It's not clear that this inspiring picture is ever accurate; at science's leading edge, where new things are happening, the picture is always more complicated.
In 2002, the Arizona Department of Health Services declared a leukemia cluster in Sierra Vista, a booming military and ranching town 90 miles southeast of Tucson (see "Cancer Wars," Feb. 12, 2004). Between 1997 and the end of 2003, 12 children with ties to Sierra Vista were diagnosed--three times the expected number for a town of 40,000. Two of those children have died. Another Sierra Vista resident, a 23-year-old woman who'd lived in the town for 21 years, also died of leukemia in 2003, after being sick for about a year. Only children under the age of 14 are included in Arizona's childhood leukemia statistics, so her case is not counted in the cluster.
The outbreak has apparently ended, or at least paused: No new cases among children who live in the town have been reported since 2003, when there were three. (Another child, Kellie Durkit, who has visited her father in Sierra Vista but lives in Phoenix, was diagnosed in 2004, and the Arizona Department of Health Services counts hers as the 13th case.)
From the beginning, the outbreak in Sierra Vista has been associated with the famous leukemia cluster in Fallon, Nev. Fallon has the unfortunate distinction of having the worst childhood leukemia cluster ever recorded; some say it's the worst known cancer cluster of any kind.
Between 1995 and 2005, 17 children with links to this small (population 7,500, as of the 2000 Census) town one hour east of Reno were diagnosed with one of the two main types of childhood leukemia, acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL). This equates to a leukemia rate roughly eight times normal. Three of those children have died.
That's just the official count, though. According to a Fallon parents' group, the actual numbers are 25 children diagnosed and five dead, which puts the rate at more than 10 times what's expected. Which cases you count, and which you exclude, is of critical importance in the world of disease clusters.
Using the lower, official count, researchers writing in the journal Environmental Health Perspectives in 2004 calculated the odds of the Fallon cluster being due to chance at 232 million to one.
Fallon has also had at least one case of childhood rhabdomyosarcoma, a soft-tissue cancer that occurs in just four out of a million children in any given year; Sierra Vista has had two. Childhood rhabdomyosarcoma, although much rarer than childhood leukemia, has been linked to a gene associated with leukemia.
On the face of it, the two towns have much in common beside their extraordinary number of sick children. Both are home to military air bases; both are in the desert; both had been experiencing prolonged drought; both are near old tungsten mines. (Fallon also has an active tungsten carbide processing plant within the city. Tungsten is a heavy metal that's used to make filaments for lightbulbs, brake linings and missile nose cones, and in alloys to harden other metals.) The similarities between Fallon and Sierra Vista, and between them and two other towns--Elk Grove, Calif., and Hoisington, Kan.--that also have excess cases of childhood leukemia and rhabdomyosarcoma suggest that these towns might hold clues to the cause, or at least into one possible set of causes, of a deadly and increasingly common childhood disease.
To someone who is interested in solving the mystery of leukemia, concurrent epidemics present a unique research opportunity, and the ultimate possibility of protecting children from exposures that increase their risk of a dreadful disease. Forty years ago, leukemia was a death sentence. Now, with aggressive treatment, about 80 percent of its victims recover. The chemotherapy protocol, however, is gruelingly toxic. It makes the children extremely ill and vulnerable to infection and can cause irreparable damage to their hearts and brains.
"I was just over in Elk Grove," says Mark Witten, a biomedical researcher at the UA who has been working on the clusters since 2002. "I went to see a child who'd just relapsed, and oh God. You see what this disease does to these kids--it keeps you going."
The cluster problem also piques researchers' basic curiosity, the desire to get to the bottom of things, to solve a scientific mystery.
"At this point, some aspects of leukemia are very well understood, and one of these days, someone is going to solve it," says Paul Sheppard of the UA's Laboratory of Tree-Ring Research, Witten's research partner on the project. "It's a big one, and whoever puts all the pieces together will get the Nobel Prize. No question."
