Test May Predict Prostate Cancer

A new blood test holds promise of predicting possible cases of prostate cancer up to 10 years before the disease can be diagnosed, a six-year jump on current methods, scientists reported. The new test involves a different way of monitoring the enzyme PSA, or prostate specific antigen, in a man’s blood, according to researchers at the National Institute on Aging and the Johns Hopkins University School of Medicine. “Currently, most physicians test for total PSA only, which, when measured repeatedly over time, can predict prostate cancer up to four years before clinical diagnosis,” Dr. James Fozard of the institute said. “This study, however, shows that measuring the ratio of free to total PSA repeatedly over time may lead to predictions of prostate cancer up to 10 years before clinical diagnosis of prostate cancer.” PSA is found in high concentration in semen, but it also leaks into the blood stream when the prostate enlarges. Part of the PSA binds to the protein ACT, and comparing the levels of free and bound PSA is the essence of the new test.