Agent Orange Exposure Modestly Increases Bladder Cancer Risk in Vietnam Veterans

Vietnam veterans who were exposed to Agent Orange had a modestly increased risk for bladder cancer, although it did not alter the aggressiveness of the disease, according to recent study findings.

Results from this study, which were published in JAMA Network Open, may lead to more informed discussions between patients and health care providers.

“Agent Orange (exposure was) associated with an increased risk of bladder cancer, and patients should discuss this with their doctors,” study author Dr. Stephen B. Williams, chief of the division of urology at The University of Texas Medical Branch in Galveston, said in an interview with CURE®.

In 2021, the VA added bladder cancer as a potential effect of Agent Orange exposure, which provided opportunities for veterans to apply for benefits.

“If (patients with bladder cancer) were in the Vietnam War (or potentially certain other places where Agent Orange was used or tested), it would be presumed that their bladder cancer was due to their service, and they could apply for benefits that could include compensation and increased health care eligibility in the Veterans Health Administration,” a VA spokesperson told CURE® when the decision was made.

The researchers wrote in the published study that these findings support this VA designation.

“These results support prior investigations and further support bladder cancer to be designated as an Agent Orange-associated disease,” they wrote.

In this current study, researchers analyzed data from 2,517,926 men who were veterans and were at a median age of 60 years when they entered the VA. Of these men, 629,907 (25%) were exposed to Agent Orange and 1,888,019 (75%) were not. There were several areas of interest in this study including the incidence and aggressiveness of bladder cancer.

Men who were exposed to Agent Orange had a significantly increased risk for bladder cancer compared with men who were not exposed. Findings demonstrated that the association between exposure and the risk for bladder cancer was “very slight,” researchers wrote. In particular, exposure to Agent Orange was linked with a 4% increased risk for bladder cancer.

Researchers also sorted patient data by median age at VA entry, which determined that exposure to Agent Orange was not linked with the risk for bladder cancer in men older than the median age of 60 years. Despite this, the analysis found that exposure was associated with a 7% increased risk for bladder cancer in men who were younger than the median age.

“Thus, younger Vietnam veterans exposed to Agent Orange with potentially more life-years to develop bladder cancer were at greatest risk,” the researchers wrote in the published study.

Veterans who were exposed to Agent Orange and were diagnosed with bladder cancer were less likely to have their disease develop into muscle-invasive bladder cancer.

“Although we cannot determine causality given the retrospective nature of our study design, this observation may be due to earlier bladder cancer detection in the group exposed to Agent Orange,” the researchers wrote.

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