Agent Orange, dioxin

Agent Orange tied to aggressive prostate cancer risk

Posted on MAY 13, 2013 Written by THANHNIENNEWS LEAVE A COMMENT

Soldiers detect Unexploded Ordnance (UXO) and defoliant Agent Orange during the launch of the “environmental remediation of dioxin contamination” project, in Vietnam’s central Da Nang City

Men who were exposed to Agent Orange chemicals used during the Vietnam War are at higher risk for life-threatening prostate cancer than unexposed veterans, researchers have found.

What’s more, those who served where the herbicide was used were diagnosed with cancer about five years earlier than other men, on average, in the new study.

“This is a very, very strong predictor of lethal cancer,” said urologist Dr. Mark Garzotto, who worked on the study at the Portland Veterans Affairs Medical Center in Oregon.

“If you’re a person who’s otherwise healthy and you’ve been exposed to Agent Orange, that has important implications for whether you should be screened or not screened,” he told Reuters Health.

But one researcher not involved in the new study said it’s hard to take much away from it, given the imprecise way it measured exposure.

Agent Orange – named after the giant orange drums in which the chemicals were stored – was used by the U.S. military to destroy foliage, mainly in southern Vietnam. The herbicide was often contaminated with a type of dioxin, a potently carcinogenic chemical.

The Vietnam Red Cross Society has estimated that up to one million Vietnamese suffered disabilities or health problems as a result of Agent Orange, including children born with birth defects years after their parents were exposed.

Past research has also suggested that U.S. veterans who served where Agent Orange was used are at an increased risk of lymphoma and certain other cancers, including prostate cancer.

For the new study, researchers wanted to see whether exposure was more closely linked to slow-growing prostate cancers or aggressive tumors.

They analyzed medical records belonging to 2,720 veterans who were referred to the Portland VA for a prostate biopsy. About one in 13 of those men had been exposed to Agent Orange during the Vietnam War, according to their VA intake interviews.

One third of all men in the study were diagnosed with prostate cancer, about half of which were high-grade cancers – the more aggressive and fast-growing type.

When the researchers took men’s age, race, weight and family history of cancer into account, they found those with Agent Orange exposure were 52 percent more likely than unexposed men to have any form of prostate cancer.

Separating out different types of tumors showed the herbicide was not linked to an increased risk of slower-growing, low-grade cancer. But it was tied to a 75 percent higher risk of being diagnosed with aggressive prostate cancer, the study team reported Monday in the journal Cancer.

“The increase in the rate of cancers was almost exclusively driven by the potentially lethal cancers,” said Garzotto, also from Oregon Health & Science University.

More research is needed to figure out exactly why that is, he said. In the meantime, Garzotto said veterans who were exposed to Agent Orange should discuss that with their doctors.

But Dr. Arnold Schecter, from the University of Texas School of Public Health’s Environmental and Occupational Health Sciences Program in Dallas, said there’s a “big problem” with just asking veterans if they were exposed to Agent Orange or served in an area where it was sprayed.

“Of those most heavily exposed in the military as best we know, only a relatively small percentage of them had elevated dioxin from Agent Orange in their blood when tested by (the U.S. Centers for Disease Control and Prevention),” he toldReuters Health.

Schecter said that in Vietnam, people who have high levels of that type of dioxin in their blood live in places where the chemical has become integrated into the food supply – or were sprayed directly with Agent Orange.

Another researcher who has studied the effects of Agent Orange agreed that not having blood dioxin levels is a drawback, but said the findings are consistent with past research and general thinking about the chemical.

“Almost all studies have implicated that men with Agent Orange (exposure) either have higher-grade prostate cancer or a more aggressive clinical course,” said Dr. Gregory Merrick, head of Wheeling Hospital’s Schiffler Cancer Center in West Virginia, who also wasn’t involved in the new research.

But, he added, as long as men are getting into the VA system and getting regular evaluations and treatment for cancer, Agent Orange exposure “is not a death sentence by any means.”

Exposure To Agent Orange Linked To Prostate Cancer In Vietnam Veterans

UC Davis Cancer Center physicians today released results of research showing that Vietnam War veterans exposed to Agent Orange have greatly increased risks of prostate cancer and even greater risks of getting the most aggressive form of the disease as compared to those who were not exposed.
The findings, which appear online now and will be published in the September 15 issue of the journal Cancer, are the first to link the herbicide with this form of cancer. The research is also the first to utilize a large population of men in their 60s and the prostate-specific antigen (PSA) test to screen for the disease.
"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."
Chamie also said that, unlike previous studies that were either too small or conducted on men who were too young, patients in the current study were entering their prime years for developing prostate cancer. There was also the added advantage that it was conducted entirely during the era of PSA screening, providing a powerful tool for early diagnosis and tracking of prostate cancer.
More than 13,000 Vietnam veterans enrolled in the VA Northern California Health Care System were stratified into two groups — exposed or not exposed to Agent Orange between 1962 and 1971. Based on medical evaluations conducted between 1998 and 2006, the study revealed that twice as many men exposed to Agent Orange were identified with prostate cancer. In addition, Agent Orange-exposed men were diagnosed two-and-a-half years younger and were nearly four times more likely to present with metastatic disease. Other prostate cancer risk factors — race, body-mass index and smoking — were not statistically different between the two groups.
"Our country's veterans deserve the best possible health care, and this study clearly confirms that Agent Orange exposure during service in Vietnam is associated with a higher risk of prostate cancer later in life," said Ralph deVere White, UC Davis Cancer Center director and a study co-author. "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."
Now a banned chemical, Agent Orange is a combination of two synthetic compounds known to be contaminated with the dioxin tetrachlorodibenzo-para-dioxin (TCDD) during the manufacturing process. Named for the color of the barrel in which it was stored, Agent Orange was one of many broad-leaf defoliants used in Vietnam to destroy dense forests in order to better visualize enemy activity.
It is estimated that more than 20 million gallons of the chemicals, also known as "rainbow herbicides," were sprayed between 1962 and 1971, contaminating both ground cover and ground troops. Most of the rainbow herbicide used during this time was Agent Orange. In 1997, the International Agency for Research on Cancer reclassified TCDD as a group 1 carcinogen, a classification that includes arsenic, asbestos and gamma radiation.
The study was funded by the UC Davis Cancer Center. In addition to Chamie and deVere White, study authors were Bryan Volpp, associate chief of staff, clinical informatics, VA Northern California Health Care System; Dennis Lee and Joon-ha Ok, UC Davis resident physicians with the Department of Urology; and Lars Ellison who, at the time the study was conducted, was an assistant professor with UC Davis and chief of urology with the VA Northern California Health Care System. Ellison is now affiliated with the Penobscot Bay Medical Center in Maine and a major in the U.S. Army Reserve currently serving active duty in Iraq. A copy of the study can be requested by e-mailing Amy Molnar at .com.
Prostate cancer is the second most common malignancy 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.