The increase in childhood brain tumors and cancers in central east Florida has fortunately begun a more thorough investigation into the elevated brain cancer rates for our area.  This is long overdue. As a physician involved in the treatment and research of chemically induced illnesses and immune system toxicology (the study of how chemicals weaken the immune system), I am watching with interest the direction state investigators choose for research.

I was disturbed by a Stuart, Florida newspaper report of a comment made by one state investigator stating there is "no solid base of information to start from."  To the contrary, there is currently excellent information available regarding suspected causes of related brain cancer, neuroblastoma and blood cancers to help point us in the right direction. First, statistically brain cancer has been increasing over the past 60 years and researchers agree this is not just attributable to improved diagnosis. Each year more than 16,000 children and adults in the U.S. are diagnosed with a brain tumor.  The brain cancer figures below, from the American Cancer Society, show a disturbing trend in the number of cases being found per 100,000 population:

1940.... 1.95 per 100,000 population
1945.... 2.25 per 100,000
1950.... 2.90 per 100,000
1955.... 3.40 per 100,000
1960.... 3.70 per 100,000
1965.... 3.85 per 100,000
1970.... 4.10 per 100,000
1975.... 4.25 per 100,000

These figures showing a steady increase are true for all industrialized countries, and therefore, strongly implicate chemicals used in modern society. The fact that similar increases are occurring in children also point out this is not just an effect among aging Americans.

The next question we need to ask is which chemicals have been linked to brain cancers? Identified risk factors now include workers exposed to chemicals used in vinyl and rubber production, as well as an increased risk for workers employed at oil refineries or chemical manufacturing plants. Exposure to chemicals called nitrosamines, such as in cured meats and baby pacifiers, have also been implicated. Another study by the National Cancer Institute of 3,827 Florida Pest Control Operators found they had approximately twice the normal rate of brain cancer. Dr. Jack Leiss and David Savitz reported in the 1995 American Journal of Public Health of several studies showing pesticide exposure increases risks for childhood cancer. This included one study which found over twice the risk of brain cancer for children exposed to household pesticide extermination. Also reported was research by Dr. Ellen Davis of children with brain cancer under 10 years of age. This study found the children with brain tumors had 6.2 times greater exposure to certain pesticides. A 1987 study by the University of Southern California found children exposed to home and lawn pesticide use had a 6.5 times increased risk of developing leukemia.

Of great concern because of the citrus agriculture in our area are the findings from the Boston University School of Public Health that people living near agriculture growing areas in Cape Cod, Massachusetts were much more likely to develop brain cancer.  Researchers compared the home locations of approximately 1000 cancer patients to the home locations of 1000 patients dying of illnesses not related to cancer. Results showed that living within 2600 feet of an agricultural area resulted in twice the risk for all brain cancers and nearly a 7-fold increased risk for a type of brain cancer known as astrocytoma. (Astrocytomas are in the family of "glioma" cancers which begin in the glial tissue (glial tissue are the cells which hold the other brain cells together). More information on this study can be seen at www.chem-tox.com/cancerchildren.

One of the strongest links of pesticides causing child cancer comes from research of children developing neuroblastoma after their homes were treated with the pesticide chlordane. Researchers at the U.S. Occupational Safety and Health Administration in Washington, D.C. reported of 5 cases of child neuroblastoma which were suspected to have occurred following chlordane treatment in or around the home. In one case, a 3 year 9 month old boy developed neuroblastoma after his family moved into a new home. Two years prior to the child's birth and also when he was two years old, the house was treated for termite infestation with chlordane. This report also discussed other cancers following chlordane treatment, which included 3 cases of aplastic anemia and 3 cases of leukemia. 25 other cases of cancers were reported elsewhere following chlordane home exposure. Many of these cases have moved into litigation.

