Cancer cluster in N.C.? A mother fights for answers
MOORESVILLE, N.C. — The mystery began more than two years ago with a pea-size lump behind the left ear of Susan Wind’s oldest daughter, Taylor, then 16.
A doctor told them it was “nothing to worry about,” likely triggered by teenage hormones. But Wind was unconvinced, and eventually, through testing, Taylor was diagnosed with papillary thyroid cancer, which is less common in children and would require surgery.
The journey to restore Taylor’s health would lead to Wind uncovering an anomaly lurking in Mooresville, a fast-growing lakeside suburb of Charlotte: On Wind’s street alone, three people had thyroid cancer, while two others had thyroid tumors, she learned.
As she began tracking case after case in her community, Wind believed that what she was seeing was no coincidence, and that something in the environment could be to blame.
Wind raised $110,000 to get a team of scientists from Duke University in Durham to test the groundwater, soil and air, and collect information from residents in the hope of identifying a possible connection. The full report is still months away, but what researchers find could provide a breakthrough for what’s happening here.
In 2018, as part of an analysis of the state’s cancer registry data, the Iredell County Health Department confirmed that two ZIP codes in the Mooresville area, including one where the Wind family lived, had 110 observed cases of papillary thyroid cancer from 2012 to 2016 — more than double the number expected.
“I want to know why everyone is getting cancer, and what do we all have in common,” Wind, 46, said.
Mooresville isn’t the only community in which residents unnerved by seemingly unusual cancer rates are struggling to find answers. About 1,000 suspected cancer clusters — places in which a higher than normal type of cancer is concentrated — are reported to state health departments each year, according to the American Cancer Society. But studying them is challenging, with results often inconclusive, dubious or failing to meet the right criteria to satisfy various health agencies.
About 13 percent of more than 560 suspected cancer clusters examined in the United States from 1990 to 2011 were considered “confirmed” in a 2012 study by Emory University epidemiologists.
The Centers for Disease Control and Prevention gathered public input last summer for how health departments can best respond to possible cancer clusters. (Updated guidelines are expected to be released in 2021.)
Those who responded to the CDC expressed an urgency to investigate potential cancer clusters that have not yet been confirmed. Among them were an Indiana woman whose 13-year-old was diagnosed with a brain tumor along with three other children within a one-block radius; a New York woman being screened for cancer and whose friend and dog a few blocks away had been diagnosed; and another commenter who did not give a location but said they regretted moving to a place that they later learned was home to a potential cancer cluster.
Andrew Olshan, an epidemiologist at the University of North Carolina who co-authored recommendations last July on how to study the growing thyroid cancer rate in North Carolina, said requests should be scrutinized.
“It’s extremely challenging for the state and the CDC and others to really go through this and say, ‘Aha, we’ve found the cause of these cancer cases,'” Olshan said. “But they deserve answers on the off chance we can learn more.”
The problem with cancer clusters
The federal government defines clusters as a “greater-than-expected number of cancer cases that occurs within a group of people in a geographic area over a period of time.”
Determining whether it’s mere chance or of pressing public concern can be a tall order for health officials.
Still, health experts say, there are general parameters: All of the cases in a cancer cluster must be the same type, the cancer must be limited to a specific area — for instance, a ZIP code or a workplace — and the diagnoses must have been confirmed within a given period. This accounts for the fact that some cancers can take years or decades to develop.
Health officials review cancer rates to see if the number is in fact higher than what is normally reported in that area. In addition, they note the demographics of the patients; that way they can find anomalies, like children diagnosed with a cancer that typically affects adults.
Studies however, can cost millions of dollars, according to Dan Fagin, the director of the Science, Health and Environmental Reporting Program at New York University.
“Health departments don’t want to investigate because they’re expensive and they often have ambiguous results and they can make people really upset,” Fagin said.
The first two cancer cluster investigations in the United States to determine an association between high rates of cancer and environmental pollution were in a Boston suburb in 1984 where there was an outbreak of childhood leukemia, and in Toms River, New Jersey, where the rate of childhood brain and central nervous system cancers was three times higher than expected.
In his 2013 book, “Toms River: A Story of Science and Salvation,” Fagin reported that 90 children, including some as young as 6 months old, were diagnosed with cancer in the town from 1979 to 1995.
