New toxins suspected as cancer rate rises in children...
by John H. Cushman, Jr.
The rate of cancer among
American children has been rising for decades. Although the reasons remain
unclear, many experts suspect the increase may be partly the result of growing
exposure to new chemicals in the environment.
That suspicion, while still unproved, is beginning to shape
federal research priorities and environmental strategies.
Depending on which types of cancer are counted, and in what age
groups among the nation’s youth, the rate of increase has amounted to nearly 1
percent a year, according to the National Cancer Institute. Over a few decades, that has meant striking double-digit
Childhood cancer is still far less common than cancer in adults,
and its very rarity makes it especially hard to discern what might be causing
the increase. Its creeping spread has also been masked by better news, as recent
medical gains have made it much more likely that a child with cancer will
But childhood cancer, even when its young victims are cured, can
inflict wrenching costs on children and their families, whether its toll is
measured in financial, emotional or physical terms. Patients can suffer
permanently from brain damage, stunted growth or secondary cancers later in
life, partly as a result of radiation and chemical therapies.
And today, according to experts in the field, a newborn child
faces a risk of about 1 in 600 of contracting cancer by age 10.
In the United States, cancer is diagnosed each year in an
estimated 8,000 children below the age of 15. Cancer, although it kills fewer
children than accidents do, is the most common form of fatal childhood disease,
accounting for about 10 percent of all deaths in childhood.
The increases surprise even people who are predisposed to think
the worst about the ill effects of chemical pollution.
"I had not realized that the numbers were going up that way,"
said Karen Florini, a lawyer specializing in health issues at the Environmental
Defense Fund. "I think it indicates a very disturbing trend that we had better
get to the bottom of."
Acute lymphoblastic leukemia in boys and girls increased 27
percent between 1973 and 1990; since then, the rate in boys has declined, but it
is still rising in girls. Brain cancer, or glioma, increased nearly 40 percent
from 1973 to 1994. These two forms of cancer account for most of the disease in
Other forms of cancer, such as the form of bone cancer called
osteogenic sarcoma and the kidney cancer known as Wilms’ tumor, have also been
rising, although the numbers of cases remain so small that the trends may not be
The increases are big enough that better diagnosis and reporting
of the diseases are unlikely to be the principal explanation, experts say;
childhood cancer is such a serious ailment that it is usually detected.
Although the causes are not known and are probably many, some
experts say, toxins in the air, food, dust, soil and drinking water are prime
So with the Clinton administration putting a high priority on
issues of children’s health and the environment, and with Congress last year
overwhelmingly approving new laws taking children’s exposures into account when
setting standards for pesticide residues in food and contaminants in drinking
water, federal authorities are moving to review the epidemiological data much
more closely and to review environmental regulations that may help fight the
At a meeting in Washington two weeks ago, a team assembled by
the Environmental Protection Agency drafted a research plan that could steer
millions of dollars toward better understanding the problem, beginning next
"The increases are too rapid to reflect genetic changes, and
better diagnostic detection is not a likely explanation," said Dr. Philip
Landrigan, a pediatrician who directs the division of environmental medicine at
the Mount Sinai School of Medicine in New York City and who is the senior
adviser to a new office of children’s health at the EPA "The strong probability
exists that environmental factors are playing a role."
Not all environmental factors involve pollution. Landrigan said
that changes in life style, especially diet, must also be considered and may
play some role. Viruses may be implicated in some cancers, but there is scant
Instead, he and many other experts are inclined to examine the
estimated 75,000 new synthetic chemicals introduced in the last half century,
the emissions from cars, the pesticides in foods and in neighborhoods, the
runoffs in drinking water—the whole collection of chemicals out there, mostly
untested for toxicity to humans, let alone for possible cancerous effects in
If their suspicions prove to be well founded—and that could take
many years to determine—it could usher in a new generation of tighter controls
on pesticides, toxic wastes and other chemicals based on the theory that it may
take less of a carcinogen to afflict a child or a fetus, that their health may
be affected by combinations of chemicals and that their needs ought to come
first in dictating pollution controls.
But first, an expansion of federally supported research is
"I’m talking about new research on air pollutants, water
pollutants and pesticides and their effects on children," said Carol Browner,
the administrator of the EPA, "and new testing guidelines that routinely
incorporate children’s issues into EPA’s risk assessments. I’m talking about
moving beyond the chemical-by-chemical approaches of the past, and instead
looking at a child’s total cumulative risk from all exposures to toxic
She promised to pursue better interdisciplinary and
collaborative studies of suspected environmental causes and mechanisms of
childhood cancer, an initiative that was endorsed at the agency’s conference.
