Long Term Risk of Lymphoid Malignancies Among U.S. Service Members Exposed to Burn Pits in Iraq Vs. Never Deployed
Authors: Robertson Ian , Sgrignoli Robert , Dew Alexander , Darmon Sarah , Landgren Ola , Kazandjian Dickran , DeStefano Christin 
Published: December 2024

Introduction: Military service members who deployed in support of Operation Enduring Freedom (2001-2014) and Operation Iraqi Freedom (2003-2011) were at risk of burn pit exposure. Burn pits have known individual carcinogenic byproducts and as a result there is a presumptive link between deployment exposure and development of Hodgkin and non-Hodgkin lymphoma, despite a general paucity of epidemiologic data. It was previously shown that service members who deployed to Iraq and reported burn pit exposure and were followed for an average of 14 years post-deployment did not have higher rates of lymphoid malignancies than matched service members who served in Germany (Sgrignoli et al, Blood, Volume 142, Supplement 1, 2023, Page 6621). Here we report results from a 2nd comparator arm of service members who never deployed.

Methods: A retrospective cohort study was conducted to assess the prevalence of monoclonal gammopathy and long-term hematologic cancer risk in service members who deployed to Iraq and reported burn pit exposure. Data were collected from the Armed Forces Health Surveillance Division. Inclusion criteria were any service member who deployed to Joint Base Balad or Camp Taji between January 2005 to June 2007, whose deployment lasted at least 180 days, who reported burn pit exposure on their post-deployment health assessment form, who were at least 35 years old at the time of their deployment, who remained in the military for at least 10 years post-deployment, and who had post-deployment serum available in the Department of Defense Serum Repository. There were two control groups, service members who previously deployed to Germany (control group 1) and who never deployed (control group 2). Controls were individually matched to the research cohort by age (+/- 3 years), sex, branch of service, rank, and occupation category. Incident cancers with a focus on B-cell malignancies were captured via ICD-9 and -10 codes of 140-209 and C00-C96, respectively. Primary endpoint was assessment of serum monoclonal gammopathy in deployed, exposed personnel vs. the two control groups. The secondary endpoint was assessment of long-term incident development of B-cell malignancies and other cancers, which is reported here. A Fisher test was used for comparison of post-deployment malignancies between deployed/exposed service members and controls. This study was exempt from full IRB review and funded by Murtha Cancer Center Research Program.

Results: 534 deployed/exposed service members were identified. Median age at deployment was 37 (range 35-55). There were 534 and 521 service members in control groups 1 and 2, respectively. Mean follow up from the end of deployment was 14 years for deployed/exposed members and 10 years for controls. The deployed/exposed cohort had 2 hematologic malignancies, one multiple myeloma and one unspecified lymphoid neoplasm. There were no hematologic cancers diagnosed in control group 1, and there were 3 in control group 2 (1 Hodgkin disease and 2 cutaneous T cell lymphomas). There were more incident cancers in control group 2 (60 vs. 39 in the deployed/exposed and control group 1, p=0.0239). Serum monoclonal gammopathy results will be reported separately.

Conclusions: Service members who deployed to Iraq and reported burn pit exposure did not have higher rates of lymphoid neoplasms than those who served in Germany or who never deployed. Further research is needed to understand the risks of burn pit exposure on the development of B-cell malignancies and effects on the bone marrow or lymphatic tissue.

Disclaimer: The views expressed in this abstract are those of the authors and do not necessarily reflect the official policy of the Defense Health Agency, Department of Defense or the US Government. The contents of this publication are the sole responsibility of the author(s) and do not necessarily reflect the views, opinions or policies of Uniformed Services University of the Health Sciences (USUHS) and The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government.