He laughs. "That won't be us, of course. But being able to add a piece or two to a puzzle like childhood leukemia--it's exciting work."
Over the last four years, Witten and Sheppard have spent thousands of dollars of their own money and driven untold tens of thousands of miles around Arizona, Nevada and California on the trail of the cause--or causes--of the clusters.
Based on data indicating high levels of tungsten in all four towns, plus preliminary work by Witten in which he accelerated the growth of human leukemia cells by exposing them to ground tungsten ore, and evidence from a 2003 Centers for Disease Control and Prevention investigation of Fallon that found high levels of tungsten and other metals in the water and people's bodies, they've gone after tungsten exposure as a possible cause.
They've attacked the problem from two directions: They're using tree-ring coring and other techniques to look for tungsten and other metals, and especially for rising levels of potentially toxic substances, in all four towns. (They're also trying to pinpoint the sources of those metals.) At the same time, Witten has been doing basic laboratory research on the biological effects of exposure to tungsten and other metals with which it's associated.
They're beginning to get results in the form of peer-reviewed publications and corroborative findings from other researchers. In January, Sheppard, Witten, Fallon physician Gary Ridenour and one other author published their findings on the high levels of airborne tungsten and cobalt in Fallon in comparison to other Nevada towns. Last month, Witten announced the results of a study done in his UA lab that showed that exposure to tungsten, in combination with arsenic--which also occurs in both Fallon and Sierra Vista--caused changes in genes associated with leukemia in mice. In addition, the study found that tungsten and arsenic, in combination with cobalt, which is used in the hard-metal processing plant in Fallon, produced genetic changes associated with brain cancer.
These findings are strengthened by results from an independent group of researchers that's been investigating the biological effects of tungsten and cobalt for the U.S. military. They found that a combination of the two caused rhabdomyosarcoma in 100 percent of exposed rats.
These are just three more small pieces, Witten says, which need to be replicated and taken further. Sheppard's latest environmental findings also look strong, but are still in process or under review. Still, Witten is more convinced than ever that the government should be protecting children from breathing tungsten. Although they've found less airborne tungsten in Sierra Vista than in Fallon, he and Sheppard identified two hotspots in their first round of air-monitoring and tree-core analysis.
Witten suspects that the Sierra Vista hotspots may be natural mineral outcroppings that could be capped or dug out.
"Our data is preliminary, but we're sort of in a hurry on this. I've called Gov. (Janet) Napolitano's Southern Arizona office trying to get somebody, anybody, to come in and survey the town to see whether something could be done," says Witten.
"What we're talking about is something that may be a threat to the health of children. I see no reason to wait."
The urgency and enterprise with which Witten and Sheppard have worked contrasts sharply with the doings of the government agencies charged with protecting public health.
Last May, after many requests, and more than a year after announcing that it would do bio-monitoring in Sierra Vista, a research team from the CDC came to town to take samples of blood, urine and mucous cells from case families, as well as a number of "matching" control families. Those samples were then overnighted to CDC labs in Atlanta to be analyzed for the presence of known carcinogens and other substances, including tungsten. Cochise County's epidemiologist at the time, Dr. Gary Spivey, said that results might be back by fall 2005. The results did not emerge, but were promised in the winter, and then spring.
The CDC's last estimate for the release of their findings is August. The county's information officer says that the reason given by Atlanta for the latest delay was that the county has changed epidemiologists.
The latest foot-dragging by the CDC is part of a pattern familiar to people who monitor environmental and public-health investigations: Studies by government scientists seem to take forever.
Witten and some families of the patients tried to get the CDC to investigate the cluster several years ago, but the agency refused, saying that it had to be invited by the state health department. ADHS, in turn, declined to invite the CDC until results emerged from the full-scale cluster investigation in Fallon, on the grounds that the clusters were similar, and any results might be pertinent. As it turned out, the CDC's report on Fallon, released in February 2003, stated that the agency did not "discover an environmental exposure that explains the cluster of leukemia in children in Churchill County."
