Breast Cancer’s Cause & Controversy

Part One: Cause & Controversy
• Part Two: A Plague of Neglect
• Sidebars: Risk Factors; Toxic Links; Long Island
• Printable: Download the magazine-style PDF

By Carl Hall, special to

For Nancy Rubin, director of the Marin County Department of Health and Human Services, it’s high time for some answers.

“I am taking this really seriously because my community is taking it really seriously,” she said. “I have a responsibility to the community. Pure and simple.”

Her community — the overwhelmingly white, well-to-do population ( of Marin County — is rallying against what they perceive as a nationwide epidemic of breast cancer, one that is crashing down hardest on that idyllic stretch of forested countryside just north of the Golden Gate Bridge.

Assuming a life span of 85 years (the average is around 77), the latest statistics from the Northern California Cancer Center indicate about 12.6 percent, or one in eight, of U.S. women can expect a breast cancer at some point in their lives.

In Marin, the rate has been closer to one in six (, the highest overall rate of Bay Area breast cancer by a wide margin — 154.4 cases a year on average per 100,000 women, vs. 100.3 cases per 100,000 in San Francisco and 107.2 in the East Bay’s Alameda County.

Part of the reason Marin’s rates are so high is simple: Breast cancer is far more common among white women than minorities, and Marin has a higher proportion of white women.

In the latest tally, 130.5 annual cases of breast cancer were reported for white women in the Bay Area, compared with 97.1 cases among African Americans and 71.1 for Asians/Pacific Islanders.

But these ethnic variations do not shed much light on why Susan Dotto of San Rafael, with no family history of breast cancer, who worked for years in a “superclean” office job before taking on the full-time career of homemaker, was diagnosed with breast cancer shortly after her 35th birthday.

Now 37, she came through chemotherapy, mastectomy and reconstruction, and now is “doing great” with no hint of recurrence.

But she is still troubled by the fact that she has no idea what made her sick in the first place.

Difficult Questions, Elusive Answers

What is the source of breast cancer in Marin?

“I just don’t know,” Dotto said, offering such possibilities as the high stress Marin lifestyle, full of fast cars and pressure-cooker commutes despite a reputation for hot tub spiritualism.

“Maybe something in the water, or air, I don’t know,” she continued. “I’d love to find out. Whatever it is, why does it affect some people and not others? I have two girls now and I would love it if somebody could figure it out before they are of the age when they have to start worrying.”

Such unknowns add a frightening element to the lovely Marin landscape, where — chronic traffic congestion aside — good health and natural living seem to dominate as in few other places.

“It’s horrifying, actually,” says Francine Levien, a cancer survivor who founded and heads Marin Breast Cancer Watch, a nonprofit patient-advocacy group founded in 1995, and supported by private donations, grant projects and a community silent auction.

“Right now we know that we have a high rate of breast cancer compared to other places. We don’t have any conclusive evidence why that is,” says Levien. “This is not a Marin epidemic, we just happen to have the highest rate.”

Based on the latest evidence, cancer rates in Marin are about as depressingly high as one would expect given the demographics of the community and the prevalence of known risk factors for the disease.

But medical experts are hoping some cutting-edge research will provide more answers.

One project now underway will take a look at how adolescent risk factors may contribute to cancers diagnosed in middle age.

“A number of studies suggest that there are times in the lives of females when breast tissue is more susceptible to insult and injury,” said Dr. Georgianna Farren, a local physician and researcher affiliated with the University of California at San Francisco, and working in collaboration with Marin Breast Cancer Watch.

That’s why Farren decided to look at more than just the current lifestyles of Marin women. She is conducting in-depth interviews with 600 women, including 300 breast cancer cases and 300 controls who are free of the disease, to find out whether the women with cancer had exposures or experiences in adolescence that may help explain how the disease process got started.

Going in-depth

Her study plan illustrates the difficulty of getting clear answers. To figure out what may be giving people cancer today, Farren has to peer several decades into the past, and had to do an eight-month pilot study just to be sure her questionnaire and interview methods would be effective.

She is examining a catalog of known and possible cancer risks, including socioeconomic status; age of menarche; rate of body development; alcohol and tobacco use; major life events and “stressers” such as a pregnancy, illness or death of a parent or sibling; pesticide exposure; education; medications taken and illnesses survived.

For women in their 60s and 70s being diagnosed with breast cancer around the turn of the millennium, perhaps the stress of living through World War II is somehow involved, although that would not be simple to understand, let alone measure.

