Increasing evidence is emerging that exposure to Agent Orange, a herbicide and defoliant used during the Vietnam War, increases risk for a variety of health problems, including prostate cancer, although the exact mechanism is unclear. Dioxin, its known carcinogen, also is found in herbicides and pesticides used by U.S. farmers, forestry and chemical plant workers who studies have shown to have an increased cancer risk. Scientists suspect dioxin activates regulatory regions of genes to enable the uncontrolled cell division that is a cancer hallmark.
Dr. Terris led a separate study of 1,653 veterans at VA medical centers in five cities between 1990 and 2006 that also showed recurrence rates were higher and recurring cancers were more aggressive with Agent Orange exposure. Dr. Sagar R. Shah, MCG urology resident, presented the findings at the 2007 annual meeting of the American Urological Association.
This new study which includes the VA Medical Center in Augusta, Veterans Affairs Greater Los Angeles Healthcare System, Veterans Affairs Palo Alto Healthcare System and six affiliated medical schools included new patients as well as longer follow up on many of the original study patients. As with the previous study, prostate cancer seemed to have a similar course in blacks and whites, but Agent Orange exposure was more common in blacks, who were more likely to be ground troops in Vietnam.
Plenty of questions remain, such as what happens to patients whose primary treatment is standard radiation or brachytherapy, where rice-size radiation pellets are implanted in the prostate, rather than surgery, Dr. Terris says.
She also wants to know whether the veterans' degree of exposure is related to the severity of their cancer. Everyone has some dioxin exposure
|Contact: Toni Baker|
Medical College of Georgia