Is exposure to Agent Orange a risk factor for hepatocellular cancer?-A single-center retrospective study in the U.S....

Approximately 15% to 35% of those with chronic hepatitis C (CHC) related cirrhosis will develop hepatocellular cancer (HCC). With this burden increasing across the globe, identification of risk factors for HCC has become imperative. Exposure to Agent Orange has been implicated as a possible risk factor for liver cancer in a study from the Republic of Korea. However, there has been no study in U.S. veterans with CHC and cirrhosis that has evaluated exposure to Agent Orange as a risk factor for HCC. We conducted a retrospective study of U.S. military veterans diagnosed with CHC and cirrhosis over a period of 14 years to evaluate potential risk factors for HCC including exposure to Agent Orange.

We retrospectively reviewed 390 patients with confirmed CHC-related cirrhosis between 2000 and 2013 and identified patients with HCC. We compared demographic, laboratory, and other clinical characteristics of patients with and without HCC.

The mean age of the cohort was 51 years (SD =7.5), with the majority being male (98.5%). Seventy-nine of 390 (20.2%) patients developed HCC, diagnosed on average 8 (SD =4.8) years after diagnosis of CHC. Nearly half (49.4%) were Childs A, 40.5% were Childs B, and 10.1% were Childs C. HCC patients were more likely to be African American than non-HCC patients (40.5% vs. 25.4%, P=0.009) and to be addicted to alcohol (86.1% vs. 74.3%, P=0.027). A trend toward significance was seen in the HCC group for exposure to Agent Orange (16.5% vs. 10.0%, P=0.10) and smoking addiction (88.6% vs. 80.7%, P=0.10). Consequently, race, alcohol addiction, Agent Orange exposure, and smoking addiction were included in the multivariable logistic regression (MLR) analysis. Alcohol addiction [odds ratio (OR) =2.17; 95% confidence interval (CI), 1.07-4.43] and African American race (OR =2.07; 95% CI, 1.22-3.51) were found to be the only two definitive independent risk factors for HCC in our sample.

African American race and alcohol addiction were independent risk factors for HCC development in this U.S. veteran population. There was no significant association between exposure to Agent Orange and HCC, although larger studies are needed in the U.S. military veteran population to evaluate further this toxic herbicide from the Vietnam War era.