Several facts leapt from the Fallon data, however: extremely high levels of arsenic and tungsten in Fallon's water and in the bodies of both children and adults. In some children, the CDC found up to 18 times the tungsten exposure that's considered normal--plus moderately elevated exposures of other metals, including uranium and cobalt.
Much to Witten's disappointment, only four case families were tested when the CDC finally got to Sierra Vista. A number of families with sick children had moved away and were excluded by the CDC on the basis that they would have developed different exposures while living elsewhere. (A Tucson advocacy and support group, Families Against Cancer and Toxins, or FACT, offered to fly them in for testing, but the CDC refused to include them in the study.) The agency also wanted to exclude a family still in Sierra Vista that had lost a child to leukemia, on the grounds that the child was dead. FACT appealed that decision, and the surviving family members were allowed to participate in the testing.
Two families still living in the area refused to be part of the study, citing their belief that nothing would come of it. One of these families, the Durkits, have had two daughters stricken by leukemia. In 2001, Jessica Durkit, then 2, was the seventh child in the Sierra Vista cluster, and the willingness of her parents, Dale and Kelley, to ask questions in public helped bring attention to the outbreak and put pressure on officials to investigate. While they were still waiting for the CDC to come, incredibly, Dale's daughter Kellie, then 11 and living with her mother in Phoenix, was diagnosed in 2004 with the same type of leukemia as her half-sister. To have leukemia strike the same family twice is nearly unheard of: It's the most common cancer of children, but it's still a rare disease. (The family says both girls are now doing well.)
Loss of faith in government health agencies is not an uncommon reaction among the families of disease-cluster victims. Each family copes with the chaos and fear in its own way: Some parents wash their hands of the whole thing. Some others go to war.
In Fallon, the government's handling of the cluster radicalized a number of parents, among them Matt Warneke, a chef who has moved back and forth between Fallon and Sierra Vista--he now lives in Sierra Vista with his wife and three children--and Floyd Sands, who now lives in Pennsylvania. Both are members of a Fallon parents' organization called Families In Search of Truth, or FIST.
Sands, who has visited Fallon more than 20 times since 2001, lost his daughter Stephanie to leukemia that year, at the age of 21. (Stephanie Sands is included in the official government count in Fallon. Had she lived in Sierra Vista, she would have been excluded, because the Arizona state cancer registry does not count childhood leukemia cases if the child is older than 14 when diagnosed. Dr. Tim Flood, medical director of Arizona's state cancer registry, has explained that above the age of 14, children's behavior changes, and their possible sexual activity, smoking, drug-taking and hobbies--such as working on cars--muddies the data.)
Sands has become an full-time activist and citizen scientist, and has filed a wrongful-death suit against alleged polluters in Fallon.
"It's one way people deal with the helplessness, the impotence you feel when you have a child who's going through this struggle," he explains. "As the parent of a cancer patient, it's all out of your hands. All you can do is provide transportation, and love, and backrubs. And that's not nearly enough."
A technical writer, project manager and consultant by trade, Sands now devotes nearly all of his time and much of his income to fighting what he describes as "the injury and killing of children by corporate interests.
"I freely admit I'm obsessed," Sands says. "I could spend all day telling you what the (Nevada State Health Division) and the CDC did wrong in the Fallon investigation. What it comes down to is that what they did wasn't science. That's all. It was not science."
Warneke also observed the Fallon investigation close-up and has been watching the actions of government officials in Sierra Vista "from a distance." He firmly believes that the CDC never intended to find out anything about the clusters.
"You've got all these answers falling right into your lap," he says. His daughter, Annastacia, now a healthy 11-year-old, got sick in Sierra Vista but was diagnosed in Fallon. "She's a unique link. But nobody in the government is interested in even asking the questions. No one is interested in what Annastacia's case could tell them."
