Healthy men who want to prevent prostate cancer should begin taking finasteride, a drug used to treat prostate enlargement symptoms and baldness, according to new guidelines made by the American Society of Clinical Oncology and American Urological Association.

The guidelines are scheduled to appear in the March issues of the Journal of Clinical Oncology and The Journal of Urology.

The two medical groups said that taking finasteride, a drug widely used to treat male pattern baldness and urological problems, can reduce the risk of developing prostate cancer by as much as 25 percent.

"The goal of developing a chemo-preventive agent that can reduce the risk of prostate cancer has been achieved, and that is a major achievement," National Institutes of Health scientist Barnett Kramer, who headed the group of scientists that issued the guidelines, said.

The guidelines are based on 15 medical studies (including the large Prostate Cancer Prevention Trial). They involved over 18,000 men aged 55 and older. The recommendation targets men with a normal reading on the prostate-specific antigen or PSA test, which is considered the best indicator of the presence of a tumor. Clinical trials leading to this recommendation covered only such men.

The new guidelines come to the rescue of so many men at risk of developing prostate cancer. Annually, the disease is diagnosed in approximately 220,000 men in the United States. About 28,000 of them die, which makes prostate cancer the most common cancer and second-leading cancer killer among men.