Veterans With Agent Orange Exposure Have Elevated Risk of SCLC

A recent study highlights the “elevated risk” of small cell lung cancer (SCLC) associated with Agent Orange exposure in veterans.

Grace Faith Umbalin Salacup, MD, of the University of Maryland Medical Center, and colleagues conducted the study and presented their findings during the American Thoracic Society 2024 International Conference. It was important to gain a better understanding of specific risk factors in veterans, because “beyond the conventional risk factors of age and cigarette smoking for lung cancer, veterans’ distinct military and environmental exposures during and post-service may constitute additional risk factors,” the presenters explained.

Dr. Salacup and colleagues evaluated how exposures to asbestos, radiation, Agent Orange, and noxious inhalants relate to lung cancer and other respiratory pathologies in veterans to address the knowledge gap on the topic.

“Exposures such as asbestos, radiation, Agent Orange, and noxious inhalants are not currently addressed in prevailing risk models,” Dr. Salacup and colleagues explained. “This gap in research emphasizes the importance of investigating how these exposures relate to lung cancer and other respiratory pathologies, including respiratory bronchiolitis.”

The retrospective, single-center, cohort study included 293 veterans who were seen at a lung mass clinic between 2015 and 2022. The mean age was 69 years, nearly all (96.3%) were male, and 44.7% were Black. Nearly all (97.6%) had a history of smoking, with 91.5% having a pack-year history of 20 or more.

Asbestos exposure, occurring in 58.02% of veterans, was the most commonly reported exposure in the cohort, followed by Agent Orange (37.90%), radiation (35.15%), oil fumes (8.87%), and burn pits (3.75%). More than half (55.63%) of the cohort had adenocarcinoma, followed by squamous cell (26.28%), small cell (9.56%), metastatic cancer (1.71%), and large cell carcinoma (0.68%). However, 6.14% of the cohort did not have a histologic diagnosis.

The study showed that veterans with >20 pack-year tobacco use had a higher risk of developing adenocarcinoma (risk ratio [RR], 9.94; 95% CI, 1.3-75; P=.027). Veterans with exposure to Agent Orange had an elevated risk of developing SCLC (RR, 4.04; 95% CI, 0.993-16.3; P=.049). Veterans who had exposure to burn pits showed increased odds of being diagnosed with respiratory bronchiolitis (odds ratio, 5.5; 95% CI, 0.96-32; P=.055), but the study authors reported that this association did not reach statistical significance.

The study, which described “pertinent military and environmental exposures encountered by the veterans” seen in the lung mass clinic, showed that the “majority had significant asbestos exposure, followed by Agent Orange.” The study “highlights elevated risk of [SCLC] linked to Agent Orange exposure,” Dr. Salacup and colleagues concluded.

Reference

Salacup GFU, Everstine A, Verceles A, Grier WR, Deepak J. Environmental and military exposures among veterans and their association with lung cancer histologic subtypes. Poster #276. Presented at the American Thoracic Society 2024 International Conference; May 17-22, 2024; San Diego, California.