Because cancer can be scary and there have been a few media reports in Northern Nevada on cancer “clusters”, we thought it would be helpful to many families to hear from Caroline Hastings, MD.

As many of you know, she is one of the Pediatric Hematology/Oncology physicians seeing patients on a regular basis at the Children’s Specialty Center of Nevada-Reno. Dr. Hastings has been treating patients in the Reno area for more than 20 years and knows this community well.  In fact, she was treating some of the patients in Fallon, Nevada between 1997 and 2001 and was also a member of the expert panel created to investigate cancer cases in Fallon.  We also reached out to the state’s medical epidemiologist for his thoughts, which follow those of Dr. Hastings.

 

From Dr. Hastings …

There has been a resurgence of concern regarding new cases of cancer in children in Fallon.  Based on the population of Churchill county and the incidence of childhood leukemia, it is statistically probable that 1 case of childhood cancer be diagnosed every 3-4 years.  A prior cancer cluster occurred in the years 1997-2002, though the last case of cancer in a child residing in Churchill county was in December 2001 (a child who had previously resided in Churchill county was diagnosed elsewhere in July 2002).  An expert panel was convened in February 2001 to investigate this cluster and was composed of experts from the Centers for Disease Control, National Cancer Institute, Children’s Oncology Group, State of Nevada Epidemiology, and the local Pediatric Oncologist treating a majority of these patients (Dr. Hastings).
Two reports were released by the panel, the latest on Feb 23, 2004.

 

http://health.nv.gov/SHO_LeukemiaClusters.htm

 

This panel reviewed current expertise on the causes of childhood cancer, and leukemia in particular, as the above cluster was comprised of only cases of leukemia.  In order to understand how certain environmental exposures may lead to the development of cancer, it is important to identify the carcinogens (known cancer causing agents).  At this time, we do not have this information.  It is known that certain individuals may have a genetic predisposition and exposures to environmental agents (including infection, viruses, potential yet unknown carcinogens or other cancer causing agents, etc.) may then lead to a change or mutation which then causes uncontrolled growth of abnormal cancer cells.

 

The panel could not determine with any certainty why this cluster appeared in Churchill county at this time.  An extensive evaluation of environmental factors (soil, air, water) and measurements in blood and urine of affected children, family and community members did not reveal any significant or alarming findings.  There was concern for a fuel leak in the fuel lines for the Navy base, though this was not found with investigation.  There was concern by some individuals that the levels of tungsten were elevated related to a nearby plant, however there is no evidence tungsten causes cancer, and this is also a naturally occurring element in geologic formations in Nevada and that exposure to this element is not unique to Fallon.  There was also concern due to elevated arsenic levels in the environment, however, again there is no evidence arsenic causes childhood leukemia.  It was determined that arsenic levels in the municipal drinking water were well above those levels considered to be safe, and specific recommendations were made to reduce these levels.  Environmental samples were tested for radon and other radioactive elements and most contaminants measured were not elevated compared with national reference data or existing environmental standards.  (refer to link for Expert panel reports)

 

Of note, there were no cases of childhood cancer diagnosed in Churchill county from December 2001 until this year, over 11 years.  It has been hypothesized that there may have been a viral vector, in which changes induced by a virus in susceptible individuals lead to the cancer predisposition.  Samples from affected children have been studied at UCSF by Dr. Joseph Wiemels to investigate this possibility.

 

http://www.ucsf.edu/news/2007/03/7158/cancer-cluster-tracking-killer-nevada  

 

Dr. Wiemels re-convened the expert panel and many other researchers at UCSF and UC Berkeley and Children’s Hospital & Research Center Oakland.

The expert panel made a number of recommendations for the future:

1.  The state of Nevada should develop a more effective data base (cancer registry) to identify and track cancer diagnosis, so that clusters could be picked up more readily.  This registry is active, however, local treating agencies and physicians have 24 months to report a case.  This of course does not make this a reliable source for tracking cancer clusters in real time.  These recent cases of childhood cancer had not been reported as of November 2012.

2.  The expert panel assumed there would be future cases of childhood cancer and ask that state agencies work together to create a plan to address concerns.  It was recommended that samples from the patients be collected at the time of cancer diagnosis (blood, bone marrow for example) and be stored for potential review by reputable pediatric cancer researchers (such as the Children’s Oncology Group and Dr. Wiemel’s lab in conjunction with the University of California).  It was acknowledged that patients treated on the clinical trials through the Children’s Oncology Group (such as with Dr. Hastings’ group) extra biologic specimens would be available for this investigation.  These recent cases were not referred or treated by physicians/facilities affiliated with the Children’s Oncology Group (national standard) but rather by a local physician at Renown and therefore were not enrolled in these clinical trials (biologic and therapeutic).

