A core controversy is whether environmental stressors, such as pollution and pesticides, are responsible for the increase of childhood cancers.
II. Childhood Cancer Facts
III. Scientific Model: Struggling to Keep Up with Policy
IV. Costs Are Very High: Who Pays?
V. What Environmental Stressors Cause Childhood Cancers?
VI. Chemicals and Childhood Cancers
The cause of cancer is always a controversial topic. The rate of cancer among U.S. children has been rising since the 1970s. The mortality rate, however, has decreased since the 1980s. There are scientifically established causes of childhood cancer. Family history of cancer, radiation exposure, genetic abnormalities, and some chemicals used to treat cancer are known causes of childhood cancer. The plethora of new chemicals in food, air, water, clothing, carpets, and the soil is strongly suspected as being part of the cause of cancer in children. The scientific model of causality struggles with proof of the cause of childhood cancer and engages fierce environmental controversy in the process. Some aspects of this controversy have moved into the courtroom. There science struggles both with causality by a certain chemical and liability of a specific person (the defendant).
Childhood Cancer Facts
According to the National Cancer Institute (http://www.cancer.gov/cancertopics/types/childhoodcancers), the following set of statistics measures the expanding parameters of childhood cancer.
A newborn child faces a risk of about 1 in 600 of developing cancer by 10 years of age. The rate of increase has amounted to almost 1 percent a year. From 1975 to 1995 the incidence of cancer increased from 130 to 150 cases per million children. During this time mortality due to cancer decreased from 50 to 30 deaths per million children. In the United States, cancer is diagnosed each year in about 8,000 children below age 15. Cancer is the most common form of fatal childhood disease. About 10 percent of all deaths in childhood are from cancer. There are big differences between types of cancer, and researchers investigate these differences because it may lead them to the environmental stressors. Leukemia was the major cancer in children from 1973 to 1996. About one quarter of all childhood cancer cases were leukemia. Brain cancer, or glioma, increased nearly 40 percent from 1973 to 1994. The overall rate of central nervous system tumors increased from about 23 per million in 1973 to 29 per million children in 1996. These two forms of cancer account for most of the disease in children. Lymphomas are the third most diagnosed category of childhood cancer; they are diagnosed in about 16 per cent of cases. There are different kinds of lymphomas; for some categories childhood incidence rates have decreased and for others they have increased. (For example, non-Hodgkin’s lymphomas increased from 8.9 per million children in 1973 to 11 per million in 1996.)
According the U.S. Environmental Protection Agency (EPA), Office of Children’s Health protection, there are substantial differences by age and type of cancer:
Rates are highest among infants, decline until age 9, and then rise again with increasing age. Between 1986 and 1995, children under the age of 5 and those aged 15–19 experienced the highest incident rates of cancer at approximately 200 cases per million children. Children aged 5–9 and 10–14 had lower incidence rates at approximately 110 and 120 cases per million children.
The EPA also reports some ethnic differences in childhood cancer rates:
Between 1992 and 1996, incidence rates of cancer were highest among whites at 160 per million. Hispanics were next highest at 150 per million. Asian and Pacific Islanders had an incidence rate of 140 per million. Black children had a rate of 120 per million, and Native Americans and Alaska Natives had the lowest at 80 per million.
Also, different types of cancer affect children at different ages. According to the EPA:
Neuroblastomas, Wilms’ tumors (tumors of the kidney) and retinoblastoma (tumors in the eyes) usually are found in very young children. Leukemias and nervous system cancers are most common through age 14; lymphomas, carcinomas, and germ cell and other gonadal tumors are more common in those 15–19 years old.
Scientific Model: Struggling to Keep Up with Policy
The last century saw a drastic lowering of infectious disease rates due to strong public health measures and education. In the United States and other industrialized nations, this has been accompanied by a general rise in systemic, whole-body, or immune system breakdowns. Cancer is considered a possible result of a whole-body immune system breakdown. About 100,000 chemicals are released into the environment. Less than 2 percent of them are tested for public health impacts. The tests are done in constrained laboratory conditions, generally considering a given chemical safe if less than one half or one quarter of the mice exposed to it die. The scientific model requires the isolation of an extraneous possible cause or intervening variables. It ignores cumulative, synergistic, and antagonistic real-world chemical interactions that are the exposure vectors of chemicals for children. The actual biological vulnerability of the affected humans is not taken into account. A developing fetus is much more vulnerable to harm by cancer-causing chemicals. It takes a newborn child at least a year to develop an efficient blood-brain barrier, which works to protect the brain while the central nervous system develops. Before this barrier begins to function fully, the infant could be exposed to whatever the mother is exposed to. There is research indicating that children of people who work with dangerous chemicals have an increased frequency of childhood cancer. The problem of childhood cancer is a driving force behind many other environmental controversies. The real-world number of cancer cases in industrialized nations has increased overall, although it depends on demographics and type of cancer.
Environmental scientists, from government, industry, and environmental groups, have been laboring for many years to unravel some of the exposure vectors to children with cancer and sometimes to endocrine disruption. Many chemicals are much more dangerous when mixed with other chemicals. Children are especially vulnerable to many of the chemicals used around the house, such as cleaners and pesticides. Research has found over twice the risk of brain cancer for children exposed to household insecticide. Some studies have found even higher rates of risk. These early studies focus on just one type of cancer from a few known exposure vectors. The cumulative and synergistic emissions of the past are becoming the cancer risks of the present.
Costs Are Very High: Who Pays?