Terry Nordbrock, a Tucson mother of a 6-year-old who has recovered from the disease, is blunt: "My impression is that leukemia just makes people in public health tired."
Nordbrock is a co-founder of FACT, which formed to encourage investigation of the Sierra Vista cluster. Formerly a librarian, she is now working on a master's of public health degree at the UA.
"When I talk to people at school, if I even say the words 'cancer cluster,' I get all this eye-rolling. And as eye-rolling goes, it's pretty savage. The attitude is, 'If you believe in cancer clusters, you don't understand math.' But the fact is that historically, many of the greatest discoveries in medicine have been made by looking hard at local outbreaks of disease."
Government scientists in the United States have a long and depressing history with cancer clusters, though: Between 1961 and 1982, the CDC investigated 108 cancer clusters; not one investigation determined a cause. There are those, even within the CDC, says Nordbrock, who say that failure was inevitable, given the agency's methods. After nearly three decades of failure, in 1990, the CDC recommended that clusters not be investigated, but "managed" in the interests of "good community relations."
The investigation in Fallon, then, was the first of its kind in nearly 15 years, and was undertaken only under intense political pressure: Sens. Harry Reid, D-Nev., and Hillary Clinton, D-N.Y., held a Senate committee hearing on Fallon in 2001. After spending an estimated $1 million, the expert panel's final recommendation was that, while it saw no connection between Fallon's extraordinary levels of contamination with both tungsten and arsenic--the latter is a known carcinogen, although not one that has been linked specifically to leukemia--Fallon's water should be treated to reduce arsenic levels. It also recommended that the biological effects of tungsten be investigated, something that Witten had already begun to do on his own.
That was it.
"In public-health investigations, there is a pattern of reassuring findings that do not lead to change," Nordbrock says. "Cleaning up toxins in the environment costs money for business; treatment of cancer makes money for business. This political climate is simply not friendly to prevention."
Nordbrock is more measured than Warneke. He uses the words "farce" and "cover-up" to describe the government's response to the clusters. (The title of a scathing 1992 study of the federal government's handling of Superfund sites, Inconclusive by Design, often came up in interviews for this article.)
"The (Fallon) investigation was run in a faulty manner," says Warneke.
"First of all, Anna should have been included in the Sierra Vista study, not the Fallon one, because she'd been living in Sierra Vista and had moved to Fallon with her mother just two weeks before she was diagnosed. But no, that didn't fit. She had to be in Fallon. I told them there were all these other cases down in Arizona, maybe they should do some kind of comparison, but they weren't interested in that."
Then the government stalled.
"The CDC kept saying they had to wait for the state health department to invite them, so even though we, and the county, and everybody else had been begging for two years, they didn't get started until our kids were through treatment and their bodies had been chemically altered. If they'd gotten samples before they went into chemo, when we started asking, it might have been different," says Warneke.
Warneke and his fellow FIST parents also have doubts about the environmental sampling.
"They come in and take samples in your house. OK, the first thing you do before you bring a chemo patient home is sterilize everything, so nothing in the house is going to be the way it was before the child went in for treatment. And then, when they came in to collect, they did things like vacuum the carpet for a dust sample in this little area that was all closed off from the rest of the house. Like that was a good sample of what she'd been breathing. They put a radon gas detector in a corner behind a teddy bear, when it said right on the can that it should be out in the middle of a room. We got pictures of them taking soil samples for jet fuel all the way across a field from the Kinder Morgan pipeline--they were nowhere near the pipeline itself. They identified my brother's place as a site where they took water samples. They were never there.
"It was just one thing after another. And then they present these findings like they're so accurate, so exact.
"Look, before they ever started, they kept saying that they wouldn't find anything," says Warneke. "Then at the end, they come tell you, 'See? We didn't find anything.' As far as I can see, it's just repeating down here in Sierra Vista. It's a self-fulfilling prophecy."
