Breast cancer risks all around us

Marla Cone, "Breast cancer risks all around us", Sydney Morning
Herald, Australia, May 15, 2007,
Link: http://www.smh.com.au/news/national/...995079791.html

MORE than 200 chemicals - many found in urban air and everyday
products - cause breast cancer in animal tests, according to a
compilation of scientific reports.

Reducing exposure to the compounds could prevent many women from
developing the disease, say researchers writing in a publication of
the American Cancer Society.

Experts say family history and genes are responsible for a small
percentage of breast cancer cases, but the vast majority involve
environmental or lifestyle factors such as diet.

It is expected that more than 2500 Australian women will die of the
disease this year, and that more than 13,000 new cases will be
diagnosed.

The researchers named 216 chemicals that induce breast tumours in
animals. Of those, people are highly exposed to 97, including
industrial solvents, pesticides, dyes, petrol and diesel exhaust
compounds, cosmetics ingredients, hormones, pharmaceuticals, radiation
and a chemical in chlorinated drinking water.

Seventy-three of the products are in consumer products, such as 1,4-
dioxane in shampoos, or are food contaminants, such as acrylamide in
chips, crisps and biscuits.

Thirty-five of the products are common air pollutants, and 10 are food
additives.

In the journal Cancer, the researchers said the data was too
incomplete to estimate how many breast cancer cases might be linked to
chemical exposures.

But because the disease is so common and the chemicals so widespread,
"the public health impacts of reducing exposures would be profound
even if the true relative risks are modest," they wrote. "If even a
small percentage is due to preventable environmental factors,
modifying these factors would spare thousands of women."

Research in the past five years has "strengthened the human evidence
that environmental pollutants play a role in breast cancer risk," the
researchers wrote.

The three reports and a commentary were compiled by researchers from
the Silent Spring Institute, Harvard University's Medical School and
School of Public Health in Boston, the Roswell Park Cancer Institute
in Buffalo, New York, and the Keck School of Medicine at the
University of Southern California.

"Almost all of the chemicals were mutagenic, and most caused tumours
in multiple organs and species; these characteristics are generally
thought to indicate likely carcinogenicity in humans, even at lower
exposure levels," they reported.

No new chemical testing was conducted for the reports.

The chief executive of The Cancer Council Australia, Ian Olver, said
it was known that some of these things could cause cancer. He said:
"We know that we're exposed to a whole mixture of these cancer-causing
chemicals in our everyday life ...

"We know these things can cause cancer in some systems in animals, but
we haven't got enough information to say if we managed to reduce our
exposure to these that breast cancer would drop by a specific amount.
We just don't know that."

The chief cancer officer at the NSW Cancer Institute, Professor Jim
Bishop, said the research was an "interesting lead" into how we might
fight cancer in the future, but he cautioned against reading too much
into the findings.

"Animal breast cancer doesn't always behave the same as human breast
cancer," he said.