Community Cancer Clusters

munity cancer clusters are viewed quiteCommunity cancer clusters are viewed quite
differently by citizen activists than bydifferently by citizen activists than by
epidemiologists. Environmentalists and concernedepidemiologists. Environmentalists and concerned
local residents, for instance,might immediatelylocal residents, for instance,might immediately
suspect environmental radiation as the culpritsuspect environmental radiation as the culprit
when a high incidence of cancer cases occurswhen a high incidence of cancer cases occurs
near a nuclear facility.near a nuclear facility.
Epidemiologists,in contrast, would be more likely toEpidemiologists,in contrast, would be more likely to
say that the incidences were "inconclusive'or thesay that the incidences were "inconclusive'or the
result of pure chance.And when a breast cancerresult of pure chance.And when a breast cancer
survivor, Lorraine Pace,mapped 20 breast cancersurvivor, Lorraine Pace,mapped 20 breast cancer
cases occurring in her West Islip,Longcases occurring in her West Islip,Long
Island,community, her rudimentary researchIsland,community, her rudimentary research
efforts were guided more by hope — that aefforts were guided more by hope — that a
specific environmental agent could be correlatedspecific environmental agent could be correlated
with the cancers — than by scientific method.with the cancers — than by scientific method.
When epidemiologists study clusters of cancerWhen epidemiologists study clusters of cancer
cases and other noncontiguous conditions such ascases and other noncontiguous conditions such as
birth defects or miscarriage,they take severalbirth defects or miscarriage,they take several
variables into account,such as background rale-variables into account,such as background rale-
(the number of people affected in the general(the number of people affected in the general
population),cluster size, and specificity my notablepopulation),cluster size, and specificity my notable
characteristics of the individual affected in eachcharacteristics of the individual affected in each
case).If n cluster is both large and specific, it iscase).If n cluster is both large and specific, it is
easier for epidemiologists to assign blame.easier for epidemiologists to assign blame.
Not only must each variable be considered on itsNot only must each variable be considered on its
own,but it must also be combined withown,but it must also be combined with
others.Lung cancer is very common in the generalothers.Lung cancer is very common in the general
population. Yet when a huge number of casespopulation. Yet when a huge number of cases
turned up among World War shipbuilders who hadturned up among World War shipbuilders who had
all worked with asbestos, the size of the clusterall worked with asbestos, the size of the cluster
and the fact that the men had had similarand the fact that the men had had similar
occupational asbestos exposures enabledoccupational asbestos exposures enabled
epidemiologists to assign blame to the leprousepidemiologists to assign blame to the leprous
mineral.mineral.
Although several known carcinogens have beenAlthough several known carcinogens have been
discovered through these kinds of occupational ordiscovered through these kinds of occupational or
medical clusters, only one community cancermedical clusters, only one community cancer
cluster has ever been traced to an environmentalcluster has ever been traced to an environmental
cause. I leally officials often discount acause. I leally officials often discount a
community's suspicion of a commoncommunity's suspicion of a common
environmental cause because citizens tend toenvironmental cause because citizens tend to
include cases that were diagnosed before theinclude cases that were diagnosed before the
afflicted individuals moved into the neighborhood.afflicted individuals moved into the neighborhood.
Add to this the problem of cancer's latency. UnlikeAdd to this the problem of cancer's latency. Unlike
an infectious disease such as cholera, which isan infectious disease such as cholera, which is
caused by a recent exposure to food or watercaused by a recent exposure to food or water
contaminated with the cholera bacterium, cancercontaminated with the cholera bacterium, cancer
may have its roots in an exposure that occurredmay have its roots in an exposure that occurred
10 to 20 years earlier.10 to 20 years earlier.
Do all these caveats mean that the hard work ofDo all these caveats mean that the hard work of
Lorraine Pace and other community activists is forLorraine Pace and other community activists is for
nothing? Not necessarily. Together with manynothing? Not necessarily. Together with many
other reports of breast cancer clusters on Longother reports of breast cancer clusters on Long
Island, the West Islip situation highlighted by PaceIsland, the West Islip situation highlighted by Pace
has helped epidemiologists lay the groundwork forhas helped epidemiologists lay the groundwork for
a well-designed scientific study.a well-designed scientific study.