Another concern is that the biological samples in Fallon were tested for only one marker of exposure to jet fuel, something the townspeople were worried about--Fallon sits next to the Fallon Naval Air Station, and the locals have reported leaks where the pipeline runs through the town. The marker they did look for was benzene, which passes out of the body in a day or two.
Warneke's group says that flights over the town stopped for some weeks before the CDC's team came to take samples. This also happened last year in Sierra Vista, according to Nordbrock.
"But then the Army started flying again while the collection team was there, so it's hard to know what to make of it," says Nordbrock. "When I called around at the base, they said they'd decided the Army hadn't issued the right sort of permit to itself, and that's why they grounded the jets. Who knows?"
Even more disturbing, say Sands and Warneke, is that the town of Fallon cut down all the trees around three of the town's four elementary schools--the three schools that sit next to Kinder Morgan's pipeline to the base.
"Sheppard and Witten cored those trees before they cut them, fortunately," says Sands. "So it didn't work. By the way, the CDC never went into the schools, where kids, if you think about it, spend more time than anywhere else, except at home. If you were actually trying to find what kids had been in contact with, wouldn't you collect samples there?"
If the state health departments' and the CDC's eagerness to exclude cases and apparent lack of zeal in collecting data weren't enough to arouse the suspicion of worried families, what they do to the data they do collect might be.
All of the CDC's cluster investigations to date use a case-comparison model in which the possible risk factors of families with sick children are compared to those of similar but healthy families living in the same place. The data is then subjected to elaborate statistical analysis designed to eliminate the role of chance. The smaller the sample, the less likely the method is to produce meaningful findings: This is the reason public-health officials give for being so sure such investigations will not yield a causal connection.
Another feature of the method seems to preclude meaningful findings: In comparing well families' exposures to those of families with sick children, the assumption is that higher exposures lead to more illness, and that if a particular level of exposure isn't making everyone sick, it is not a cause of illness. It's obvious, though, that exposures to things that we know cause cancer, such as cigarette smoking, don't cause cancer in everyone: Only one out of 10 smokers gets lung cancer, and many people who are moderate smokers, or who only inhale secondhand smoke, get cancer, while many heavy smokers don't. But neither of those facts means that cigarettes don't give people cancer.
In making comparisons only among people who've been exposed, the critical contrast between people who've been exposed and people who have no exposure seems to get smoothed off. But the statistical methods used by epidemiologists are so hard to understand, no one but epidemiologists are able to critique them. (Sheppard, for instance, who's an expert in a highly technical field, inorganic dendrochemistry, found the CDC's report on Fallon extremely difficult to follow.)
"I think that this is what you get when you reduce a child, a sick child, a child who's facing death, to a number. I think bad science is the inevitable result of that reduction," says Sands.
The Sierra Vista and Fallon clusters have produced a crop of citizen scientists.
Terry Nordbrock monitors every move government agencies make in Sierra Vista, and peppers ADHS and the CDC with memos and letters. When he lived in Fallon, Matt Warneke spent many nighttime hours crawling around Fallon with a night-vision camcorder documenting surreptitious repairs to a pipeline that supposedly never leaked. Both have put their sick kids in front of cameras so that no one can see them as numbers.
Floyd Sands has gone even further. In October 2002, with Witten's encouragement and advice, he and a team of volunteers conducted a door-to-door survey in Fallon in which they interviewed nearly 45 percent of the town's population about cancer of all kinds.
"I had kept coming back to town after Stephanie died--I wanted to thank my friends there for their support, and, I don't know, I was just haunted by the place. And I heard about all this cancer--it seemed like everybody I talked to knew someone who was sick. What finally tore it was that I started hearing about young boys with testicular cancer. Testicular cancer got me moving."
The data from "Stephanie's Walk," as Sands called the survey, is now in the hands of an epidemiologist, who is verifying and analyzing it.
"So far, it looks like it's holding up," he says.
