By Will Dunham
WASHINGTON, April 29 (Reuters) - A chemical that comes from the pesticide DDT may raise a man’s risk of developing testicular cancer, U.S. researchers said on Tuesday.
They found a clear link between testicular cancer and DDE, which is created when the body or the environment breaks down the pesticide DDT.
Men with the highest levels of DDE were 70 percent more likely to have developed testicular cancer than those with the lowest levels, according to the study published in the Journal of the National Cancer Institute.
DDT was banned in the United States in 1972 and other developed countries around the same time. It remains in use in some developing countries to fight malaria.
Massive amounts of DDT were used in farming and other applications, and DDE remains widespread in the environment.
Researchers led by Katherine McGlynn of the U.S. government’s National Cancer Institute examined blood samples provided by 739 men in the U.S. military with testicular cancer and 915 others who did not have it.
The link between DDE and cancer was particularly strong with a type of testicular cancer known as seminoma, which involves the sperm-producing germ cells of the testicles.
The researchers also found a somewhat lower increased risk for testicular cancer in men with higher levels of chemicals related to chlordane, which was used to kill termites and was banned in the United States in 1988.
Testicular cancer often appears in men in their 20s and 30s and is considered among the most curable cancers.
It has been increasing in recent decades in many countries. McGlynn said it is possible DDE could be a factor. She said the findings suggested about 15 percent of the testicular cancer cases in the men in the study could be attributed to DDE.
It is possible some of the men who later developed cancer of the testicles were exposed to DDE at very young ages — in the womb or through breastfeeding, the researchers said.
"In testicular cancer, there’s a fair amount of evidence that something is happening very early in life to increase risk," McGlynn said in a telephone interview.
DDE remains ubiquitous in the environment even decades after DDT was being banned in the United States — and is present in about 90 percent of Americans, McGlynn said.
"The trouble with these chemicals is they hang around a long time. It’s in the food chain now," McGlynn added. People who eat fish from contaminated areas can absorb it, for instance.
Most men with testicular cancer can be cured with surgery, radiation therapy and chemotherapy. The American Cancer Society said about 8,000 new cases will be diagnosed this year in the United States and about 380 men will die of it.
DDT was used during World War II to combat insect-borne diseases such as malaria in military and civilian populations, then gained wide agricultural and commercial usage. (Editing by Maggie Fox and Cynthia Osterman)