In July of 2000 we were informed of concerns among the medical community in Churchill County that the number of recently diagnosed cases of childhood leukemia appeared unusually high. At the time we were first contacted there had been six cases diagnosed over a 5-month period of time. The usual rate of occurrence in a community of this size would be about 1 case every 5 years. Currently we have identified 8 cases of Acute Lymphocytic Leukemia (ALL) that were diagnosed in 2000. Another case had been diagnosed in 1999 and one case of Acute Myelocytic Leukemia (AML) has been diagnosed this year. For investigational purposes we have interviewed an additional 4 case families with recently diagnosed children having ALL and prior residence in Churchill County.
Our initial investigation consisted of face-to-face interviews with each case family. This involved a detailed review of residential history, sources of drinking and cooking water, in-home water treatment, chemical exposures, parental occupations, and medical history. We have also tested the water supplied to each local residence where a case family lives or has previously lived. About 50% of the case family residences were supplied with water from a regulated municipal source. The others obtained water from private domestic wells. We have tested all water, regardless of source, using the battery of analyses required for public water systems under the Safe Drinking Water Act.
Our water analysis to date has not revealed any results that would explain this cluster. There are high levels of naturally occurring arsenic. However, this has been present for throughout the history of the region and has not been specifically linked to the development of childhood leukemia. There are also some areas in which shallow and intermediate depth wells may exceed safe levels of uranium. This is also naturally occurring and is not found at all in the municipal water which comes from a much deeper aquifer. None of our water samples have detected significant levels of volatile or synthetic organic compounds.
After our initial data gathering was complete we convened a panel of national experts from federal agencies and academia. These experts reviewed our processes and data. They also provided and continue to provide advice on further steps that should be taken to continue the investigation. I have included a copy of their initial report with the written copy of this testimony.
Although I am not familiar with the public health resources in New York, I suspect that Nevada has a somewhat leaner infrastructure. We have, therefore, found it essential to utilize advice and resources provided through the Centers for Disease Control and Prevention (CDC) as well as the Agency for Toxic Substances and Disease Registry (ATSDR).
I would like to briefly comment on some obstacles that we have encountered and lessons we are learning. A potentially serious obstacle to our ongoing investigation has come from the legal profession. We are now being challenged to provide copies of our data collection instruments as well as actual data. These demands are coming at a time when we are just beginning to do case-control studies. The danger, aside from obvious concerns about confidentiality, arises when unofficial parallel investigators introduce informational biases into the study population that may blur subtle distinctions between case and comparison families that would otherwise have provided important clues. We have also experienced media sponsored investigations resulting in spurious connections among case families that are over interpreted and result in panic among residents of the community at large. I believe these issues point to a need for lawmakers to provide some form of investigative privilege that would protect the scientific integrity of an ongoing public health inquiry.
Another phenomenon that arises in high profile cluster investigations is the emergence of self-proclaimed experts who promise to find answers more quickly than public health officials. Some of these individuals have legitimate scientific credentials from fields of study that are only tangentially related to the issues under study. Others are completely without scientific training. All of them have a tendency to tell the community what they want to hear, create distrust between the community and public health officials, and cause a waste of resources as health officials investigate and attempt to dispel myths and misinformation.
A lesson we have learned from this is that it is essential to keep the community well informed as to the progress of the investigation. Even seemingly mundane but necessary activities are of interest to the public and help concerned individuals to understand that the investigation is continuing. We conducted a public meeting for the community early on in the investigation, established a toll free hotline that people can call for information, and developed a web page with information specific to the investigation. We have begun to do weekly media briefings and last week conducted the first of what we expect will become a monthly open forum with the community. At our first open forum we had over 150 people in attendance asking questions for more than two hours. Staff to the investigation remained for an additional hour answering one-on-one questions. Involvement of the local medical community in these meetings is essential. One common question that is frequently asked by the public is whether or not they should move away from the area. Unfortunately, we cannot provide them with a science-based answer at this time. We have, however, been able to obtain state emergency funds that have been used to increase staffing by local mental health professionals. This provides a mechanism for individuals to receive assistance in making decisions in the face of scientific uncertainty and to deal with other stressful aspects of living in a community where a significant health concern is constantly the center of attention.
In closing, I would like to mention some things that might be done on a national level that could assist other communities facing a cluster of disease. First, because most children with cancer receive their definitive diagnosis and initial treatment at major cancer centers that may be located in a neighboring state, there can be significant delays in reporting to the central cancer registry in their state of residence. Some form of national cancer registration for childhood cancers would be very helpful in this regard. Secondly, when faced with a cancer cluster, the public attention invariably turns to the environment. There is a seemingly infinite number of possibilities when it comes to evaluating environmental concerns within the context of an emerging or ongoing cluster. A set of national recommendations for environmental surveillance would be helpful in this regard. Third, a standardized national protocol from agencies such as CDC and ATSDR would allow them to respond to state and local concerns more quickly. It has been exceptionally difficult to explain to an impatient public why it should take so long to develop a scientific protocol, have it approved by the appropriate committees for the protection of human subjects, and then implement it in the field. Having some things done in advance would go a long way toward minimizing this frustration in the community.
I hope these remarks have been helpful. I would be pleased to answer any questions the committee may have.
ATTACHMENT Review and Recommendations of Expert Panel: Acute Lymphocytic (Lymphoblastic) Leukemia.