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Required Reading #2 - Seattle’s Cancer Mystery f This...

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Unformatted text preview: Seattle’s Cancer Mystery f This region ranks worst nationwide 1n breast cancer and near l l worst in other cancers, and the fault lsn ’t just in our genes. j —J by Francesca Lyman illustrations by Katherine Streeter JUNE 2006 l 99 A IV“ ofoed is still mystified. Her life had been far wholesome to deserve any part in this grim . A lifelong Washington resident, she’d had a ure-book childhood on an 8o-acre farm on 'dbey Island, where she and her family churned their own butter, baked their own bread, and dined on fresh organic meals from their own fruit ; trees, vegetable garden, and free-range chickens and beef. Then, at age 39, with three children of l her own, she found a lump in her left breast. It proved to be an 8-centimeter-wide invasive tumor. The cancer had spread to her lymph nodes. 100 I senne METROPOLITAN “When you’re diagnosed you start to ask yourself, ‘What did I do to get this?” says Kofoed. She knows she'll probably never learn the precise reasons, but she wonders whether it was a gene or some mysterious environmental ' factor that marked her for this dread disease. Kofoed doesn’t fit any classic medical profile. Her immediate family had no history of breast cancer. Starting at age 24, she'd given birth to three children, eliminating her from the higher- risk group of women who defer or avoid child- birth. She wasn’t a smoker and never worked late nights, two other risk factors. Her early home surroundings raised no red flags. But then she considered lake Forest Park, where she has lived for the past 20 years, and began to wonder: Eight other women in her immediate neighborhood also had breast cancer. Two of them have since died. Was it jet fuel wafting up from Kenmore Air’s small seaplane harbor? she asked herself. The growing traffic around the lake? Something in the milltown of Everett, where she was born, or leaking over from the nearby Whidbey Naval Air Station as she was growing up? Kofoed moved beyond “Why me?” and started asking, “Why us?” How could this be happeningin the shadow of Mount Rainier, in a haven for the health-conscious and nirvana for nature lovers, where kayaking outfits double as office attire and eagles Windsurf the thermals over city neighborhoods? She learned that wholesome stereotypes don’t necessarily translate into better health. Washington State has the highest rate of breast cancer of all 50 states, 18 percent higher than the national rate. AmongWashing'ton counties, King County has the fifth-highest age-adjusted rate: 195 new cases a year per 100,000 residents, 26 percent above the national average. Kitsap, Pierce, and Snohomish Counties also have high rates. The Puget Sound region ranks highest in breast cancer among all population centers inventoried by the Centers for Disease Control and tops the national average in every other major cancer except colon, Is it something in the water or air, in our diets or habits, our Nal— gene bottles or lattes? What demographic, geo graphic, or environmental factors might explain this epidemic? NATURE AND NURTURE Everybody knows someone—a mother, daugh- ter, sister, friend, colleague, perhaps even a brother or father—who’s been diagnosed with breast cancer. It is the most common life- threatening cancer among US. women; the ‘ American Cancer Society projects that some ”Ian's 214,640 new cases will be diagnosed this year, 4,000 in Washington State, plus 61,980 nonin- vasive in situ tumors. They also project that 41,430 patients will die ofbreast cancer, includ- ing 770 Washington women. Non-Latina white women have the highest rates of breast can» cer. But Latina rates are rising, both nationally and in Washington State. The percentage of African-American women diagnosed with breast cancer has declined in recent years—but the share dying from it is rising, partly because oflate diagnoses and lack of access to mam- mograms. The reasons for these trends are complex and somewhat mysterious. Breast cancer is what scientists call a multifactorial disease; a variety of genetic, environmental, and lifestyle factors may play a role in the DNA damage that causes it. Dr. Michael Hunter, a radiation oncol- t 1 r , l r New cases per 100,000 residents. 