Childhood Leukemia, Brain Cancer on the Rise
Experts Say Exposure to Toxic Chemicals May Be Partially Behind the Increase
By Denise Mann
WebMD Health News
Reviewed by Laura J. Martin, MD
toxic chemical bottles

Jan. 26, 2011 -- Childhood leukemia and brain cancer are on the rise, and exposure to chemicals in our environment such as chlorinated solvents and the head lice treatment lindane may be partially to blame, according to experts speaking at a conference call sponsored by Safer Chemicals, Healthy Families.

The group is seeking to overhaul the 1976 Toxic Substances Control Act (TSCA), but not everyone in the scientific community agrees that chemical exposure is connected to the uptick in childhood cancers. Some suggest that improvements in diagnosing childhood cancers may also have a role.

“There are a number of chemical exposures for which the evidence is strong, including leukemia and brain cancer,” said Richard Clapp, DSc, MPH, a professor emeritus of environmental health at Boston University School of Public Health, during the teleconference.

“Unequivocally the rates of these cancers have been going up for the last 20 years or more with about a 1% increase per year,” Clapp says. “It is clear that at least one complement of the cause is environmental chemical exposure. Certainly a portion [of childhood cancers] can be traced back to damage done at the cellular level from chemicals that are carcinogens.”

For example, he says, chlorinated solvents, which are used in many household products like paints, adhesives and spot removers, are strongly associated with childhood leukemia. He cites cancer clusters in Tom’s River, N.J. and Wooster, Mass., where prenatal exposure to these solvents have been linked to leukemia. Such epidemiological studies do not show causation. Instead, they show that this risk factor is associated with a higher risk for developing childhood leukemia.

Clapp also says there is a growing body of evidence linking lindane to childhood brain cancers.
Exposure to Toxic Chemicals

Sean Palfrey, MD, a professor of clinical pediatrics and public health at Boston University, says that chemical exposures can be passed down, much like genes.

“We can eat them or drink them and they can get into our gastrointestinal tracts or we can breathe them in, touch them, and absorb them through skin and they can spread specifically to organs that they are toxic to,” he says. “They may not harm the first organ, but they may harm the blood cells related to leukemia and brain cells related to brain cancer.”

Our bodies have no idea how to detoxify these man-made chemicals or prevent them from being absorbed, he says. “We store them so when a woman gets pregnant, those stored chemicals may be released and circulate into the fetal blood and breast milk. This is a multigenerational problem so if mom is exposed, she can expose the fetus and baby.”

Exposure to any of these chemicals does not mean a person or their offspring will develop cancer. “My grandchildren as well as my children have in their lungs and bodies substances which might be able to cause cancer, but probably won’t because this is a relatively infrequent thing,” he says.

It’s more than the exposure that is linked to cancer risk. “It is timing, genetics, the way it builds up, and where it is stored,” Palfrey says. “All of these things add together to make it harmful.”