Industry representatives who attended the meeting, though,
cautioned against the government’s moving too fast to react to such sketchy
"It doesn’t appear that anyone really knows yet what the causes
are," said Nancy Doerrer, vice president for scientific and policy programs at
the American Industrial Health Council, which represents a diverse group of
"Yes, there may be some role for environmental causation for
childhood cancer," she said. "But there is also a role for life style, and the
prenatal vitamin supplementation during pregnancy also seems to be very
important in preventing some cancers."
Ms. Doerrer said that the EPA was acting properly by announcing
that it would select a few major regulations for scientific review to determine
whether they adequately protected children.
"But to take too much action without really studying the problem
would be wrong," she said. "You are seeing lots of language being written into
proposed regulations and legislation that is intended to protect susceptible
populations. That seems to be the new buzzword."
The group also recommended developing a National Childhood
Cancer Registry, which would contain information such as exposure histories and
family health data, and for better techniques for screening chemicals suspected
of making children sick.
A cancer registry, which would be a comprehensive database
seeking to include information on practically every child with cancer in the
country, would be "a difficult thing to accomplish," said Dr. Robert Amler,
chief medical officer at the Agency for Toxic Substances and Disease Registry, a
federal agency based in Atlanta.
A first step might be to pool the data that already exist
elsewhere, such as extensive information the agency has collected to track
people exposed to cancer-causing chemicals at Superfund sites.
The childhood cancer registry would improve scientists’ chances
of finding significant associations between exposures to harmful chemicals and
the incidence of cancer, he said.
"Most studies of cancer in children have led to hypotheses, and
in some cases have confirmed or furthered these hypotheses, but almost every
study carries with it very important limitations," he said. "These intrinsic
limitations make it difficult for scientists and policy makers to tell the
public what these studies really mean in terms of real risks to children."
Already, using new legal authority, the EPA is taking the risks
to children into account in setting standards for food and water safety.
The Food Quality Protection Act, which became law last year,
gave the EPA 10 years to review its limits on pesticide residues on food. The
agency is starting with what it thinks are the riskiest chemicals: the
organophosphate, carbameate and organochlorine classes, as well as with other
chemicals that may cause cancer in humans.
But Dr. Lynn Goldman, the assistant administrator for pesticides
and toxic substances, said that although scientists have adequate information to
screen most drugs, food additives and pesticides, they lack even basic toxicity
data for most of the agency’s list of about 3,000 industrial chemicals produced
in the highest volumes each year, many of them found in consumer products and in
"The problem with childhood cancer, of course, is that we really
do not know what causes most of it," she said. "As we are working through
screening the pesticides and tightening up the standards, we would hope that we
are reducing the risks for children, but we really can’t be sure."
Many studies have explored the possible role of environmental
toxins in childhood cancer. Studies have cited possible links between cancer in
children and their exposures to pesticides, their parent’s exposures to
chemicals at work and other factors.
In a study published in The American Journal of Public Health in
February 1995, researchers suggested that "use of home pesticides may be
associated with some types of childhood cancer."
The study examined 252 children in whom cancer was diagnosed in
the Denver area between 1976 and 1983 and 222 control subjects, and it
interviewed their parents about household pesticide use. It found some evidence
that yard treatments might be associated with soft tissue sarcomas, and that
pest strips containing insecticide might be associated with leukemia.
But the researchers conceded that the measures of actual
exposure in studies like this are crude, and called for further research to show
"what exposures, if any, are associated with which particular childhood
Another study, published in The Archives of Environmental
Contamination and Toxicology in 1993, found associations between brain cancer in
Missouri children and the use of pesticides in homes and yards.
But here, too, the researchers conceded weaknesses, including
small sample sizes, potentially inaccurate memories of pesticide use, and a lack
of detailed verification of children’s actual exposures to the pesticides.
Clinicians said that there were many measures already known that
may prevent cancers in children, just as in adults.
"Don’t smoke, don’t expose your kids to cigarette smoke, use
sunscreen, don’t expose kids to radon and asbestos," said Dr. Sophie Balk, a
pediatrician at the Jacobi Medical Center, a public hospital in the
Copyright 1997 The New York