PROSTATE SPECIFIC ANTIGEN (PSA)
EXPLANATION IN PATIENTS WITH PROSTATE CANCER AFTER RADICAL PROSTATECTOMY

WHAT IS PSA, AND HOW DO WE MEASURE IT?
Prostate Specific Antigen is a protein that is unique or specific to the prostate. Normal prostate cells and almost all prostate cancer cells make PSA.  While most PSA is locked in the individual prostate cell (and in semen), some normally  'leaks' into the blood stream (serum).  PSA is not harmful.  These PSA levels can be measured in an individual's serum and with this information we are judge the success of treatment of prostate cancer. 

If prostate cancer spreads away from the prostate gland it will almost always continue to make PSA.  A rising PSA is usually a sign of growth of the prostate cancer.

WHAT IS THE SIGNIFICANCE OF OTHER TYPES OF PSA IF I HAVE PROSTATE CANCER?
Free PSA, Complex PSA (PSA-ACT), hK2 and other new PSA screening tests have no benefit over the currently used PSA tests in patients who already have a diagnosis of prostate cancer. They are helpful only in screening situations in helping us determine who needs or does not need a biopsy.

AFTER RADICAL PROSTATECTOMY
If the prostate gland is removed (Radical Prostatectomy) we expect the PSA level to be unmeasurable. However the PSA report will NOT say "0" or 'zero'. If the PSA level is unmeasurable, the laboratory will say "<" or ''less than'" the lowest value that a particular test can measure, for example "<0.03", "<0.1". If the "<" or "less than" is not present, it suggests that the PSA level was measurable. If any PSA is measured after radical prostatectomy, then the presence of prostate cancer cells somewhere in the body has to be suspected -but not proven until the PSA rises above 0.2 (see below under important note). If the PSA was measurable before the surgery, an unmeasurable PSA after the surgery suggests that the cancer is likely gone. Any symptoms or findings that you may have are almost certainly NOT caused by prostate cancer if the PSA is unmeasurable. If the PSA level remains unmeasurable for more than 5-7 years, the chances of the cancer returning become very very small.

One problem with the PSA is natural variability of the assays. No individual PSA can be considered concerning unless a repeat value or two confirms any elevation or presence.

Important note: Another problematic issue is that for the PSA to be truly a sign of return of the cancer, the PSA must be steadily rising and be above 0.2 ug/mL. Since many assays measure much lower than 0.2 ng/mL, we may have to watch a while until that level is reached. Patients may have values below 0.2 and stabilize and never go above this level. These patients are considered cured of their cancer. Complicated situation but one that requires close observation.