Adapted from the NCI Cancer Bulletin.
Males exposed to a byproduct of the pesticide DDT may have an increased risk of testicular cancer, according to research published online in the Journal of the National Cancer Institute on April 29, 2008. Blood levels of DDE, the main persistent metabolic product of DDT, were higher in a sample of American men with testicular germ cell tumors (TGCT) than in other men. This relatively rare cancer is often treatable, especially when detected early.
The U.S. banned DDT in 1973, but the pesticide continues to be used elsewhere. The chemical and its metabolites are stored in fat tissue and can accumulate, for instance, in humans and in fish. "While levels have declined in the population since the 1970s, DDE remains detectable in the majority of Americans," said lead investigator Dr. Katherine A. McGlynn of the National Cancer Institute's Division of Cancer Epidemiology and Genetics. "This study suggests that chemicals that persist in the environment may have effects years after their usage ceases."
A link between pesticides and testicular cancer was proposed decades ago, but testing the hypothesis has been a challenge because the disease is rare. The researchers studied 739 U.S. servicemen with TGCT and 915 healthy men who had provided blood samples to the Department of Defense, on average, 14 years before the current analysis.
The men in the group with the highest blood levels of DDE were 1.7 times more likely to develop TGCT than men with the lowest concentrations. If the risk estimates are correct, then DDT exposure could account for 15 percent of TGCT cases in the study.
DDT belongs to a family of organochlorine pesticides that may disrupt the body's endocrine system. "Because evidence suggests that TGCT is initiated in very early life, it is possible that exposure to these [pesticides] during fetal life or via breast feeding may increase the risk of TGCT in young men," the researchers write.