Another study appearing in the 1981 journal CANCER, detected high levels of chlordane in 13 children with cancer. Researchers have stated that chlordane is a high risk chemical for brain cancer because it is a fat soluble compound and therefore has the potential to accumulate in the brain.

In regards to the so called safety tests conducted by chemical companies on pesticides, there is unfortunately no consideration given to the fact that the developing fetus has been reported to be 50 times more vulnerable to the harm of cancer causing chemicals. Also, the EPA does not take into account that a newborn child does not develop an efficient blood brain barrier until at least one year after birth. The blood brain barrier functions to keep toxic substances out of the brain and is believed to be the reason why epilepsy is shown to be an increased risk factor for developing brain cancer, as epileptic patients have been found to have lower blood brain barrier function.

One reason scientists are still extremely concerned about chlordane is the fact that although its use was stopped in the U.S. in April of 1988, chlordane is such an extremely persistent pesticide that it is still being detected in the air of homes today. In fact, tests of over 1000 homes performed by the U.S. Air Force and other agencies have come to the conclusion that approximately 75% of all homes built before 1988 are contaminated with chlordane and that 6-7% are suspected of being over the maximum safe levels set by the National Academy of Sciences. This is such a large number of homes that toxicologist Dr. Samuel Epstein stated in a major medical journal that, "A national program for monitoring all homes treated is urgently needed to detect persistent contamination." Dr. David Cassidy, a chlordane research toxicologist in Texas, stated that the chlordane contamination problem is of such magnitude nationally that it is, "causing more harm than that caused by cigarette smoking." This is a very strong statement, but one that I certainly agree and brings to reality the magnitude of the problem.

Next we need to look at the research explaining how and why pesticides can be increasing the risk of child cancers. The explanations now show that pesticides are able to cause at least two biological changes in the body that enable cancer to grow. First, pesticides have shown the ability to damage our DNA and genetic structure and the second is that pesticides are now being found to seriously weaken the human immune system. All of us develop cancer cells on a regular basis and it is our immune system which literally attacks and removes these cancer cells from our body.

Regarding children with neuroblastoma, there have been several studies done finding these children frequently have damage to the end of what is called chromosome number 1. Scientists believe this part of the chromosome may be responsible for suppressing tumor growth or controlling cell growth. This genetic damage is not observed in other cells in these children.

Children with neuroblastoma are being found to have defects in the part of their immune system which removes cancer from the body. For instance, it was found by researchers at the University of Hamburg, Germany, that the blood of normal healthy people contains antibodies called IgM which seek out and destroy neuroblastoma cells. However, in a test of 11 people with neuroblastoma, none had properly working IgM antibodies. Other parts of the immune system which have been found to attack neuroblastoma and cancer cells are our cells called natural killer cells and macrophages. In studies of macrophages and cancer, conducted by the Department of Pediatrics, University of Arkansas for Medical Sciences, it was found that exposure to chlordane literally paralyzed the ability of macrophages to search and destroy cancer cells. Certainly, this raises legitimate questions to the role of chlordane and other pesticides in and around homes of children with cancer. It is also of concern, that the two counties showing the highest rates of childhood cancer, St. Lucie and Indian River, are the same two counties with the highest proportion of the area devoted to growing citrus.

Although there are many chemicals a child can be exposed to which can damage his/her chromosome structure, we need to first investigate chemicals the child may have been exposed to on a repeated basis. Therefore, our researchers must look at pesticides which may have been applied inside or around the homes (such as chlordane) as well as pesticides that may have been used in agriculture in the nearby area.

If you have a child with any form of cancer please help us identify the main environmental causes of this illness (many of which are often overlooked) by completing the survey form before you leave our web site by clicking on the link - Child Cancer Survey Form.   Thank you - Wayne Sinclair, M.D.

more information on child cancer can be seen at:

www.chem-tox.com/cancerchildren - medical summaries on environmental causes of child cancer
www.chem-tox.com/neuroblastoma - medical summaries on environmental causes of neuroblastoma