2002 ALL CANCERS invasive only I KING COUNTY. PUGET SOUND REGION ogist at Evergreen Hospital in Kirkland, looks first to the best-confirmed risk factors. starting with family and personal medical history. Hav- ing close relatives with any cancer raises the odds; breast cancer in a mother or sister dou- bles the likelihood. But as Hunter notes, “the vast majority of patients don’t have a family history of the disease." The American Cancer Society pins only 3 to 10 percent of the risk on genetic factors. Basic reproductive history also plays a role. Early menstruation, late menopause, and defer ring or delaying child-bearing all boost the amount of estrogen circulating in a woman’s body, which according to the American Cancer Society contributes to breast—cancer risk. Early pregnancy reduces that risk somewhat, but Seattle now ranks well below the national aver- age in teen pregnancies (a good thing in many Cancer Country COLON/RECTUM WASHINGTON Source: CDC National Center r Chronic Disease Prevention and Health Promotion LUNG/BRONCHUS UNITED STATES other regardsv. The birthrate among King County women aged 20 to 24 fell 16 percent between 1997 and 2003. Metropolitan Seattle- Tacoma-Bremerton also has the fifth-highest percentage of single, college-educated young women among major metropolitan areas and the nth-highest share of 25»toe34-year~olds with college degrees—and such women are more likely to breed late or not at all. THE "YUPPIE FACTOR" But Julie Kofoed, with three kids, is living proof that breeding isn’t destiny; all these reproduc- tive factors together account for just 25 to 30 percent of breast cancers. That leaves another halfor more unexplained. And that’s where a wide range of what are broadly called “environ- mental” factors, from diet and lifestyle to toxic exposures, come into play, even for those with the strongest genetic predisposition. Pioneering studies by UW genomics profes- sor Mary-Claire King show that women carrying inherited mutations in the genes BRCAi or BRCA2 have a more than 80-percent lifetime risk of contracting breast cancer. But whether or not even these women at highest risk get the dis- County data are available only for invasive cancers together with noninvasive [those that i haven't spread beyond the breast tissue]. BREAST invasive/noninvasive BREAST Sources: Washington State i Cancer Registry; CDC | JUNE 2006 I 101 ..__a.__._-_t_...a.__..‘—x..__.... . ... Suspected culprits in this region’s breast cancer epidemic Gender, Age, and Heredity Men can develop breast cancer, but about 99 percent of cases occur in women. Risk increases A greatly with age. Five to 10 percent of cases are due to inherited gene mutations; having close relatives with breast or ovarian cancer is a strong marker. Childlessness and Hormone Replacement Bearing no children, or none until after age 30. may increase risk slightly, Likewise early menarche and late menopause Breast-feeding may confer protection—the longer. the better. Hormone replacement therapy, or at least estrogen and progesterone combined. increases risk; estrogen alone may be safe. though one new study suggests otherwise for women who've had hysterectomies. Oral contraceptives may increase risk. Vitamin D/Sunshine Deficiency In sunlight, skin manufactures Vitamin D, which may protect against certain cancers by preventing cell overgrowth. British researchers recently found an enzyme in breast tissue that converts Vitamin D into a cancer-fighting compound. Radiation Ionizing radiation—such as X-rays and much i more powerful CT l\ scans—is known to cause cumulative §\ // chromosomal damage and a very small share of breast cancers Mammograms. which deliver low doses, are safer for postmenopausal than for young women, but there's a rising clamor for safer detection methods. Alcohol Consumption One drink a day confers a 10 percent higher risk. two drinks 25 to 70 percent. Mouth. throat, and esophageal cancers also increase with drinking. 102 I senrce METROPOLITAN ease depends on additional factors, such as how much they exercise and what they eat. “It was a surprise, but a source of hope, to learn that fac— tors over which we have some control made a difference in the age at which these highest—risk women developed breast cancer," writes King. King’s work also confirms that today’s cancer risks dwarf those of the past. Women born before 1940, her study subjects’ median birth year, had a 24 percent chance of developing breast cancer by age 50; women born after 1940 had a 67 per- cent chance. Something had changed between the pre- and postwar periods. For King. “This suggests that even when there is a strong genetic risk present, environmental factors play a vital role in determining when cancer occurs." “The link between environmental exposures and cancer is not getting the attention it deserves from cancer researchers because of all the excitement about the Human Genome Proj» ect," says Dr. David Carpenter, a former dean of the State University of New York (SUNY) at Albany’s School of Public Health. The success ful effort to map the genome “is exciting," he adds, “but that is not telling us enough about the initiating events of cancer—which are not genetic but environmental." Many of these influences fall under what's sometimes called the yuppie factor—the wages of affluence. In China the slang term for breast cancer is “rich woman’s disease"; Jane Plant, chief scientist of the British Geological Survey, notes in her book Your Life in Your Hands that when Eastern people adopt Western diets and lifestyles, the disease’s incidence rises. Epidemiologist Kathi Malone, a research pro» fessor at Seattle’s Fred Hutchinson Cancer