FAIRFIELD, CA – Does trauma play a role in the development of blood cancer? A recent study of wounded warriors sought to answer that question.
A presentation at the 61st American Society of Hematology Annual Meeting and Exposition in Orlando recounted that multiple case reports have described lymphomas and plasma cell neoplasms that developed after trauma.1
The study team, led by researchers from the David Grant U.S. Air Force Medical Center, explained how hypotheses suggest that trauma-induced inflammation might contribute to the neoplasia, with the site of trauma serving as the nidus (locus minoris resistentiae).
“However, to our knowledge there are no studies demonstrating causality,” noted the authors, who included researchers from the Uniformed Services University of the Health Sciences and the National Institutes of Health, both in Bethesda, MD, and the VA Salt Lake City, UT, Health Care System. “Traumatic injuries sustained during combat have been linked with higher rates of hypertension, coronary artery disease, diabetes mellitus and chronic kidney disease. Whether severe injury also increases the risk of hematologic malignancies is unknown.”
The authors hypothesized that combat injured veterans have higher rates of lymphoma and plasma cell dyscrasias compared to non-injured combat veterans.
For the retrospective cohort study, information about 9,654 U.S. military personnel injured during combat operations in Iraq or Afghanistan from 2002-2015 was extracted from the DoD Trauma Registry. Patients were excluded if they died in theater, had multiple battle injuries, had pre-existing cancer diagnoses or missing data.
Researchers also used a cohort of 9,654 deployed and uninjured Iraq and Afghanistan combat veterans, obtained from the MHS Data Repository and matched for age, branch of service, and sex, for comparison.
Cancer diagnoses were defined using International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) Clinical Modification codes obtained from both the DoD and the VHA through the MDR and the Veterans Informatics and Computing Infrastructure, respectively.
Malignancy classifications by ICD codes were broken down into aggressive B-cell lymphomas, indolent B-cell lymphomas, Hodgkin lymphoma, T-cell lymphomas and plasma cell dyscrasias.
The mean age of participants was 26, with most patients being junior enlisted personnel in the Army, males and of non-Hispanic white ethnicity/race. The average post-trauma follow-up time was 5.3 years.
Results indicated that overall rates of aggressive B-cell lymphomas, indolent B-cell lymphomas, Hodgkin lymphoma, T-cell lymphomas and plasma cell dyscrasias were low, and there were no statistically significant differences in incidence rates between the two cohorts.
“Traumatic injuries can activate innate immune responses involving inflammatory cytokines, complement, coagulation and dendritic cells, resulting in a pro-inflammatory state,” the researchers explained. “Preclinical studies reveal that such inflammation may hamper T-cell immune-surveillance needed to eradicate malignancy. However, in our cohort of severely injured combat veterans, rates of lymphomas and plasma cell dyscrasias were not increased over un-injured combat veterans.”
The authors said the strengths of their study included a “well-characterized cohort with a matched comparator arm enabling vigorous examination of the impacts of traumatic injuries on cancer. Limitations include retrospective design and relatively short follow up. It is possible that differences will emerge with longer follow up.”
Researchers concluded that, despite critical combat trauma injuries being associated with a heightened risk of multiple chronic comorbidities, those injuries do not appear to heighten the risk of lymphoid or plasma cell neoplasms within the first five years.
- Destefano C, Shaw K, Stewart I, Polavskiy E, et. al. Does Trauma Heighten the Risk of Hematologic Malignancies? a Retrospective Study of U.S. Combat Veterans? Presented at the 61st American Society of Hematology Annual Meeting and Exposition; December 2019; Orlando, FL