“I don’t think it gave them breast cancer,” Farren said. “The idea is it made them more susceptible later in life.”

As for environmental toxins, Farren noted, “I certainly think it’s possible there’s something in the environment that plays a role in breast cancer. But I don’t have a culprit in mind.”

Levien is adamant that no stone be left unturned. Her view, not uncommon, is that the female breast is a kind of “canary in the coal mine,” a sensitive chemical filter now showing the effects of unhealthy technology.

“Almost everything we’ve been doing since World War II has been killing us,” she declared.

Toxic Threat?

No evidence exists to clearly link breast cancer with chemical exposures in the U.S. population as a whole, and the same goes for Marin County.

The most definitive studies yet attempted are underway on Long Island, thanks to a congressional mandate and $26 million for 10 population-based studies of high cancer incidence in New York suburbs.

Elsewhere, a recent study of lifestyle factors and cancer by the Silent Spring Institute in Massachusetts ( found a correlation with only two environmental factors — lawn chemical use and dry cleaning — but the results were hardly definitive.

Levien warns that lawns can be maintained without toxins, and clothes don’t always have to be sent out for dry cleaning. She wants those factors checked out in Marin — along with a little digging to see what’s been buried in the high-priced ground.

Lifestyle changes

“We have a lot of landfills here. We want to know what’s in those landfills,” Levien said. “The military used this area heavily at one time. They dumped a lot of toxins. We definitely want to know where they dumped what.”

She advocates a halt to development, full-scale promotion of organic diets, dramatic cuts in pesticide use and less constant use of cell phones, since even those have been tagged as potentially dangerous (, albeit usually for brain cancer from using high-powered, older models rather than the digital phones favored in the Bay Area these days.

Levien has tacked up a big wall map of the county at the Cancer Watch offices, making the low-key commercial space just off Highway 101 look like a political campaign headquarters. Citizens are being asked to contact the organization about any toxic dumps, industrial polluters or other possible hot spots that even conceivably could have something to do with high cancer rates in Marin.

Multicolored pushpins, each denoting a suspected hot spot, are steadily multiplying as calls come trickling in and volunteers offer their own suspicions. Some are obvious: Navy installations in Marin City. Transmitters atop Mount Tamalpais. All that car exhaust along Highway 101.

Others are harder to pin down: Could there be toxins in the coastal fog from offshore dumping? Are dangerous herbicides being sprayed on Marin golf courses? Is there something in the water? What about household chemicals?

Dr. Angela Prehn, an epidemiologist with the Northern California Cancer Center, noted that the major problem with linking chemical exposures for breast cancer is that even the most common chemicals remain untested as risk factors in humans.

Unknown exposure

“Should I have been measuring my exposure [to chemicals] when I was a kid? Do I measure my exposure in my house now? How many bottles of Raid I go through? … there’s a billion different products they could be in. A lot of times you’re exposed to these sorts of environmental exposures and we don’t even know it. I mean, at work here they spray the lawns. And I don’t know what they’re spraying on the lawns. And if it’s a windy day and I’m breathing that in, is that bad for me? I don’t know.”

Activists and cancer survivors insist that this lack of knowledge can hurt us.

Marin resident Gail Womack said she once felt “very naïve” about the possible risks of pesticides and other “everyday chemicals we take for granted.” Then she was diagnosed with breast cancer at age 47.

“It was a total shock,” she said. “It was found on a mammogram. I was sure they had made a mistake.”

She finished chemotherapy last June and looks forward to completing surgical reconstruction by the end of summer 2000.

“I felt like I did everything right,” she said, adding that most of the other breast-cancer patients she encounters seem to be much like her, “young, healthy active women who have no history of this disease in their family, and who are totally not expecting this to happen to them.”

Statistical Significance

Epidemiologist Prehn at the Northern California Cancer Center has done one of the more definitive studies to date on Bay Area cancer rates.

It has done little to quell the concern.

Her straightforward approach was to look at the proportion of Marin women with known cancer risk factors and compare that to other counties.

In simple terms, the exercise was designed to find out whether the distribution of known risks, rather than something peculiar about Marin, could account for the high rates of breast cancer there, using easily accessible, existing data to find out.

Her study, co-authored by Dee West, also of the Northern California Cancer Center, was published in the journal Cancer Causes and Control in 1998. They used 1990 census block data to examine geographic variation in breast cancer rates for 25 Northern California counties, including Marin.

Weighing numbers

Results showed that while breast cancer incidence was nine percent higher in Marin than the other 24 counties, established risk factors and markers of high risk — such as number of children borne and socioeconomic status — appeared to account for the difference.

