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Cancer in Children 

Approximately 8,000 children under the age of 15 are diagnosed with cancer each year in the United States.¹ In 1992, cancer was the fourth leading cause of death for American children under age 15, exceeded only by deaths from accidents, congenital anomalies (birth defects), and diseases of infancy.^2,3 The most prevalent forms of the disease in children are leukemia and brain cancer.⁴

The death rate from childhood cancer in the United States has declined dramatically in recent years due to improved treatment.⁵ However, the overall incidence rate of new cancers in children has increased. The trends in some cancer types suggest the need for a closer examination of the underlying factors leading to disease in children. This includes determination as to whether environmental contaminants play a role in causing the disease.

Cancer is characterized by the uncontrolled growth of cells. When a cell becomes cancerous, it loses its ability to regulate its own growth, control cell division, and interpret messages from other cells. Each tumor is believed to originate from a single cell gone awry. The transformation of a normal cell into a cancerous one requires a series of alterations often involving mutations in DNA, the genetic code. The stepwise series of changes usually takes many years to complete, although in young children, the sequence may be accelerated. In addition to possibly causing childhood cancer, exposure to a carcinogen as a child may lead to cancer as an adult. Carcinogens are substances that trigger or accelerate the development of cancer. Cancer may be initiated or accelerated by radiation and by some toxic chemicals.

Possible Environmental Factors

Exposure to certain carcinogens in the environment may be associated with some human cancers.^6,7 People can be exposed to carcinogens through many routes, including air, water, food, drugs, surface contact, and tobacco use. Examples of environmental factors that may be associated with cancer are ^4,7,8:

1. Environmental Tobacco Smoke (or secondhand smoke)
2. Radon
3. Asbestos
4. Ultraviolet Light
5. Some Hazardous Waste
6. Some Pesticides

Environmental Tobacco Smoke

Infants and children who live in households with smokers involuntarily inhale the toxic substances in tobacco smoke. Environmental tobacco smoke (ETS) is a complex mixture of more than 4,000 chemicals, such as nicotine, tars, formaldehyde, and hydrogen cyanide.⁹ Some of these contaminants are known human carcinogens.¹⁰

Radon

Radon, a known human carcinogen, is a naturally occurring, radioactive gas that is colorless, odorless, and tasteless. It comes from the natural decay of uranium, a radioactive metal found in soil and rock in the earth's crust all over the United States. Radon travels through soil and enters the indoor environments of buildings through cracks and other openings in the foundation. Eventually, radon decays into radioactive particles that can be inhaled and then trapped in the lungs. As these particles decay, they release small bursts of radiation that can damage lung tissue and lead to lung cancer later in life.¹¹

EPA estimates that radon may cause from 7,000 to 30,000 lung cancer deaths in the United States each year. Radon is the second leading cause of lung cancer deaths in adults, after smoking. An individual's risk of getting lung cancer from radon depends mainly on three factors: the level of radon, duration of exposure, and smoking habits. Risk increases in individuals exposed to high levels of radon over a long time. The risk of dying from lung cancer caused by radon is much greater for smokers than for non-smokers.

Asbestos

Asbestos is a fibrous mineral that was used widely in construction materials, such as shingles for roofing and siding, pipe and boiler insulation, floor tiles, ceiling panels, coatings, and gaskets. It is present in schools and other public buildings as well as in some residential structures. Asbestos has caused lung cancer and malignant mesothelioma in the children of asbestos workers. The children were exposed to asbestos-contaminated dust brought home from work on their parents' shoes and clothing. EPA estimates that at least 1,000 premature deaths from cancer will occur in this country over the next 30 years among children who are exposed today to asbestos in schools.¹² Asbestos is harmful only when inhaled. If an asbestos-containing product, such as a floor covering, is not disturbed enough to release microscopic particles into the air, no disease is expected to result.

