Study Links Pesticide, CancerDec 1, 2004 | Newsday
There is an apparent link between a commonly used agricultural pesticide and lung cancer, and caution should be exercised when using the product, government scientists say in a study released today.
Scientists from the National Cancer Institute studied the organophosphate sold as chlorpyrifos, contained in 800 products all of them pesticides. It is one of several toxic compounds the institute is studying for potential to cause cancer and other serious disorders.
"In this study we looked at cancer risk among farmers in two states, and we actually looked at all cancers," said Dr. Aaron Blair, a cancer epidemiologist in the cancer institute's occupational and environmental epidemiology branch. But lung cancer appeared to be the more prevalent malignancy in people who routinely used the compound over many years.
Chlorpyrifos, defined as a broad-spectrum pesticide by the Environmental Protection Agency, was widely used by nonfarming households as a pesticide until 2000, when the agency required that only people licensed to use the chemical would be allowed to purchase it.
Blair said the new study, which involved 60,000 men and 5,000 women in two states who registered to use the compound for farming, is the first human evidence that the pesticide can cause cancer. Previous studies that linked the pesticide to disease were conducted in laboratory animals. The new study suggests the chemical can damage DNA in the lungs.
The link to lung cancer was dose-dependent, and those with the greatest exposure over the longest periods of time were more likely to develop the disease. Researchers studied farmers because they are more likely to have high-dose exposures.
The report in today's issue of the Journal of the National Cancer Institute showed that farmers in Iowa and North Carolina who regularly used the compound were more likely to develop lung cancer than those who chose other types of pesticides.
Blair said chlorpyrifos for years has been aimed at a family of insects that attack corn.
A new round of studies involving the compound and a larger group of women is aimed at determining whether it plays a role in the development of breast cancer.