That means, they determined, more women with a high risk (as currently understood) for breast cancer live in Marin than elsewhere, but living in Marin County in and of itself does not seem to add to anyone’s risk.

Still, Prehn and West did not claim to have answered that lingering question of just what is causing the disease.

In the researchers’ own estimation, their simple exercise did not dig deeply enough to accomplish that.

“While this study shows that geographic variation in breast cancer rates in the greater San Francisco Bay Area may be explained by geographic variation in risk factors,” they concluded, “it did not directly address environmental causes of breast cancer. The results suggest that environmental risk factors specific to Marin County are not responsible for the locally elevated breast cancer incidence rates. However, the present findings do not imply that there are no environmental risk factors for breast cancer.”

Broadening scope

The research so far offers conflicting signals as to just what these environmental risks might be. But as of now nothing points to any factors that may be different in the Bay Area.

So Prehn and West advised broadening the scope of environmental studies to take in “widespread environmental exposures rather than an exposure specific to Marin County.”

Nationally, several other researchers have found that regional discrepancies in breast-cancer rates can be explained pretty well by known risk factors and demographic descriptors.

But numbers do change. The latest NCCC cancer statistics show Marin’s rates to be even higher, relatively speaking, than the rates used in the 1998 study.

And 10-year-old census data may no longer be accurate, particularly for dynamic regions like the Bay Area.

Although the Prehn study has not satisfied everyone by a long shot, a local physician said the results fit well with his understanding of what is causing his patients’ cancer.

“The data so far just don’t show there’s any environmental substance or other factor that could account for Marin breast cancer rates,” said Dr. Timothy Crowley, director of the Breast Cancer Institute at Marin General Hospital (

Looking for possible toxins in Marin, perhaps from abandoned Navy facilities or manufacturers, is worth doing, Crowley said.

He just wants a little perspective. An environmental culprit in breast cancer is “worth looking for, but one doesn’t need to look any harder in Marin than in other communities. There’s no particular reason to suspect there’s been more toxic contamination in Marin, and in fact I suspect there has been less.”

Digging Deeper

Merely massaging some statistics is hardly what is being demanded in Marin County.

Evidence of the prevailing sentiment came this past February, when a big crowd turned out for a local health department meeting to establish the early contours of a study plan.

All sought more ambitious research than has been done before, to look deeply into the Marin County environment and demographic facts. The goal is a scrutiny of the community’s health status on par with the inquiry being conducted in Long Island — on a slightly smaller scale.

Nevertheless, Marin health director Rubin found no fault with Prehn’s demographic study.

“I’m not dubious about anything,” she said, instead professing what seemed to be an aggressive state of neutrality.

“I’m assembling the ability to analyse the data,” Rubin said, outlining a step-by-step “linear plan” to find out everything there is to know about breast cancer, and perhaps other forms of cancer, in Marin County.

Under Rubin’s plan, the health department is raising money to hire an epidemiologist, and then will assemble in one central place all data presently available. The final step is to undertake new studies that will plug gaps in that existing database.

Throughout the process, Rubin wants to be sure community voices are heard at every step. Prehn’s statistical work may quell some fears of a “hot zone” of breast cancer in Marin, but the unease remains.

“It’s kind of a mystery,” said Marin resident Susan MacLeod, who detected a malignancy in November and had a lumpectomy in December.

The 46-year-old mother of two worries most about what might be lurking in water, perhaps something no one is testing for.

“It’s not like we are being sprayed every day by cropdusters,” she said. “I don’t think Marin has a lot of air pollution. But everywhere you turn is something that could be dangerous.”

Search for funds

Nancy Rubin, the Marin County head of public health, promises to get to the bottom of the mystery as best she can.

“I don’t think anyone has drilled down deep enough to answer a lot of the questions the community has been asking,” she said.

One of her first steps was to seek a $130,000 budget appropriation from the Marin County Board of Supervisors for the initial epidemiology studies, and to establish a partnership to carry out the study with the University of California at Berkeley’s School of Public Health.

Another $250,000 has been earmarked by the U.S. Centers for Disease Control and Prevention. And the search is on for more state and federal funds.

The money may not be easy to come by, but this is Marin. Wealth and political clout go hand-in-hand.

If you’re poor, black and live in San Francisco, your experience will be very different.

NEXT: Plague of Neglect

Carl Hall is a San Francisco Chronicle science writer and the San Francisco Newspaper Guild union rep.

2 thoughts on “Breast Cancer’s Cause & Controversy

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