The researchers studied 5,519 men aged over 55, who were participating in the
prostate cancer prevention trial, with no previous
prostate cancer diagnosis, normal DRE, and a baseline PSA of 3.0 ng/mL or less.
The study subkects were randomly assigned to finasteride, a drug commonly used to treat enlargement of the prostate gland, or placebo for seven years.
The team focused on men in the placebo group who were followed with yearly PSA tests.