What is a PSA Test Used For?

A PSA test is used mainly as a screening test for cancer of the prostate. In men who have been diagnosed with prostate cancer, PSA is measured to determine if the cancer has returned after surgery. It can also be used to determine whether the cancer is growing or shrinking after treatment with hormones or radiation.  

The question of whether or not to perform screening tests for prostate cancer remains controversial. PSA testing can be used to detect the earliest stage of prostate cancer, before the disease causes any symptoms. PSA testing may reduce the chance of dying from prostate cancer in some men by detecting cancer at an early age. However, there is currently no clear way to define the men who would definitely benefit from PSA testing. 

On the other hand, more often an elevated PSA level leads to over diagnosis or finds a cancer that would not affect how long a man lives or his quality of life. First, the high PSA level may be caused by some other condition, such as a benign enlarged prostate or an inflamed prostate gland. Second, most prostate cancers diagnosed after PSA screening are localized cancers that have little potential to cause harm.  

Many older men develop prostate cancer that never spreads and never causes any problems. Most of these harmless cancers would go undetected if screening was not done.