Main Objective
To see whether the drug finasteride (Proscar™) can prevent prostate cancer in men age 55 and older.

Enrollment Period
October 1993 - May 1997

Participants
18,882 men: 92 percent white, 4 percent African American, 4 percent other races/ethnicities

Intervention
Men were randomly assigned to take either 5 milligrams of finasteride or a placebo (dummy pill) once daily for seven years. All men had an annual digital rectal exam and prostate-specific antigen (PSA) test. At the end of the seven years, men who had not been diagnosed with prostate cancer were asked to have a prostate biopsy to see if they were truly cancer free.

Criteria for Participation

• Men, age 55 and older
• General good health
• No evidence of prostate cancer at beginning of trial
• Prostate Specific Antigen (PSA) 3 ng/ml
• Willing to have a prostate biopsy at the end of the study

Study Sites
222 centers, located in the United States and Canada

Additional Study Objectives

• To determine if finasteride affects the stage and grade of prostate cancers
• To see if finasteride affects the number of deaths from prostate cancer and the number of deaths from all cancers
• To see if finasteride changes the occurrence and type of noncancerous prostate growth
• To estimate the accuracy of digital rectal exam and PSA testing -- separately and together -- in detecting whether a man has prostate cancer
• To measure how long-term treatment with finasteride affects a man's urinary and sexual function