Families Against Cancer & Toxics
Stop cancer before it starts
by Terry Nordbrock, MPH, MLS
September 12, 2009
Mother of a child diagnosed with leukemia
Investigating disease clusters represents some of the best work public health has ever done. One famous example of a successful disease cluster investigation was John Snow's analysis of the 1854 cholera outbreak in London. Snow used maps of cholera patients overlaid with drinking supply maps to prove that contaminated water caused the disease. Snow acheived a successful public health intervention by removing the pump handle to the water source that was contaminated with sewage, and brought the disease outbreak to an end. While considerable controversy followed his findings that drinking water must be kept separate from the sewage system, it ultimately created a public health revolution with sweeping changes to plumbing and sewage treatment. Of all the public health changes ever done, improvements to drinking water quality have saved the most lives.
But it is never easy to study disease clusters, and cancer poses added challenges because of the long latency period. Between 1961 and 1982, the Center for Disease Control (CDC) investigated 108 community cancer clusters in 29 states and five foreign countries. As they did not identify causation in any of these attempts, they decided to discontinue cancer cluster investigations. But cancer continued to cluster, people continued to call for investigations, and the burden fell to local and state health departments. By the late 1980's, the states, deeply frustrated with their experience investigating clusters, called for a national conference to discuss how to best respond to cancer clusters.
This policy was debated and settled on at the National Conference on Clustering of Health Events, February 16-17, 1989, Atlanta GA. Reports from this conference are gathered in a supplemental edition published by the American Journal of Epidemiology in 1990. Many carcinogens have been identified by workplace clusters or as a result of taking a particular drug (such as DES daughters with adenocarcinoma), but only one carcinogen was identified after studying a community-based cancer cluster (erionite, a type of asbestos naturally occurring in the village Karain, in Turkey). Was studying clusters worth all the trouble?
Public health leaders argued all sides of this controversy, but ultimately the people against studying clusters carried the day. Foremost among these was Alan Bender of the Minnesota Department of Public Health: "The reality is that [cluster investigations are] an absolute, total and complete waste of taxpayer dollars," The decisions from that conference led to publication of the CDC's 1990 "Guidelines for Investigating Clusters of Health Events," which is in widespread use by states today. It reads, "the unofficial consensus among workers in public health is that most reports of clusters do not lead to a meaningful outcome." Yet, "report of clusters cannot be ignored. The health agency must develop an approach that maintains community relations and that manages clusters without excessively depleting resources." [emphasis mine]. Some describe this going-through-the-motions approach as "waste, fraud and abuse."
When sixteen children in tiny Fallon, Nevada, were diagnosed with leukemia in five years, CDC undertook a cluster investigation for the first time in two decades. Many theories were raised about exposures that might be involved, including jet fuel, aboveground nuclear testing, EMF activity from Fallon Naval Air Station, heavy metals exposure to arsenic, uranium and tungsten. Nevertheless, after a few years CDC/ATSDR concluded their studies, having found no conclusive cause, but boldly clearing the Fallon Naval Air Station (NAS) of any blame: "After evaluating environmental data and toxicological and medical information, ATSDR concludes there are no past, current or future public health hazards from exposures to NAS-related substances in the environment." .Fallon families criticize the study, pointing to the Memorandum of Understanding that gives the Navy the right to review documents before ATSDR releases them. They are suing to obtain 2000 pages of correspondence between the Navy and the ATSDR, but despite a judge ordering the Navy to comply with their FOIA request, only one page of information has been released to date.
CDC is also involved in the Sierra Vista, AZ childhood leukemia cluster, offering bio-sampling to measure the levels of ~150 chemicals in the bodies of case familes and comparison families.
The childhood leukemia cluster investigations in Woburn, Massachusetts, and Toms River, New Jersey, have been tremendous successes, finding that exposure to TCE in the drinking water was associated with increased
incidence of leukemia. The Toms River study cost $25 million dollars but was worth every penny, because this advance in public health knowledge will directly save lives. Massachusetts has reduced use of TCE by 90%, and safe alternatives are becoming more readily available.
Cancer cluster investigations may be difficult to perform, but the work is essential. It may lead to another revolution improving the quality of our drinking water, food, and air. It may well create a public health intervention as sweeping as John Snow's cholera findings.