NEW YORK — U.S. Air Force personnel who conducted aerial herbicide spray missions of Agent Orange during the Vietnam War had more than double the risk of monoclonal gammopathy of undetermined significance (MGUS), according to a recent report.

MGUS is a precursor to multiple myeloma, according to the study using stored blood samples from military personnel. The report was published in JAMA Oncology.1

Background information in the article noted that the cause of MGUS and multiple myeloma is unclear, although some researchers haves suggested an elevated risk of multiple myeloma among farmers and other agricultural workers, raising the possibility that pesticides could be involved.

The study, led by Memorial Sloan Kettering Cancer Center researchers, examined the association between MGUS and exposure to Agent Orange during the Vietnam War in a study sample of 958 male veterans. While 479 Operation Ranch Hand veterans were involved in aerial herbicide spray missions, they were compared with 479 veterans who were not.

The study found the overall prevalence of MGUS was 7.1% in the Operation Ranch Hand veterans vs. 3.1% in the comparison veterans, a 2.4-fold increased risk.

“Our findings of increased MGUS risk among Ranch Hand veterans support an association between Agent Orange exposure and multiple myeloma,” the study concluded.

In an accompanying commentary, Niklhil C. Munshi, MD, of the Dana-Farber Cancer Institute in Boston, wrote that the study “has brought clarity to the risk of AO [Agent Orange] exposure and plasma cell disorder. It also highlights the importance of tissue banking that allows investigation of a number of unanswered questions using modern methods. The emphasis now is to store samples from almost every major study with correlative science in mind, and this is essential if we are to understand disease biology, mechanism of response and resistance to therapy in the era of targeted therapy and precision medicine.” 2

  1. 1 Landgren O, Shim YK, Michalek J, Costello R, Burton D, Ketchum N, Calvo KR, Caporaso N, Raveche E, Middleton D, Marti G, Vogt RF Jr. Agent Orange Exposure and Monoclonal Gammopathy of Undetermined Significance: An Operation Ranch Hand Veteran Cohort Study. JAMA Oncol. 2015 Nov 1;1(8):1061-8. doi: 10.1001/jamaoncol.2015.2938. PubMed PMID: 26335650.

2 Munshi NC. Association of Agent Orange With Plasma Cell Disorder: Further Evidence. JAMA Oncol. 2015 Nov 1;1(8):1035-6. doi: 10.1001/jamaoncol.2015.3015. PubMed PMID: 26335544