A single prostate specific antigen test taken before the age of 50 can be used to predict advanced prostate cancer in men up to 25 years in advance of a diagnosis, according to a new study. Prostate cancer is the most common cancer in American men after lung cancer. This year, more than 230,000 new cases will be diagnosed, and according to the American Cancer Society, more than 27,000 men died from prostate cancer in 2006.