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Agent Orange exposure linked to nonmelanotic invasive skin cancer
Exposure to 2,3,7,8-tetrachlorodibenzodioxin, a contaminant of Agent Orange, appears to be associated with the development of nonmelanotic invasive skin cancer, study results showed.
The findings showed about half of Vietnam War veterans exposed to the herbicide developed that form of skin cancer.
“Although 2,3,7,8-tetrachlorodibenzodioxin exposure has been linked to many diseases, its influence in the risk of developing skin cancer in humans remains unclear,” the researchers wrote. “Our clinical experience suggests that exposure could influence the risk of developing nonmelanotic invasive skin cancer, perhaps depending on the duration and type of exposure and certain patient characteristics.”
To determine the connection between Agent Orange exposure and increased skin cancer incidence, researchers evaluated 100 consecutive patients who were enrolled in the Agent Orange Exposure Registry at the Veterans Affairs Hospital of Washington, D.C., between August 2009 and January 2010.
Chart review, questionnaires and/or doctor interviews were used to ascertain the following information: Fitzpatrick skin type, eye color, number of years of exposure to 2,3,7,8-tetrachlorodibenzodioxin (TCDD), type of exposure, time since last exposure, number of skin cancers, and time between exposure to Agent Orange and initial diagnosis of nonmelanotic skin cancer (if applicable), systemic cancers or a diagnosis of chloracne.
Because the acquisition of control data from the VA database was not possible for this study, the researchers used normative data on nonmelanotic invasive skin cancer occurrence from the US general population. The mean age of the study population was 65.7 years (range, 56-80).
The types of exposure to TCDD were classified as follows: living or working in contaminated areas (56%), actively spraying it (30%) or traveling in contaminated areas (14%).
Fifty-one percent of patients in the study population were found to have nonmelanotic invasive skin cancer, which was significantly higher than the incidence rates among the national age-matched general population (23.8%; P<.001). Among the study population, 43% had chloracne and 26% had systemic malignancies, such as prostate (14%), colon (3%) or bladder cancer (2%). An inverse relationship was identified between high Fitzpatrick skin type score (P=.01) and dark eye color (P=.036) and occurrence of nonmelanotic skin cancer. Active spraying of TCDD (73% vs. 67%; P=.003) and diagnosis of chloracne (81% vs. 28%, P<.001) were linked to increased rates of nonmelanotic skin cancer.
“TCDD is among the most carcinogenic compounds ever to undergo widespread use in the environment,” study investigator Mark W. Clemens, MD, of the department of plastic surgery at The University of Texas MD Anderson Cancer Center, said in a press release. “Further studies are warranted to determine the relative risk within this patient population, and to determine appropriate management strategies so that veterans may receive the care they earned in service.”
Disclosure: The researchers report no relevant financial disclosures.