23 October 2002
Cancer Puzzle in Marin
California County's Rate of Disease Is Almost 40% Higher Than U.S.
Special to The Washington Post
RAFAEL, Calif. -- Marin County, long-famed as a mecca for wealthy
hot-tubbers, has recently acquired a darker distinction. Women in
these scenic valleys north of San Francisco are being diagnosed
with invasive breast cancer at a higher rate than experts have found
anywhere else in the United States.
the past five years, non-Hispanic white women, the hardest-hit group
in this county, have received a diagnosis of breast cancer at a
rate nearly 40 percent higher than the national norm. Just as striking
is how the rate steadily climbed through the 1990s, increasing 37
percent, compared with 3 percent for the rest of the San Francisco
predicament has acquired special import in an era when breast cancer
rates throughout the developed world have been rising, when more
than 40,000 U.S. women are dying of the disease every year, and
when scientists increasingly are raising questions about the possible
influence of exposure to industrial chemicals. But even as local
activists search for environmental smoking guns -- such as links
to toxic waste dumps or cellular telephone towers -- experts say
women here are most likely vulnerable because of something in this
county's lifestyle, rather than in its water.
don't think there's strong evidence of unique exposure to an environmental
harm," says Christina A. Clarke, an epidemiologist at the Northern
California Cancer Center and a leading expert on Marin's plight.
and other researchers say Marin's status may be largely explained
by its attributes as one of the nation's smallest urban counties.
Its 250,000 residents are predominantly white and well-off financially,
characteristics long associated with higher rates of breast cancer.
Cancer rates are reported for counties, but not for cities and towns.
If they were, Clarke says, places such as Beverly Hills, Calif.,
or Chevy Chase might exhibit similarly high breast cancer rates.
status could potentially help women elsewhere if activists succeed
in encouraging further local research, making the county, as Clarke
hopes, "a petri dish" to study what it is about the life
of a professional, well-off white woman that makes her so susceptible
to breast cancer.
has been steadily accumulating to reinforce this connection. Results
published last month of an ongoing study of 133,479 California teachers
and administrators found a rate of invasive breast cancer that was
51 percent higher than that found in non-Hispanic white women of
a similar age throughout the state.
offer several possible explanations. Educated, professional women,
such as the teachers and a great portion of Marin's female residents,
generally have better access to medical care, including screening
for cancer; that leads to more diagnoses. Better medical care may
also have included more combined hormone replacement therapy, only
recently linked to increased breast cancer risk. Furthermore, in
a family with two professional incomes -- especially common in Marin,
where the average household income tops $80,000, almost $30,000
more than national average -- women often delay having children
or do not have them at all. These characteristics have long been
thought to increase the risk of breast cancer, the theory being
that such women have more menstrual cycles at a younger age, exposing
them to higher levels of estrogen, which can encourage tumor growth.
these issues, women here worry about a host of other possible dangers
hidden in what looks like a fortunate lifestyle: the hectic schedule
of two working spouses, pesticides on lawns, the chemicals in the
plastic bottles of the ubiquitous designer water.
always thought it was the stress," says Christine Schadlich,
42, a former real estate portfolio manager diagnosed with breast
cancer three years ago, just after the birth of her second child.
"It takes a lot of effort to maintain things here, with two
parents working. My health was always on the margin."
have long known that chronic stress can harm people's immune systems.
In recent years, several studies have indicated that a common way
to cope -- by having a few drinks, as Schadlich says she often did
-- is associated with higher rates of breast cancer, though the
medical reasons for this remain unclear.
says she quit drinking after her diagnosis. She also quit her job
and says she is trying to simplify her life. Even so, she felt frustrated
when her doctor, as she tells it, attributed her case to demographics.
word raises the hackles of many women concerned about cancer, particularly
those who feel it dismisses concerns about circumstantial evidence
linking widely used chemicals, including some found in plastics
and pesticides, to rising rates of breast cancer.
easy for them to say 'demographics', but -- hello? There hasn't
been enough research yet into what's in our air and in our soil
and in the products we use," says Fern Orenstein, 44, a six-year
cancer survivor and health education specialist. "Maybe what
it is isn't unique to Marin, but maybe it is environmental, and
we just have more of it here."
many residents share these suspicions that on Nov. 9, 3,000 community
volunteers for the Marin Cancer Project are planning to go door
to door polling residents and asking for a $1 donation to map the
incidence of all types of cancer. "The response has been like
in the movie, 'Field of Dreams,' " says the group's director,
Judi Shils. "If you build it, they will come."
tracking potential environmental factors in breast cancer is extraordinarily
difficult, experts say. The interaction between an individual's
genes and exposure to potential toxins is complex, and is why some
smokers get lung cancer, while other smokers do not.
August, scientists involved in a study of reportedly high breast
cancer rates in Long Island said they had found no links to pollution
or other environmental factors. The research, supported by $30 million
in federal funding, had focused on industrial chemicals, including
two recognized "endocrine disruptors" -- substances that
can affect hormonal systems. But the lack of conclusions hasn't
know that lifetime exposure to estrogen is a risk factor,"
says Sheldon Krimsky, a Tufts University professor who studies environmental
health hazards. "So it is logical that if we have chemicals
that are creating more estrogen, the risk may go up." Such
chemicals, says Krimsky, can be found in cosmetics, lawn care products,
household cleansers and certain plastics, but research into their
potentially harmful effects is moving "at a snail's pace."
Marin Breast Cancer Watch, a group of survivors and other activists,
has been fighting to focus attention on environmental exposure since
1997, when women began sticking pins on a map to see if the cancers
members have supported five different small studies, funded by county,
state and federal agencies, including a three-year project comparing
the adolescent experiences of 300 Marin County breast cancer patients
with those of 300 local women who do not have the disease.
finding that may be illuminating is how long women say they have
lived in the county. Clarke hypothesizes that the climb in the local
breast cancer rate in the 1990s owes to departure of low-income
women who could no longer afford to live there. The group took pride
in a recent visit from Kenneth Olden, director of the National Institute
of Environmental Health Sciences at the National Institutes of Health.
"You've made your case that rates are higher here than anywhere
else," he told them, "and you deserve our attention."
an interview, however, Olden said he hadn't heard convincing evidence
linking the high cancer rates to any particular environmental problem.
"It looks like it's going to be demographics," he said.
the search goes on for exactly what that means -- what special risks
women here face -- Marin may have much to teach the country.
are lots of educated, affluent women scattered around the country,"
Clarke says. "For them, Marin women may be canaries in the
2002 The Washington Post Company