A panel of medical experts issued a near-failing grade for a popular test used to screen men for prostate cancer. The PSA test received a D from The U.S Preventive Services Task Force, which said that the risks of false-positives outweighed the benefit of early detection. "Many men are being subjected to the harms of treatment of prostate cancer that will never become symptomatic," the task force stated. "PSA-based screening for prostate cancer results in considerable overtreatment and its associated harms." Most men have PSA tests, which measure a protein in the blood that could be a sign of cancer, beginning at age 50. Positive tests usually prompt biopsies and cancer treatment, which does not always prove necessary. The ruling published Monday in the Archives of Internal Medicine could affect millions of men.