Prostate Specific Antigen (PSA) Test
Prostate specific antigen, or PSA, test is usually performed in addition to DRE and increases the likelihood of prostate cancer detection. The test measures the level of PSA, a substance produced only by the prostate, in the bloodstream. Very little PSA escapes from a healthy prostate into the bloodstream, but certain prostatic conditions can cause larger amounts of PSA to leak into the blood. One possible cause of a high PSA level is benign (non-cancerous) enlargement of the prostate, otherwise known as BPH. Prostate cancer is another possible cause of an elevated PSA level.
The frequency of PSA testing remains a matter of some debate. The American Urological Association encourages men to have annual PSA testing starting at age 50. The AUA also recommends annual PSA testing for men over the age of 40 who are African-American or have a family history of the disease (for example, a father or brother who was diagnosed with prostate cancer). Some experts have suggested that men with an initial normal DRE and PSA level of less than 2.5 ng/ml can have PSA testing performed every two years.
Recently, several refinements have been made in the PSA blood test in an attempt to determine more accurately who has prostate cancer and who has false-positive PSA elevations caused by other conditions such as BPH. These refinements include PSA density, PSA velocity, PSA age-specific reference ranges and use of total-to-free PSA ratios. Such refinements may allow for improved increased ability to detect cancer.