Among the reports given by the 3,379 persons surveyed, Sands and his volunteers found 34 adult brain cancers, 27 of which had resulted in death.
"Fallon doesn't have one cluster. It has a bunch of them," he says. "They're there. They're just not officially acknowledged."
Perhaps even more ominous were the stories of astonishingly fast, aggressive cancers, and multiple cancers attacking the same person.
"We found people going from diagnosis to death in a few days" Sands says. "One old woman had a headache on Sunday afternoon, was diagnosed with a medulla blastoma (a type of brain cancer) on Wednesday, and died that Friday while doctors were deciding how to treat her. We heard about two brothers, roughnecks from Montana. They'd lived in Fallon for years and drilled all around the state. After they went back home, the younger one died of acute Hodgkin's disease in three months. Not long after, the other brother came down with non-Hodgkin's lymphoma, got treated and went into remission. He felt bad for a few months, then one morning woke up feeling terrible and died that day. When they opened him up, they found the lymphoma, plus bone and bladder cancer. Not one cancer that had metastasized to different places--three distinct cancers. We just kept finding this stuff."
Since all this data was collected by laymen, it cuts no ice with the Nevada State Health Division or the CDC. Sands' findings on brain cancer, though, prompted Witten to look at a gene associated with brain cancer in his mouse pups in his latest study, and that research panned out.
"You have to have an observation of what's there, of what exists, to begin with," says Sands. "From that, somebody can form a hypothesis, and then test it, and then start combining the results with other hypotheses. That's how everybody but the government does science."
Sheppard and Witten, both highly qualified researchers, have also taken grief for stepping outside the lines.
"We've presented at some important meetings," says Sheppard, "and we've been well-received. But there have been these moments of, 'Wait, you're a biomedical guy, and you're a tree guy, and you're working together?'"
Witten first contacted Sheppard four years ago to see whether he could get a fix on changes in the air quality in Fallon over time through tree-ring analysis, but both have subsequently stretched the boundaries of their disciplines. They've set up and laboriously serviced air monitors. Sheppard has branched out, as it were, from analyzing tree rings to using lichens as monitors--he and Witten are currently using the plants to try to confirm their air-monitor findings in Sierra Vista and Elk Grove.
"Yeah, so I'm not a lichen guy, either," says Sheppard. "But I know how it works and who to consult."
And Sheppard had to invent a new method of processing tree cores to eliminate the possibility, raised in a peer review, that tungsten in coring tools could contaminate cores and skew findings: He recently perfected a technique that uses lasers to peel of the outer edges of core samples without touching them.
Witten, in the meantime, is writing grants for further mouse studies, but he'll do anything. Both men have been seen sweeping the sidewalks of Fallon for surface-dust samples--yet another type of evidence, and, they hope, another confirmation that they have a genuine piece of the puzzle.
"We've been at this four years, and we're nowhere near done. But we are getting some results," says Witten, sounding tired.
"This is how science goes. You go from A to B to C, and once in a while, you get to jump from D to F. But usually it's back to B again."
In the meantime, Sands, Nordbrock, a mother from Elk Grove and other cluster veterans from around the country have joined with interested doctors and scientists to equip citizens to document disease clusters for themselves.
"My personal motto for what we're doing is, 'No More Fallons,'" says Sands.
The National Disease Cluster Alliance, a nonprofit formed last year, already has many tools for concerned laypeople online, and plans to roll out a Community Toolbox, a set of peer-reviewed protocols for collecting usable data on clusters, this July.
"On one CD, we'll have surveys, questionnaires and advice on dealing with the government, media relations and so on," Sands says. "We take them through everything they need: case definition, identification, verification. And we'll tell them that the first thing they do, on day one, is get an environmental snapshot of their community.
"What we want to do is empower communities, and help them eliminate that two- or three-year escape window the government agencies always leave hanging open for the black cats to escape through. We're going to finally slam that window shut and nail it tight."
He pauses. "We're doing it for the kids."