Vietnam War veterans exposed to Agent Orange have increased risk of prostate cancer and even greater risks of getting the most aggressive form of the disease as compared to those who were not exposed, according to a UC Davis Cancer Center study published in the online journal Cancer. The findings are the first to reliably link the herbicide with this form of cancer by studying a large population of men in their 60s and the prostate-specific antigen (PSA) test to screen for the disease. Karim Chamie, lead author of the study and a physician in the Department of Urology and at the VA Northern California Health Care System, said that more than 13,000 Vietnam veterans were evaluated for the study.