Toms River,
N.J., is a
community of
about 90,000
residents and
the site of
an infamous
childhood
cancer cluster.
Push pins
on a map of
Toms River
(opposite
page) mark
the locations
of children
with cancer.
CR | Page No. 36 | Winter 2009
California’s breast cancer registry
to assess if there really are more
cases than you’d expect to see
in this population. The majority
of the time, says Brunner, the
numbers fall within expected
statistical fluctuations. But if
they don’t, then you begin to
probe deeper. For example, is it
an unusual cancer in an unusual
population? The AIDS epidemic,
he notes, was discovered because
doctors saw an unusual cluster of
Kaposi sarcoma, a very rare skin
cancer, in young gay men—and
that rang bells.
Next, he says, you have to look
at plausibility. “If it is a cluster
in men who are left-handed who
live on streets that start with the
letter A, no matter how startling
the number [of cases] is, it’s not
plausible. But if there is a cluster
and a level of suspicion that there
might be a plausible connection,
that is a reason to investigate.”
Ultimately, though, the only way to
know you have a real cluster, and
not simply a statistical anomaly,
is to watch it. “If it is a statistical
fluctuation, it is likely to go away.
If it persists, you are in a whole
different situation.”
FINDING THE CAUSE
It’s easy to assume that if there
is a real cluster, then there should
be an identifiable cause. But
researchers can spend many years
and millions of dollars trying to
find one and still come up empty-handed. Epidemiologist Raymond
Richard Neutra, a physician and
the chief emeritus of the Division
of Environmental and occupational
Disease Control at the California
Department of Public Health,
knows this all too well.
The problem, he notes, is
with cancer itself, a disease that
typically takes decades to develop.
How do investigators identify the
cause of a cancer cluster if the
exposure took place 40 or 50
years earlier? In comparison, “If
we all go to the church picnic and
fall ill with salmonella infection a
day or two later,” he says, “we can
connect the dots and even find the
food that still has the germs in it.”
With cancer, only every now and
then is the “germ” so linkable to
the disease. It happened when an
