Women have breasts. Men have prostate. Like the breasts in a women, this male gland produces and secretes fluid.
PSA, an enzyme in the form of a glycoprotein, is a such kind of fluid concentrated in prostatic tissue. Normally, serum PSA levels are very low and high PSA levels in the blood may indicate a prostate problem. Rise of PSA may be a sign of benign growth or swelling of the prostate, as well as of prostate cancer.
Apparently, the more we know about PSA, the more we know about our prostate condition. Therefore a regular PSA test is a way to detect earlier possible problems. Many clinicians claim that incidence of death from prostate cancer has significantly decreased since the advent of PSA testing.
Of course PSA plays an important role in this situation. But there are many opinions supporting the idea that PSA is only one of many factors influencing mortality rates. Some authors concluded that the increased use of early hormone therapy has a greater impact on mortality than PSA screening.
Because randomized clinical trials have found PSA test far to be perfect, physicians should explain to prostate sufferers that its unclear if screening is a good thing or not. Most men do choose to be screened, and that's very reasonable. And the same reasonable must be the option to refuse the screening.