Agent Orange Linked to Blood Cancer MDS in Vietnam Veterans – Study Finds

A Decades-Old Exposure, Newly Understood: Agent Orange and MDS

For years, hematologist-oncologist Mikkael Sekeres noticed a troubling pattern in his clinic: Vietnam veterans developing myelodysplastic syndromes (MDS), a group of blood cancers. Many of these men had been exposed to Agent Orange, the herbicide blend used by the U.S. Military during the Vietnam War. While Agent Orange has long been linked to several cancers, a clear connection to MDS remained elusive – until now. New research, published this month in Blood Advances, provides compelling evidence linking Agent Orange exposure to the development of MDS, and suggests the disease may present more aggressively in those exposed.

MDS develops when the bone marrow doesn’t produce enough healthy blood cells. Symptoms can include fatigue, frequent infections, and a greater risk of bleeding. It’s often a gradual-progressing disease, typically diagnosed in people in their 70s. But Dr. Sekeres, chief of hematology at Sylvester Comprehensive Cancer Center at the University of Miami, observed veterans developing MDS much earlier, often in their 2010s and 2020s, after exposure in the 1960s and 70s. This raised a critical question: was this a coincidence, or was there a direct link?

Unpacking the Agent Orange Connection

Agent Orange wasn’t a single herbicide, but a mixture. Crucially, its production process resulted in contamination with dioxin, a highly toxic chemical known to disrupt cellular processes and linked to birth defects and various cancers. American soldiers sprayed Agent Orange over vast areas of Vietnam and neighboring countries, sometimes mixing it with kerosene or fuel – both carcinogens – to improve dispersal. The Department of Veterans Affairs (VA) already recognizes several cancers as being presumptively linked to Agent Orange exposure, granting affected veterans access to benefits. Though, MDS was not among them.

“I’ve been describing this as my passion project,” Dr. Sekeres explained. “These mostly young guys were exposed in the ’60s and ’70s, then developed MDS in the 2010s, 2020s. I had a number of vets who were exposed to Agent Orange.” The challenge was proving a causal link, and securing recognition for these veterans.

The MDS Natural History Study: A Decade of Data

The breakthrough came through the MDS Natural History Study, a prospective national registry tracking the development of MDS from diagnosis. Over nearly a decade, researchers enrolled patients from 160 sites across the country, collecting detailed information, including a questionnaire about Agent Orange exposure. The study included approximately half of participants with MDS or a precursor condition, and half without.

The findings were significant. Six percent of those enrolled had been exposed to Agent Orange. Among those exposed, 54% were eventually diagnosed with MDS or a precursor condition, compared to 37% of those not exposed. Importantly, the study similarly revealed that Agent Orange exposure was associated with more complex MDS cases, falling into poor or remarkably poor genetic risk groups. This suggests not only a higher risk of developing MDS, but also a more aggressive form of the disease.

“We actually showed that folks who had Agent Orange exposure were more likely to have progression of their MDS,” Dr. Sekeres stated. The researchers theorize that exposure at a younger age initiates a “grim rose path towards cancer,” where initial genetic mutations accumulate over time, leading to earlier and more severe disease.

Disparities in Exposure and Impact

The study also highlighted a concerning disparity: Black veterans were three times more likely to report Agent Orange exposure than their white counterparts. Researchers suggest this may be due to the fact that Black soldiers were often assigned to frontline positions during the Vietnam War, increasing their risk of exposure. This finding underscores the importance of considering social determinants of health and equity in research and healthcare access.

Beyond Vietnam: A Wider Implications

The implications of this research extend beyond American veterans. Anyone exposed to Agent Orange, including the civilian population of Vietnam and neighboring countries, may be at risk of developing MDS. The study identified distinct genetic changes in MDS samples from those exposed to Agent Orange, strengthening the evidence for a causal relationship. Dr. Sekeres emphasized that early detection is crucial for anyone with potential exposure and developing blood abnormalities.

“If I were Vietnamese and exposed and started to develop a blood count that’s abnormal, I would be quick to seek medical care and witness if it can be diagnosed at an earlier stage. Treatment is more effective, and you can help people enjoy a better quality of life,” he said.

What’s Next for Veterans and Research

Dr. Sekeres’s primary hope is that this research will prompt the Department of Veterans Affairs to recognize MDS as a presumptively linked condition to Agent Orange exposure. Currently, veterans must provide extensive medical evidence to prove a direct service connection, a challenging and often frustrating process. Recognition by the VA would automatically qualify affected veterans for disability compensation and healthcare benefits.

The research team is continuing to investigate the specific genetic mechanisms by which Agent Orange exposure leads to MDS. Further studies are needed to understand the long-term effects of exposure and to develop more effective prevention and treatment strategies. The findings also highlight the importance of ongoing surveillance for MDS in populations with known Agent Orange exposure. Stars and Stripes reports that this study is a significant step towards acknowledging the full scope of Agent Orange’s legacy.

For Dr. Sekeres, the culmination of eight years of research is deeply personal. “It’s an enormous sense of pride,” he said. “I feel like I’m doing something for my country, particularly for the veterans who were serving. We feel like we’re doing the right thing and giving back to these folks.”