3.  The panel made specific recommendations to the state for improvements in the water purification systems and decrease the number of inhabitants relying on private wells for drinking water.  The city of Fallon did respond to this recommendation for construction of a new water treatment plant, increased local education, and availability of bottled water at the schools.

 

More thoughts from Dr Hastings …

At this time it would be inaccurate to state or assume the cluster is back, as has been depicted in recent local media.  It is unfortunate there are individuals who prefer to “stir the pot” for secondary gain rather than assist the community and individuals affected to become knowledgeable regarding past history and current course of action.  These are the facts at this time:

1.  There have been 3 cases of childhood cancer diagnosed in 2012 in Fallon.  There were no cases diagnosed between 2001-2012, so no cases in 11 years.  Statistically, this would mean 3 current cases might be predicted.  Cancer is a rare disease in children, but it continues to occur.  The most common cancers in children are leukemia and brain tumors.

2.  These cases need to be reported to the state cancer registry in real time if not already done.  Families and physicians should be working together and with the state to identify and educate families.

3.  Clusters do not resume 10 years later.  This grouping is not related to the prior cluster.  There is no evidence that any on-going exposures would skip an entire decade of children if in fact there is something in the environment leading to increased risk.

4.  Be respectful of the children and families affected.  They have a lot to endure and local hysteria without solid medical and scientific expertise does not help them.  Their privacy also needs to be respected.

5.  We do not know what causes childhood cancer.  We do know that certain chromosomal abnormalities can increase risk of cancer, but still not predict who will develop it or when.  Unless we know what causes cancer we cannot make assumptions that any exposure to an element or perceived toxin caused the cancer in that child.

6.  There are no tests that can be done on children to determine who will develop cancer or what type.

7.  Experts are available and caution should be taken as to who identifies themselves as experts.  Physicians with appropriate education in childhood cancer research and treatment are the most appropriate experts.  The Children’s Oncology Group has over 200 affiliates in Northern America and the closest local affiliates are at Children’s Hospital & Research Center Oakland and Las Vegas (Sunrise Hospital and University Medical Center; In addition, Jonathan Bernstein, M.D. and Alan Ikeda, M.D. are also members of the Children’s Oncology Group based out of the Children’s Specialty Center of Nevada – Las Vegas.)  Physician members from both of these groups are available to treat children locally at the Children’s Specialty Center of Nevada in Reno.  Dr. Hastings also sees patients in Carson City.

Dr. Hastings was on the Expert Panel and worked closely with the State of Nevada and will continue to do so.  Additionally, Dr. Hastings has been part of the Acute Lymphoblastic Leukemia Strategy Group since 1996 and has worked with other COG pediatric cancer experts across the nation to develop treatment protocols for high risk and relapsed leukemia.

For specific questions or concerns, please contact Dr. Hastings at the Children’s Specialty Center of Nevada-Reno, 775-657-8981 or chastings@mail.cho.org

 

From  Dr. Ihsan Azzam, Nevada State Medical Epidemiologist:

It is really unfortunate that pediatric cancer continues to be part of life; with leukemia being the most frequent pediatric cancer. Additionally, and as you know the incidence rate of pediatric leukemia continues to increase nationally and worldwide.

While numerous national and international renowned scientists and researchers worked and continue to diligently and thoroughly analyze the data collected from our Churchill County Pediatric Leukemia “Cluster” from the 90′s – as of this day nobody knows why that “cluster” started in the first place and how or when it ended.

As Dr. Hastings and other national experts mentioned in the article published at the LVN early in November 2012 – the diagnosis of the two children with different types of pediatric leukemia does not rise to the level of a cluster.

As you probably know we have a very close surveillance system to monitor trends of cancer incidence especially pediatric cancer in Churchill County. Nevada State Cancer Registry data from previous years didn’t show any above expectation rates of pediatric cancer. We continue our close evaluation of newly diagnosed cases and will keep you updated.

Ihsan A. Azzam, MD, PhD, MPH
Nevada State Medical Epidemiologist
4150 Technology Way, Suite 300
Carson City, NV 89706