The introduction of the prostate specific antigen (PSA) test in 1986 ushered in a new era in prostate cancer detection and treatment. With the ability to find cancer up to six years earlier than with a digital rectal exam, PSA testing has resulted in more men than ever being diagnosed with tumors still in an early, localized, and curable stage. Before the PSA test was introduced, more than half of prostate cancers were not detected until they had already advanced beyond the prostate; but today, the majority of cancers (about 70%) are still localized when they are detected.

Even though prostate cancer mortality rates have fallen by 6% since 1992, it is unclear whether this decrease is due to the widespread use of PSA. A positive effect is suggested by the fact that groups of men who are more intensively screened (for example, white men) have had a more significant decrease in mortality than those not as heavily screened (for example, black men). Still, experts remain divided on the appropriateness of PSA screening in men with no symptoms of prostate cancer. While acknowledging that screening improves the odds of detecting curable cancer, some contend that many of these cancers are inconsequential -- which means that many men undergo needless, and potentially harmful, treatments. To address such concerns, researchers have developed -- and continue to work on -- refinements to the PSA test.

Recommendations for Testing

The American Urological Society, the American Cancer Society, and the American College of Physicians recommend that prostate cancer screening be discussed with all men over age 50 and with high-risk men -- that is, black men or any man with a family history of prostate cancer -- over age 40 to 45. In general, a PSA value of 4 ng/mL is considered the cut-off for suspected cancer (although it may vary slightly by age), and levels above 10 ng/mL indicate very high risk. It is values between 4 and 10 ng/mL that are the most ambiguous; men in this range may benefit most from refinements in the PSA test. The risk of cancer based on PSA levels follows:

PSA levels under 4 ng/mL: "normal"
4 to 10 ng/mL: 20 to 30% risk
10 to 20 ng/mL: 50 to 75% risk
Above 20 ng/mL: 90%.