prostate cancer diagnostic tests

There is uncertainty and controversy about the benefits of routine screening for prostate cancer outweigh the risks for most men. Part of the problem in diagnosing prostate cancer is that the lack of early symptoms makes it hard to detect before it has spread. Another problem, according to the medical establishment, is that men don't show up dutifully for their annual digital rectal exams.
Even if they did, it might not be worth the trip. This is because the results of early-detection programs have been so disappointing, in terms of finding curable tumors, that some leading members of the medical community have concluded that mass screenings may not be worthwhile.
Although there's an ongoing effort to refine the screening methods for prostate cancer, the tests-as well as the treatment-are all highly problematic.
There are two standard tests are used for early detection of prostate cancer:

• Digital rectal examination (DRE).
• The prostate specific antigen(PSA) test.

Digital Rectal Examination
The historical view has been that rectal exams are a highly reliable means of catching most prostate cancers before they spread. Unfortunately, there's a growing body of evidence to the contrary. Study have shown that most patients have advanced diseases by the time they are diagnosed by digital rectal exam. This might be because tumors that are small and confined to the prostate may be hard to detect by rectal exam. Another major reason is that many of the cancers start on the far side of the prostate, opposite the rectum, so they can not be felt. The researchers suggested that if the digital rectal exam were performed more frequently than once a year, more of this aggressive cancer might be detected.

Prostate-Specific Antigen(PSA) test
Prostate-specific antigen is a glycoprotein enzyme produced almost exclusively by the prostate and detectable in all men who have prostates and normal levels of testosterone. The PSA test is generally better at detecting prostate cancer than a rectal exam. PSA twice as accurate the digital rectal exam in finding cancer. In fact, the PSA test might be able to indicate cancer before there's a palpable lump in the prostate. The PSA test is a sensitive diagnostic tool. However, it's so sensitive, the PSA test may give the wrong answer.PSA test results are often false negatives-that is, they are normal even if cancer is present.

A combination of digital rectal exam and PSA test may be used to help diagnose prostate cancer with more success than the sum of parts-that is, that each test can detect tumors the other two may overlook and eliminate a number of the false-positive results or at least add more informasion to the diagnosis. Positive results for either screen will lead to further prostate cancer diagnostic tests.