marked,
repeatable-across-laboratories effect that has any clear scientific
standing."

But the report, Evans said, makes clear there is no one culprit for
rising breast cancer rates. What happens, for instance, when
bisphenol-A or any several estrogen-like synthetic compounds on the
market gets combined with the harm from a few low-dose X-rays?

No one knows, but new research from the National Academy of Sciences
suggests there is no safe radiation dose: The lowest possible dose
still increases cancer risk. Yet the American Cancer Society still
recommends women over age 40 have a mammogram, despite evidence such
procedures are not effective until women are 50 years old.

"We have to have a replacement for mammography. It's so aggressively
promoted, especially for young women," Evans said.

But does the chance of early detection outweigh the risks?

"I'm not saying they should or shouldn't," Evans said. "They need to
be aware of the risk. An additional 10 years of radiation is not
insignificant."

The report, "State of the Evidence," can be found here. Contact
Douglas Fischer at dfischer@angnewspapers.com.

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