PORTLAND, OR – Exposure to Agent Orange doesn’t increase the risk of all types of prostate cancer among veterans exposed to the chemicals during the Vietnam era, only making more likely that patients will develop the more lethal form of the disease.
That’s according to a new analysis published online in CANCER, a peer-reviewed journal of the American Cancer Society. Study authors suggest that Agent Orange exposure history should be incorporated into prostate screening decisions for veterans.1
“This is an important distinction, as the majority of prostate cancer cases are non-lethal and thus do not necessarily require detection or therapy. Having a means of specifically detecting life-threatening cancer would improve the effectiveness of screening and treatment of prostate cancer,” said lead investigator Mark Garzotto, MD, of the Portland VAMC and Oregon Health & Science University.
The herbicide Agent Orange, heavily used during the Vietnam War, often was contaminated with dioxin, a dangerous toxin and potential carcinogen.
To look for a link between Agent Orange exposure and life-threatening, or high-grade, prostate cancer, Nathan Ansbaugh, MPH, designed and conducted analyses on a group of 2,720 veterans who were referred by multiple providers for initial prostate biopsy. Garzotto compiled biopsy results and clinical information for analysis.
Prostate cancer was diagnosed in 32.9% (896) of the veterans, with 16.9% (459) having high-grade disease. Agent Orange exposure was linked with a 52% increase in overall risk of prostate cancer detection by biopsy and a 75% increase in risk of high-grade prostate cancer. Agent Orange exposure also was associated with more than a twofold increase in the highest-grade, most lethal cancers, according to the authors.
Interestingly, exposure to the herbicide did not confer an increase in risk of low-grade prostate cancer.
Garzotto suggested that study results could be used to improve prostate cancer screening for veterans, allowing for earlier detection and treatment of lethal cases.
“It also should raise awareness about potential harms of chemical contaminants in biologic agents used in warfare and the risks associated with waste handling and other chemical processes that generate dioxin or dioxin-related compounds,” Garzotto pointed out.
1. Ansbaugh, N., Shannon, J., Mori, M., Farris, P. E. and Garzotto, M. (2013), Agent Orange as a risk factor for high-grade prostate cancer. Cancer, 119: 2399–2404. doi: 10.1002/cncr.27941