Men in their 40s and 50s who test above average for the marker for prostate cancer known as prostate-specific antigen (PSA) have a threefold chance of developing the disease later in life and may benefit from earlier screening.

"Men whose PSA was above the median were at significantly increased risk for the next 25 years for developing prostate cancer," senior author Dr. H. Ballentine Carter, a professor of urology at the Johns Hopkins University School of Medicine in Bethesda, Maryland, told Reuters Health.

PSA is a substance normally produced by the prostate gland that can serve as an indication of prostate cancer when it rises above the level of 4 nanograms per milliliter (ng/mL) of blood.

The investigators found that men who had PSA levels above the group's average levels -- but still considered within normal range -- were three to four times more likely to develop prostate cancer within the coming decades.

The average PSA level was 0.6 ng/mL for men in their 40s and 0.7 ng/mL for men in their 50s.

These results suggest that the process of developing prostate cancer begins sometime in early middle age.

Men with elevated levels of PSA may have an increased sensitivity to "male," or androgen, hormones, which increases their risk of prostate cancer. We all inherit a different ability to use and metabolize hormones. Those who use them more effectively may be at greater risk.

The American Cancer Society and the American Urological Association recommend that men begin having PSA tests to check for prostate cancer at age 50. In light of these findings it appears men may benefit from having their PSA levels tested earlier.

The author believes PSA should be tested at age 40 and 45, and then every other year at age 50. Men who are in their 40s who have levels below one range should be looked at more carefully than those who have maintained low levels.

Urology September 2001;58:411-416