The detection of prostate cancer in the United States changed dramatically with the discovery of a screening technique based on a blood test for PSA. PSA stands for prostate specific antigen.

This is a simple and inexpensive test that measures the amount of prostate specific antigen in your bloodstream. PSA is a protein made only by the prostate. Generally when a test shows higher than normal PSA levels, there's a greater chance of having prostate cancer.

The test itself does not diagnose prostate cancer and there can be many reasons other than cancer for PSA levels that are high. The PSA protein's main function is in the semen in the prostate and has no known function anywhere else in the body. If this test result comes back with a higher level than normal, then it is usually followed up by xrays or CT scans.

Previously, doctors could only screen for prostate cancer by feeling a hard lump in the gland. But this meant the cancer had to be relatively far advanced. Cancers are now diagnosed much earlier than they used to be, ten, fifteen years ago, because of PSA testing. Prostate cancer is one of the most treatable forms of cancer and especially when it is caught early enough. That is why regular prostate checkups are very important especially for men over the age of 40.