Prostate cancer (right) in the tissue section (Image: Otis Brawley / NCI)
Read aloud The Vietnam War has been almost 50 years now - but those involved and those affected are still suffering from the after-effects of this war. In particular, the dioxin-defaced Agent Orange made hundreds of thousands of Vietnamese and US soldiers ill in the following years. Now, a US research team has uncovered another previously unrecognized long-term consequence: veterans exposed to the defoliant have a 75 percent increased risk of developing a particularly aggressive form of prostate cancer. The knowledge of this increased risk could help to detect the aggressive cancer in a timely manner. However, the results also reveal the long-term risks associated with dioxin-containing chemicals, the scientists warn. For this poison still arises as an intermediate product of chemical production chains and waste incineration. Agent Orange was the code name for an end of the 1960s used in the Vietnam War herbicide. This consisted of two chemicals that mimic the plant growth hormone auxin and stimulate the plants to overgrow. As a result, they shed their leaves - and that was exactly the purpose of the operation. Shortly after the war, however, it turned out that Agent Orange was contaminated with dioxin - a highly carcinogenic and mutagenic toxin. As a result, hundreds of thousands of Vietnamese became seriously ill, developed tumors and gave birth to severely malformed children. Cases of lymphoma, leukemia, and other cancers also accumulated among US veterans.

Whether the dioxin contamination also increases the risk for prostate cancer, however, was not clearly established for a long time. This type of cancer typically only occurs in older men. "Now most Vietnam veterans are in their 60s - the age when prostate cancer is most commonly diagnosed, " said Nathan Ansbaugh of Oregon Health and Science University, Portland, and his colleagues. For their study, they now evaluated data from 2, 720 Vietnam veterans who had undergone biopsy for a positive finding at the Portland Veterans Administration Medical Center. They examined whether there was a link between the level of previous exposure to Agent Orange - as evidenced by the medical records - and the frequency and type of prostate cancer.

75 percent higher risk for aggressive tumors

The result: Veterans who were previously exposed to the defoliant were diagnosed with prostate cancer one and a half times as often as unexposed veterans. Even more significant, however, was the difference in the particularly aggressive forms of this cancer: for these, the risk increased by 75 percent, and the deadliest variant was even twice as common as the researchers report. The agent Orange apparently has a specific and strong effect on the aggressive tumors. The only slowly growing and rarely metastasizing cancer variant, on the other hand, receives little support. display

"This is an important difference because the majority of prostate tumors are not fatal and do not require aggressive therapy, " explains lead investigator Mark Garzotto, also from Oregon Health and Science University. However, knowing that the likelihood of an aggressive tumor was increasing among those exposed to Agent Orange or other dioxin-containing chemicals, these patients could be better targeted and monitored for early detection. "Our findings are also a renewed warning of the potential consequences of chemical contaminants in pesticides, " says Garzotto. That does not apply only to wartime.

Nathan Ansbaugh (Oregon Health and Science University, Portland) et al., Cancer, doi: 10.1002 / cncr.27941 © - === Nadja Podbregar


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