Vietnam War veterans exposed to Agent Orange at higher risk for non-melanotic invasive skin cancer
A new report adds to past evidence that risk of non-melanotic invasive skin cancer (NMISC) is increased even four decades after Agent Orange exposure, with at least some exposed veterans having unusually aggressive non-melanoma skin cancers.
Agent Orange is the code name for an herbicide and jungle defoliant developed by the United States military during the Vietnam War. It has been linked to a wide range of cancers and other diseases, caused by the highly toxic dioxin contaminant TCDD.
As of 2009, there were 485,760 Vietnam veterans with documented Agent Orange exposure registered with the U.S. Department of Veterans Affairs, and many of these veterans reported significant health problems,
According to Dr. Mark W. Clemens, M.D, Assistant Professor of Plastic Surgery at The University of Texas MD Anderson Cancer Center,” TCDD is among the most carcinogenic compounds ever to undergo widespread use in the environment”
Dr. Clemens and colleagues set out to determine if prior exposure to TCDD was associated with an increased incidence of nonmelanotic invasive skin cancer.
The researchers reviewed the medical records of 100 consecutive male patients with Fitzpatrick skin types I through IV who enrolled in the Agent Orange registry at the Veterans Affairs Hospital of Washington, D.C., between August of 2009 and January of 2010.
The patients average age was 65.7 years (range, 56 to 80 years). TCDD exposure included living or working in contaminated areas (56 percent), actively spraying it (30 percent), or traveling in contaminated areas (14 percent).
Among the patients 51% had nonmelanotic invasive skin cancer, about twice as high as the rate expected in men of similar age group. The risk of skin cancer increased to 73% for veterans who actively sprayed Agent Orange. Exposed men with the lightest skin types and those with lighter eyes were also at higher risk.
Forty-three percent of the veterans had chloracne, and 26 percent had other malignancies, such as prostate (14 percent), colon (3 percent), or bladder cancer (2 percent).
Exposure by means of active spraying (73 percent versus 67 percent; p = 0.003) and presence of chloracne (81 percent versus 28 percent; p < 0.001) were associated with increased nonmelanotic invasive skin cancer incidence rates.
Exposure to Agent Orange and TCDD has been linked to a wide range of health problems, including many different cancers. However, its association with the basal cell carcinoma and squamous cell carcinoma—the two most common types of skin cancer—has been unclear.
Cases of "aggressive and diffuse" non-melanoma skin cancers in TCDD-exposed veterans were first reported in plastic surgery journals in the mid-1980s. Dr. Clemens and colleagues initiated their study after observing similar patients in their clinic over the last few years. The researchers emphasize that their study has some important limitations—including the lack of detailed information on TCDD exposure and the absence of a comparison group of Vietnam-era veterans not exposed to Agent Orange.
Nevertheless, the results strengthen the previously reported association between TCDD exposure and the development of NMISC, even many years after exposure. Certain groups appear to be at particularly high risk, including veterans actively involved in spraying Agent Orange, those with chloracne, and those with lighter skin types.
Dr. Clemens and coauthors write, “This is the first time one has shown a link between Agent Orange and non-melanotic skin cancers. In addition to associated malignancies, service personnel with previous dioxin exposure need to be counseled on the cutaneous sequelae of dioxin exposure. Length and degree of exposure appear to be associated with the development of carcinomas. Frequent screenings (every six months) are essential for surveillance of these rapidly growing and invasive cancers. Further studies are warranted to determine a relative risk within this large patient population and to determine appropriate management strategies.”
This report appears in in the February issue of Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS).