Military Exposures and Small Cell Lung Cancer in Veterans

BALTIMORE — Military service often places individuals in environments where they may be exposed to hazardous substances with potential for long-term consequences. A particularly concerning health outcome for veterans exposed to Agent Orange, burn pits and other environmental toxins common during military service is small cell lung cancer.

SCLC is an aggressive form of lung cancer characterized by small, round cells that multiply rapidly. SCLC has two main subtypes, small cell carcinoma (often referred to as oat cell cancer because it looks like oat flakes under a microscope), the classic and more common form of SCLC and combined small cell carcinoma, which features a mix of small cell and non-small cell lung cancer cells.

Both subtypes are recognized by the VA as presumptive cancers for certain Vietnam, Gulf War, post-9/11 and other veterans. This designation means that veterans diagnosed with these conditions are assumed to have developed the disease as a result of their service-related exposures, qualifying them for VA health benefits and disability compensation.

Those included in the presumptive coverage for SCLC include “atomic veterans,” who may have been exposed to ionizing radiation during the occupation of Japan while held as a prisoner of war in Japan or through nuclear weapons testing, while working at Long-Range Navigation stations or at McMurdo Station in Antarctica’s nuclear power plant. In addition, the Sergeant First Class Heath Robinson Honoring our Promise to Address Comprehensive Toxics Act of 2022, known as the Honoring our PACT Act of 2022, added servicemembers involved in the clean-up operations on Enewetak Atoll; in Palomares, Spain; and on Thule Air Force Base in Greenland.

SCLC is also presumed to be service-related in veterans deployed in Vietnam, Cambodia, Laos, Thailand, Guam, American Samoa, Johnston Atoll, the Korean demilitarized zone or who regularly served aboard or maintained a C-123 aircraft used for spraying herbicides. All of these individuals are assumed to have sustained exposure to Agent Orange.

Burn Pit Exposure Increased SCLC Risk for Younger Veterans

Veterans who served in combat zones during and after the Gulf War or the post-9/11 period were often exposed to a variety of substances that could damage lungs or contribute to the development of lung malignancies in later life and SCLC in this cohort is also a presumed condition.

Burn pits have been a central focus in understanding veterans’ exposure to toxic substances. These open-air disposal sites were widely used in combat settings to incinerate everything from plastics and electronics to human waste and chemicals, creating thick, toxic smoke that directly affected burn pit workers. Smoke drift also exposed others at the site to the toxins.

The pits were used in areas where other methods of waste disposal were impractical. However, the incomplete combustion of materials in these pits led to the release of harmful chemicals, including volatile organic compounds (VOCs), such as benzene and dioxins, which are known carcinogens. Burn pits also released polycyclic aromatic hydrocarbons (PAHs), which can cause lung cancer upon prolonged exposure. In addition, the fires, materials and environmental setting generated a great deal of particulate matter, which can damage lung tissue and contribute to the development of cancer.

The exposure to these hazardous materials was often prolonged, with many veterans experiencing daily or near-daily exposure during deployments. Studies have linked exposure to these toxins with an increased risk of respiratory illnesses, including lung cancers of all types.

Many of these exposures occurred in specific locations known to have had a higher risk of contamination, including Afghanistan, Djibouti, Egypt, Jordan, Lebanon, Syria, Uzbekistan, Yemen and the airspace above these areas after Sept. 11, 2001. Veterans of previous conflicts in Southwest Asia, including those serving in Bahrain, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, Somalia, the United Arab Emirates (UAE) and the airspace above these areas after Aug. 2, 1990, are also considered at high risk.

Other locations of concern include the Arabian Sea, Gulf of Aden, Gulf of Oman, the neutral zone between Iraq and Saudi Arabia, the Persian Gulf and the Red Sea. Veterans who served in these areas are presumed to have been exposed to burn pits and other toxins and thus to have a higher likelihood of developing diseases such as SCLC as a result of their service, though the malignancy might not develop for decades.

Many veterans also regularly encountered other environmental toxins that increase the risk of SCLC, such as particulate matter, chemicals from munitions and industrial emissions as well as common occupational hazards in military work including diesel exhaust, solvents and chemical agents.

Exposures, Period of Service and Lung Cancer Type

To better understand the association of lung cancer histological subtypes and specific exposures among veterans, a recent VA study analyzed service locations and exposures among veterans seen in the lung mass clinic at the Baltimore VAMC between 2015 and 2022.¹

“Veterans’ unique occupational, operational and environmental exposures during and post service constitute additional risk factors,” Grace Faith Salacup, MD, of the Baltimore VAMC and the division of Pulmonary, Critical Care and Sleep at the University of Maryland School of Medicine and colleagues noted.

The analysis included 293 veterans with cancer who had an average age of 69.3 +/- 7.7 years. The study population was 96.3% male, 53.6% white, 44.7% Black and 1.7% other. Of the participants, 57.3% were former smokers, 40.3% were current smokers, and 2.4% had never smoked. Among the smokers, 91.5% currently or previously smoked at least 20 packs of cigarettes per year.

Consistent with the age of the veterans in the study, 65% served in Vietnam, 9% in Korea, 6% were Persian Gulf War veterans, and 20% were locally deployed or served elsewhere. The most common exposures were asbestos (170), Agent Orange (111) and radiation (103). Twenty-six participants in the study reported exposure to oil fumes, 25 to pesticides and 11 to burn pits, with these lower numbers in keeping with the age and location of service of the veterans studied.

Nine percent of the veterans had SCLC, 85% had non-small cell lung cancer (NSCLC) and 6% had no tissue analyzed or were lost to follow-up.

At diagnosis, 32.76% of the veterans had stage I cancer, 11.95% had stage II, 26.28% had stage III, and 22.53% had stage IV disease. The researchers did not break down the stage at diagnosis by type of lung cancer.

Their analysis revealed that after adjusting for smoking history, Agent Orange exposure quadrupled the relative risk of developing SCLC (RR:4.17, 95% CI: 1.03-16.87, p 0.045).

“As a single-center case control study, these exposures cannot establish causality to a specific type of lung cancer and/or bronchiolitis,” the researchers noted. However, they did find “burn pit exposure is associated with increased odds of bronchiolitis in histopathology (OR 6.14 CI: 1.06 35.55, p 0.043).” Bronchiolitis, a chronic lung inflammation, elevates the risk of SCLC. The 19 veterans with bronchiolitis in the study also had SCLC, though the study did not identify the timing of their diagnoses.

Based on these findings, the researchers recommended “education and training among the VA providers on standardizing exposure screening among veterans in their clinic visits” and development of a standardized questionnaire to enable objective quantification of exposures.

 

1. Salacup C, Roberson R, Kenyon J, Segal J, Fagan K. Occupational, operational, and environmental exposures in veterans: the implications for small cell lung cancer. Poster presented at University of Maryland School of Medicine; 2024.