Health care in the United States is another controversy altogether. Access is difficult, and cancer treatments are very expensive. The annual overall incidence of cancer is 133.3 per million for children under 15 years old in the United States. There were 57.9 million children under 15 years of age in the United States in 1997. About 7,722 cases of childhood cancer are anticipated each year, which is very close to the 8,000 reported. Experts have estimated the cancer-related costs for children to be about $4.8 billion. There are other costs. Psychological stress, transportation, time with medical staff and insurers, and time as a health care provider are all also costs.
The cost of treatment of childhood cancer is controversial in that it is generally too much for an average family to afford. This plays into other controversies about the health care system. If the family cannot afford it or if the insurance company requires it, they file a lawsuit against the most likely cause of the cancer. The litigation hurdles of proof and the burden of proof are often insurmountable obstacles.
What Environmental Stressors Cause Childhood Cancers?
The following brain cancer figures, from the American Cancer Society, show a disturbing trend in the number of cases being found:
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 show a steady increase for all industrialized nations. To many public policy makers the cancer rates in these countries implicate chemicals used there. Similar increases are occurring in children. Many chemical manufacturing industries would contest this association, stating that in most cases the scientific evidence neither proves nor disproves causality.
Chemicals and Childhood Cancers
As discussed previously, a major form of childhood cancer is brain cancer. Which chemicals have been linked to brain cancers? Chemical workers are often the most exposed to a particular chemical. They make it, store it, and transport it. Sometimes they also use it. Epidemiologists follow the exposure vector to workers of various suspected chemicals. Brain cancer risks follow workers exposed to chemicals used in vinyl and rubber production, oil refineries, and chemical manufacturing plants. 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. Pesticide exposure increases risks for childhood cancer. Because adult workers had higher rates of brain cancer when exposed to these chemicals in their occupations, researchers surmise that because children are more vulnerable, they may get more brain cancer when exposed to these chemicals.
Some chemicals used in pesticides concern public health officials more than others. Chlordane is one of high concern. Research on children who developed brain cancer after their homes were treated with pesticides led officials to this chemical. The debate over this chemical has moved to litigation in many cases. Chlordane is a high-risk chemical for brain cancer. It is a fat-soluble compound, and such compounds are absorbed into the nervous system, which develops rapidly in children from birth to age 5.
Legal chlordane use was stopped in the United States in April 1988. However, the law was and is poorly enforced. One reason it was made illegal was its long-term killing power, which also made it an effective pesticide. The degree to which a chemical persists in the environment is one measure of how dangerous it could be to the environment and to humans. Chlordane is such a persistent chemical that it is still being detected today. Tests of more than 1,000 homes performed by federal agencies found that approximately 75 percent of all homes built before 1988 show air contamination with chlordane. They also found that 6 to 7 percent of such homes are suspected of being over the maximum safe levels for chlordane exposure in residential housing set by the National Academy of Sciences, a limit that some have argued is too low.
Research into this controversial area has increased. Authors Julia Green Brady, Ann Aschengrau, Wendy McKelvey, Ruthann A. Rudel, Christopher H. Schwartz, and Theresa Kennedy from the Boston University School of Public Health in Massachusetts published “Family Pesticide Use Suspected of Causing Child Cancers, I” (1993). In this peer-reviewed article the relationship between family pesticide use and childhood brain cancer was closely examined. The researchers compared brain cancer rates for families using pesticides and those not using pesticides. They concluded that the chemicals did increase the risk of cancer. Significant positive associations with brain cancer rates were observed in families using regular household supplies and pest-control chemicals. Bug sprays for different kinds of insects, pesticide bombs, hanging no-pest strips, some shampoos, fl ea collars on dogs and cats, diazinon in the garden or orchard, and herbicides to control weeds in the yard were all found by the authors to be part of the chemical vector increasing the risk of brain cancer. These results are still being disputed. Some argue that the sample sizes are very small in some of these studies and the results may not be typical. Unanswered questions fueling the uncertainty that underlies this controversy concern the total range of effects of chemicals. What happens when they combine in water or sunlight over time? Are there possible generation-skipping effects? What happens to the typical child when exposed to these chemicals in their normal environment? What constitutes their regular environment? Does air pollution pose another cancer-causing vector for children? The evidence is fairly conclusive now that secondary tobacco smoke can cause health risks. Originally, tobacco smoking and chewing were considered good for your health. The danger they posed was a conclusion resisted tenaciously by the tobacco industry. Secondary smoke was highly controversial and remains contested when local land-use ordinances restricting the use of tobacco products come into play.
Childhood cancer is a traumatic event for all involved. The costs are very high. Right now it is difficult to overcome scientifically based burdens of proof in litigation. Families with children with cancer often seek legislative recourse to the incidents they believe caused the cancer. Children, as growing beings, naturally absorb more from the environment than adults. The increase in most childhood cancer rates is a cause for alarm for environmentalists and public health officials. Industry tries to cap environmental liabilities through legislation and internal agency advocacy. This all means that this controversy will intensify as more chemicals are linked with childhood cancers.
Robert William Collin
- Brady, Julia Green, Ann Aschengrau, Wendy McKelvey, Ruthann A. Rudel, Christopher H. Schwartz, and Theresa Kennedy, “Family Pesticide Use Suspected of Causing Child Cancers, I.” Archives of Environmental Contamination Toxicology 24, no. 1 (1993): 87–92.
- Davis, Devra Lee, The Secret History of the War on Cancer. New York: Basic Books, 2007.
- Hayman, Laura L., ed., Chronic Illness in Children: An Evidence-Based Approach. New York: Springer, 2002.
- Steingraber, Sandra, Living Downstream: A Scientist’s Personal Investigation of Cancer and the Environment. New York: Vintage Books, 1998.