Research Center, notes that affluence also leads to greater education, “and that correlates with never having had a child or having a child later in life." It brings greater use of hormone replace- ment therapy to relieve postmenopausal symp- toms, thus raising estrogen levels and breast cancer risk. This correlation has been charted in two renowned breast cancer hot spots, Marin County, California, and Long Island, New York, where the demographics of the disease have been closely studied. Malone says detailed stud- ies of Seattle women's reproductive habits are only now under way, but that hormone replace- ment therapy is even more widely used here than in those hot spots. But though She concedes that “it feels like [breast cancer] has been at epidemic propor- tions for some time now,” Malone adds a caveat: “Part of the increasing incidence we are seeing in Western Washington is due to screening." More wealth and education mean more access to medical services including mammograms, so more cancers get diagnosed. Then again, mam- mogram radiation is another risk factor: One 1998 report (before the advent of digital mam- mograms somewhat reduced radiation levels) estimated that a mammogram at age 33 con- ferred a 1-in-1,112 risk of later breast cancer. Alcohol consumption, which often increases as women become more affluent, educated, and emancipated, has also gained new recognition as a risk factor. “Alcohol appears to increase estro gen levels,” says Malone, “and some studies have shown a relatively high rate of estrogen increase even with a moderate increase in drinking.” The state Department of Health reports that both women and men in Washington drink more alco- hol than the national average. And Washington has an above-average share of women (though not men) who are classified as “heavy drinkers"— consuming more than five drinks at a sitting. IS IT IN THE AIR? But why do several rural Eastern Washington counties where the yuppie factor is not so pro— nounced have breast cancer rates even higher than Pugetopolis'? (Wheatgrowing Garfield’s is 71 percent above the national average.) Dr. Juliet Van Eenwyk, an epidemiologist with the state Health Department, notes that these counties’ populations are so low that small spikes can have outsized statistical effects; any underlying causes remain unknown. Facing these uncertainties, many breast can- cer advocates look to environmental causes that aren't associated with lifestyle choices. They complain that scientists “continue to dis» miss environmental factors and harp on demo» graphics,” in the words of Jeanne Rizzo, director of the San Francisco—based Breast Cancer Fund. “This generation is getting sicker rather than healthier, and we need to understand why." In fact, says Dr. Robert Hiatt, a professor of epidemiology and biostatistics at the University of California at San Francisco, researchers have long hypothesized that chronic exposure to a number of widespread and persistent industrial chemicals may explain the increase in various cancers in industrialized countries. Especially breast cancer, adds Hiatt, “since there’s such a vast disparity in breast cancer rates between the US. and Europe and Southeast Asia—by a mag- nitude of as much as fivefold. And women are much the same biologically. It can’t be genetic." Studies have found that when women in devel— oping countries, particularly in Asia, migrate to industrialized areas, their cancer rates rise within a generation. They may consume more alcohol, meat, and dairy products, breathe dirtier air, and be exposed to more pollutants-all possible fac- tors in China’s “rich woman's disease.” One local environmental factor is noncontro— versial: sunshine, or its absence. “My favorite hypothesis is the lack of sunlight here in the Pacific Northwest, which has been linked to lack of Vitamin D,” says epidemiologist Van Eenwyk, laughing grimly. “We know that people get less Vitamin D because of less sun, and Ore- gon is usually right up there in the [cancer] sta- tistics with us." The baleful effects of automotive air pollution are also undisputed. Benzene is classified as a “probable risk factor" for breast cancer, the second-highest risk category; benzo(a)pyrene is a potent confirmed mutagen and carcinogen. And these are just two of many polycyclic aro- matic hydrocarbons (PAHs) and other toxic com- pounds found in gasoline fumes and exhaust. “Seattle’s air pollution is very low compared to the typical Eastern city,” says Elena Guilfoil, air toxics coordinator for the state Department of Ecology, “and Los Angeles’s car exhaust just dwarfs Seattle’s.” Nevertheless automobile use, the main local source of air pollution, keeps ris- ing; the Sightline Institute (formerly Northwest Environment Watch) reports that miles driven have more than doubled in the Puget Sound region, from an average 36 million perweekday in 1980 to 80 million in 2004. And the problem isn’t just Seattle’s: Surprisingly high levels of tailpipe toxics turn up in the suburbs. For example, in 2002 state monitors found mean readings of ben- zene and other pollutants in leafy Lake Forest Park (where Julie Kofoed lives) that were about 50 percent higher than readings on Beacon Hill and in heavy-industrial Georgetown, and nearly twice as high as those in SeaTac. lake Sammamish and Maple Leaf also measured higher than SeaTac. But, sighs Guilfoil, the air-toxic monitoring was discontinued for lack of funding, so what we have is the “best snapshot” we’ll get. PLASTIC HORMONES Other researchers look to the thousands of new synthetic chemicals developed and widely deployed since World War II. Many are “xeno- estrogens," chemicals that behave like estrogen, including ingredients in various cosmetics, lotions, and other bodycare products; the ubiq- uitous plasticizer bisphenoI-A, used in water bottles and food containers; PAHs in gasoline exhaust; long-lasting bioaccumulative toxins such as polychlorinated biphenyls (PCBs), once used in electrical transformers; and flame- retardant PBDEs, which accumulate in fish. Most fish and shellfish are rich in omega-3 fatty acids. ”I which can reduce risk of heart disease and stroke. H slow mental decline. and promote healthy pregnancies. But many contain mercury and/0r bioaccumulative toxins such as PCBs. PDBE flame retardants. and dioxins. Safe seafood guides are available. Dairy Products Breast cancer is much rarer in the Far East. where people consume less milk. Fat-soluble pollutants can accumulate in milk; low-fat dairy products may lower risk. Many nonorganic U.S. dairy products contain genetically engineered recombinant bovine growth hormone, which boosts the natural hormone insulin growth factor-1. Several studies link increased IGF-l to breast cancer. Household Toxins Insect and weed killers. cleaners, flame retardants. paints, solvents. wood finishes, plastic containers. nail polishes. and many . other common household products contain known or suspected carcinogens. according to studies by the Silent Spring Institute. Airborne Toxins and Smoke 0 Factory and tobacco . smoke, gasoline fumes, and auto exhaust all contain polycyclic aromatic ’ hydrocarbons [PAHSL linked to breast cancer. Toxic Waste Sites Researchers at the Department of Preventive Medicine and Community Health. at the New Jersey Medical School. in Newark, found 650 percent more breast cancer in counties with toxic-waste dumps. This state has 47 of the EPA‘s top-priority hazardous-waste sites, including Seattle's lower Duwamish River and the 586-square-mile Hanford site, containing both concentrated toxic wastes and low-level nuclear waste with a half-life of 24,000 years. Night Light/Circadian Disruption Several recent studies suggest that nurses. flight attendants. and other night workers suffer increased risk of breast cancer because of depressed levels of the hormone melatonin. June 2005 I 103 i i i Seattle’s Cancer Mystery A recent review study by Kate Davies, a pro- fessor of environment and community at Seat- tle’s Antioch University, suggests that environ— mental toxins contribute to Seattle’s and Washington ’5 above-average rates of breast cancer, melanoma, and other cancers, as well as childhood asthma and ADHD. “It’s not that our environment is necessarily more contaminated than any other place,” says Davies, “but the environmental factors are clearly playing a role here as elsewhere." Watchdog groups are trying to determine how contaminated local women themselves are. Sightline tested breast milk from 40 women in Seattle, Oregon, Montana, and British Columbia, and found PBDEs in every sample. The Washing— ton Toxics Coalition also released the results of its “body burden” study measuring a variety of toxins in Washington State residents and found that all had at least 27, some as many as 40, of these chemicals in their bodies, from heavy metals like arsenic, lead, and mercury to Teflon, pesticides, and other synthetics, including the outlawed but persistent PCBs and DDT. “Many of the chemicals do not break down or do so slowly, and therefore build up in human bodies and breast milk, the Toxics Coalition concluded. Dr. Carpenter of the University at Albany thinks salmon consumption may offer a clue to our high rates of cancer and other diseases. He’s found concentrations ofdioxins, PCBs, PDBEs, and various pesticides in farmed salmon 10 times higher than those in Alaskan wild salmon. And, he adds, “wild salmon from Puget Sound have been reported with levels compa— rable” to farmed fish. He urges eating European farmed salmon no more than once every five months, local chinook no more than once a month, and local coho and sockeye no more than twice a month. Kotoed still wonders why it hit her, and how “to j prevent this from happening in the first ptace." \ ‘J The effects of toxic exposures may depend on when those exposures occur. New research is honing in on particularly vulnerable life stages, such as fetal development, infancy, and puberty. Last year researchers a...
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