A five-year, $10 million epidemiological study concluded the cancer was related to environmental pollution, but there was not enough evidence for officials to conclusively say that toxic chemicals from two nearby waste dumps had tainted the water supply to a level that compromised the community’s health. But in 2002, the companies associated with the pollution, without acknowledging liability, settled in court with dozens of families.
“You could think of Toms River as a fluke, but I think the most likely explanation is that Toms River is a warning,” Fagin said. “Cluster investigations are like the fire marshal that comes into the house after it’s already burned down. What we really need are fire inspectors who look for problems before they do their damage.”
“Trevor’s Law,” which then-President Barack Obama signed in 2016, requires the federal government to track cancer clusters around the nation. President Donald Trump has approved the release of $1 million for the CDC to update its guidelines for how to conduct future investigations, although that’s still another year away from completion.
Trevor Schaefer, an Idaho native who inspired the law after surviving childhood brain cancer, is frustrated with how slow progress has been.
“In the interim, a lot of children and adults have and will continue to get diagnosed with cancer and many will not survive,” he said, “and those that do will forever face chronic health challenges.”
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A search for a source
When Wind, a cybersecurity consultant, shared her daughter’s thyroid cancer diagnosis on social media, she was surprised to hear that others in Mooresville were going through a similar situation.
“I just started seeing all these people had cancer, which always lived in the back of my mind, ‘Gosh, there’s a lot of cancer here,'” Wind said. “But you don’t know if it’s here or everywhere.”
Thyroid cancer develops in the tiny, butterfly-shaped gland that regulates the body’s metabolism, and while people of any age can get it, it is more commonly diagnosed in women in their 40s and 50s, according to the American Cancer Society. The cancer, if treated, has a 98 percent cure rate.
Doctors treating Taylor Wind’s thyroid cancer at the Wake Forest Baptist Medical Center in Winston-Salem confirmed they had seen other cases of it in her area. They referred Wind to a Duke University chemist, Heather Stapleton, who told her an investigation was her best shot at getting answers — but she’d need at least $50,000.
Within months, Wind had organized a 5K fundraiser and collected more than double the minimum needed for the study.
The Iredell County Health Department had begun looking into cancer rates, including for thyroid, in late 2017 after a resident requested a report. The following spring, Wind caught the attention of officials when she spoke with local media about the seemingly high cases of cancers she had come across.
In June 2018, after analyzing the data, health officials confirmed what she was tracking anecdotally in their county of about 175,000 people: The state’s cancer registry observed 191 cases of thyroid cancer from 2012 to 2016, almost double what was expected. Statewide, 11.6 thyroid cancer cases were diagnosed per 100,000 people, while in Iredell County the rate was 21.8 cases.
And in two Iredell County ZIP codes that include Mooresville, where officials expected about 46 cases of thyroid cancer, they observed 110 cases.
State health officials, however, make clear that the numbers don’t identify a source for the higher rate of cancer. Other factors exist: Does cancer run in the patient’s family? Does the person smoke or have diabetes? Do they have access to health care and can get screened?
“Because cancer is common, cases might appear to occur with alarming frequencies within a community even when the number of cases is within the expected rate for the population,” state health officials wrote in their assessment.
Iredell County officials also point out that thyroid cancer rates in general have been increasing throughout the state as well as across the country. In fact, the study also found 11 other counties in North Carolina with “significantly higher” rates of thyroid cancer.
Prominent cancer researchers in the publication “Cancer Epidemiology and Prevention” noted in 2017 that thyroid cancer, once relatively rare, is now the eighth most commonly diagnosed cancer among women worldwide — as access to testing becomes more common and available. For papillary thyroid cancer, which almost 90 percent of the cases in southern Iredell County fall under, the known risk factors are obesity and childhood exposure to certain radiation.
But that doesn’t mean those are the only possible causes. Research suggests there could be a relationship between the increased risk of thyroid cancer and chemicals found in flame retardants, which are used in building materials and other household products, and radon, a naturally occurring radioactive gas that is the second-leading cause of lung cancer behind cigarette smoking.
The presence of coal ash
On the edge of Lake Norman, the largest man-made lake in North Carolina, there are two power plants near Mooresville: the McGuire Nuclear Station and the coal-fired Marshall Steam Station, both owned by one of the largest energy companies in the country, Duke Energy.
State health officials have found no evidence of increased radiation coming from the nuclear plant. The Marshall station, meanwhile, produces coal ash as a byproduct of powering the facility.