The impact of Agent Orange exposure on presentation and prognosis of patients with chronic lymphocytic leukemia.

Exposure to Agent Orange (AO) and the contaminating chemical 2,3,7,8-tetrachlorodibenzodioxin (TCDD) has been associated with the development of chronic lymphocytic leukemia (CLL). Of the 195 veterans diagnosed with CLL from 2001 to 2010 in a retrospective cohort from the Minneapolis Veterans Affairs Medical Center, 33 (17%) were exposed to AO. Prognostic factors including Rai stage, lymphocyte doubling time and cytogenetics did not differ between exposed and unexposed patients. Exposed patients were younger at diagnosis (61 vs. 72 years, p < 0.0001) and time to CLL treatment was shorter (9.6 vs. 30.2 months, p = 0.02). Overall survival did not differ between exposed and unexposed patients on Kaplan-Meier analysis, but when adjusted for age, AO exposure had a hazard ratio of death of 1.8 compared to non-exposure (95% confidence interval 0.7-4.5, p = 0.24). The high estimate of the mortality hazard combined with the relatively low numbers in the exposure group suggests that further examination in a larger patient population is warranted.