Prostate cancer twice as high in Vietnam veterans exposed to Agent Orange

Prostate cancer cells dividing. Image: Steve Gschmeissner/Science Photo Library

The 20 million gallons of dioxin-laden Agent Orange sprayed in Vietnam in the '60s and early '70s to kill foliage continues to hurt U.S. soldiers and Vietnamese citizens.

A study of more than 13,000 Vietnam veterans who served between 1962 and 1971 found that prostate cancer occurs twice as often in those who were exposed to the toxin Agent Orange compared to those who were not exposed to the herbicide. In addition, Agent Orange-exposed veterans were diagnosed two-and-a-half years younger and were nearly four times more likely to develop more aggressive forms of cancer compared with those who were not exposed. Other prostate cancer risk factors such as race, body mass index and smoking were not statistically different between the two groups.

The findings, to be published in the Sept. 15 issue of the journal Cancer, are the first to reliably link the herbicide with prostate cancer through a large population study, according to researchers at the University of California-Davis Cancer Center.  The men in the study, all in their 60s, are enrolled in the VA Northern California Health Care System. They were screened with the prostate-specific antigen (PSA) test used as a tool for early diagnosis and tracking of prostate cancer.

"While others have linked Agent Orange to cancers such as soft-tissue sarcomas, Hodgkin's disease and non-Hodgkin's lymphoma, there is limited evidence so far associating it with prostate cancer," said Karim Chamie, lead author of the study and resident physician with the UC Davis Department of Urology and the VA Northern California Health Care System. "Here we report on the largest study to date of Vietnam War veterans exposed to Agent Orange and the incidence of prostate cancer."

"Just as those with a family history of prostate cancer or who are of African-American heritage are screened more frequently, so too should men with Agent Orange exposure be given priority consideration for all the screening and diagnostic tools we have at our disposal in the hopes of early detection and treatment of this disease," said study co-author Ralph deVere White, UC Davis Cancer Center director in a written statement. (Symptoms of prostate cancer may include problems passing urine, low back pain or painful ejaculation, according to the National Institutes of Health.)

Some cancer physicians were skeptical of the findings and suggested that increased screening for prostate cancer resulted in the higher than normal rates of occurrence. 

Prostate cancer is the second most common form of cancer and the second leading cause of cancer death in American men. It is estimated that there will be about 186,320 new cases of prostate cancer in the United States in 2008 and about 28,660 men will die of the disease this year.

Agent Orange was one of several defoliants containing dioxin tetrachlorodibenzo-para-dioxin (TCDD) used in Vietnam. It is estimated that more than 20 million gallons of the chemicals were sprayed between 1962 and 1971, contaminating not only ground cover but U.S. soldiers and Vietnamese citizens. Thirty years after the U.S. military left Vietnam the country still has 150,000 children with birth defects believed to be a result of their parents’ exposure to Agent Orange.  

Related:

Vietnam Vets need to know: Agent Orange effects can come 30 years or more after exposure; hard-fought for benefits available -- An interview with Jim Fiebke. A dozen diseases, from multiple myeloma to prostate cancer to Type 2 diabetes, have been deemed presumptive for Agent Orange exposure.