Prostate cancer screening is an attempt to identify individuals with prostate cancer in a broad segment of the population—those for whom there is no reason to suspect prostate cancer. There are currently two methods used: One is the digital rectal examination (DRE), in which the examiner inserts a gloved, lubricated finger into the rectum to examine the adjoining prostate. The other is the prostate-specific antigen (PSA) blood test, which measures the concentration of this molecule in the blood. Screening is controversial. Prostate cancer can develop into a fatal, painful disease, but it can also develop so slowly that it will never cause problems during the man's lifetime...