Ultraviolet Light

Overexposure to the sun's harmful ultraviolet (UV) light may damage children's skin. Ultraviolet light is radiation from the sun that has a wavelength shorter than visible light (toward the violet end of the visible spectrum) but longer than that of X-rays. This type of radiation has increased on the earth's surface due to damage to the earth's ozone layer in the outer atmosphere. Excessive sunburns experienced by children 10-15 years of age increase by three fold the chance of developing malignant melanoma, the most deadly kind of skin cancer, later in life.^13,14

Hazardous Waste

Exposure to hazardous wastes that have been released into the environment may present serious health hazards to children. Hazardous wastes include substances that have cancer or non-cancer health effects, are corrosive, or may present a danger due to fire or explosion. They include a wide range of organic chemicals and heavy metals, as well as strong acids and bases. Children may be exposed to such wastes when they play or live near uncontrolled hazardous waste sites or spills. EPA estimates that 12 million people, including 4 million children, live within one mile of one of the nation's hazardous waste sites. Many more children suffer from the toxic effects of heavy metals, such as lead, or are poisoned accidentally from improper pesticide use in their homes.^15,16

References

1. Miller, B.A., L.A.G. Ries, F.R. Hankey, F.L. Kosary, A. Harras, S.S. Devesa, and B.K. Edwards (editors). 1993. SEER Cancer Statistics Review: 1973-1990. NIH Publication Number 93-2789. National Cancer Institute, Bethesda, MD.


2. USPHS. 1991. Vital Statistics of the United States, 1988, Volume II: Mortality. National Center for Health Statistics, U.S. Public Health Service, Washington, DC.


3. Parker, S.L., T. Tong, S. Bolden, and P.A. Wingo. 1996. CA-A Cancer Journal for Clinicians. Volume 46, Pages 5-28.


4. Zahm, S.H. and S.S. Devesa. 1995. Childhood Cancer: Overview of Incidence Trends and Environmental Carcinogens. Environmental Health Perspectives. Volume 103 (Supplement 6), Pages 177-184.


5. Bleyer, W.A. 1993. What Can be Learned about Childhood Cancer from Cancer Statistics Review 1973-1988. Cancer (supplement). Volume 71, Pages 3229-3236.


6. Doll, R. 1976. The Contribution of Epidemiology to Knowledge of Cancer. Review of Epidemiology and Public Health (FR). Volume 24, Pages 107-121.


7. Weinstein, I.B. 1988. The Origins of Human Cancer: Molecular Mechanism of Carcinogenesis and Their Treatment. Cancer Research. Volume 48, Pages 4135-4143.


8. NRC. 1993. Pesticides in the Diets of Infants and Children. National Research Council. Washington, DC: National Academy Press.


9. USEPA. 1994. Indoor Air Pollution: An Introduction for Health Professionals. GPO Number 1994-523-217/81322. American Lung Association, U.S. Environmental Protection Agency, Consumer Product Safety Commission, and American Medical Association.


10. NIOSH. 1991. Current Intelligence Bulletin 54: Environmental Tobacco Smoke in the Workplace. National Institute for Occupational Safety and Health.


11. USEPA. 1996. Radon: Risks and Realities. U.S. Environmental Protection Agency, Office of Radiation and Indoor Air. August 13.


12. USEPA. 1980. Proposed Rule on Friable Asbestos Containing Materials in School Buildings: Health Effects and Magnitude of Exposure (Support Document). Publication Number EPA 560-12-80-003. U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances.


13. ACS. 1996. Skin Cancer Fact Sheet. American Cancer Society.


14. AAD. 1997. Melanoma Risk Factors Fact Sheet. American Academy of Dermatology.


15. ATSDR. 1996. 1996 ATSDR Report to Congress: 1993-1995. U.S. Department of Health and Human Services, Public Health Services, Agency for Toxic Substances and Disease Registry.


16. USEPA. 1996. Pesticides and Child Safety. Publication Number EPA 735-F-93-050R. U.S. Environmental Protection Agency, Office of Pesticide Programs.

Information provided by the US Environmental Protection Agency

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