Prostate-specific antigen (PSA) is detected in the bloodstream through a simple blood test. A PSA test for prostate cancer blood sample is drawn from a vein in the arm and sent to a laboratory for analysis. The PSA test for prostate cancer is very sensitive for indentifying potential problems that might be occurring in the prostate gland, especially diseases for prostate cancer. Abnormal levels of prostate-specific antigen often indicate that prostate cancer, and PSA testing allows doctors to assess a man’s prostate cancer risk.
Different PSA Tests for Prostate Cancer provide slightly differing results. Even within a laboratory, there can a variation in the PSA level found, depending upon the manufacturer of the test kit. And there is typically day-to-day variation in PSA in the body in all men.
Factors that may cause the PSA level of a PSA test for prostate cancer to rise include medical procedures such as cystoscopy, a test in which a slender tube with a lens and a light is used to see the bladder and urethra, prostate biopsies, vigorous prostatic massages, which are sometimes used to treat prostatitis, and transrectal ultrasound (TRUS). However, a digital rectal examination (DRE) should not have any significant effect on the level of prostate-specific antigens in your PSA test, so prostate cancer can still be confirmed should, a blood sample be collected after an abnormality is felt during a DRE.
There are some activities that may affect the level on a PSA test. For prostate cancer to be assessed correctly, your doctor may recommend some restrictions before your PSA test for prostate cancer, such as no vigorous bicycle or motorcycle rides and no sexual activity, specifically ejaculation, 1 to 2 days before your PSA Testing. Prostate cancer can be hidden or masked by some drugs or herbal supplements. They may falsely lower the level on a PSA test. For prostate cancer to be assessed correctly, tell your doctor if you are taking the following:
- Finasterie (Proscar)
- Finasteride (Propecia)
- Dutaseride (Avodart)
- Any herbal for “prostate health”
An abnormally high level of prostate-specific antigen is often a strong indicator that a man has prostate cancer. PSA testing thus allows doctors to assess a man’s risk for, prostate cancer and although PSA testing cannot determined the presence or absence of prostate cancer, at the very least, it serves as a screening device that can indicate that a prostate problem might exist.
Generally, when there is a very high level of PSA on a PSA test, prostate cancer is present, and most likely has spread beyond the prostate. The higher the PSA level, the larger the prostate cancer, and while PSA Tests alone do not provide enough information to distinguish between benign prostate conditions and cancer, doctors can use the results of PSA tests, along with other factors, to then decide whether additional testing is necessary.
Variations in PSA Testing and Prostate Cancer
There have been some recent developments in prostate cancer PSA testing methods, which may provide more information and detail, allowing doctors to more accurately identify men who need biopsies. However, not all doctors interpret results in the same way. Still considered investigational support, these are the additional PSA tests and their prostate cancer detection aspects:
- Percent-Free PSA, or free-to-total PSA:
PSA occurs as two major forms in the blood. Most PSA is attached to blood proteins, which are called “bound” PSA, while the other PSA circulates unattached, and is considered “free.” A new variation prostate cancer PSA testing looks at PSA in the bloodstream to determine how much is inherent to protein and how much is not. This bound PSA versus free PSA is calculated into a free-to-total (bound plus free) PSA ratio, and is called a percent-free PSA test. For prostate cancer, the lower the number, the more likelihood that cancer is the cause of the total PSA elevation, because cancer produces more attached PSA. Tests for prostate cancer like the percent-free PSA, may help distinguish men with prostate cancer from those with benign conditions.
If your PSA results are in the borderline range of 4-10 ng/ml, and you have a low ratio on your percentage-free PSA Test, your prostate cancer likelihood is about 50%, and your doctor will want to do a biopsy of your prostate gland. In fact, many doctors recommend biopsies when the percent-free PSA is 25% or less.
Although this PSA test may narrow the number of abnormal PSA levels found in men without cancer, there are, several concerns exist regarding percent-free PSA tests and prostate cancer evaluation. Since free PSA is less stable than bound PSA, a laboratory’s handling of specimens can affect results. Also, the diversity of manufacturers’ tests can provide a vast difference of free-to-total ratios. Because of these factors, there are now efforts underway to develop measurements for the bound form of PSA.
- Complexed PSA test:
Another PSA Test for Prostate Cancer is the complexed PSA test, or cPSA, and is another way of analyzing the separation of bound and free PSA. Tests for prostate cancer, in this case, measuring how much PSA is bound, is very useful for doctors because it helps them to better detect prostate cancer. Men with prostate cancers typically have a greater fraction of bound PSA in their total PSA. The complexed PSA test for prostate cancer, as a single test, has proven better at detecting prostate cancer than the regular PSA test and shown to be comparable to percent-free PSA testing. And prostate cancer, in one study, was found more effectively for men with PSA levels between 2.5 and 4.0. The potential advantage of this new PSA test for prostate cancer is that it involves only one blood test and thus is more cost-effective. However, the disadvantages are that it does not tell us the percent-free PSA level, which is useful in eliminating the aggressiveness of cancer, and as with the regular PSA test, the complexed PSA test can still provide misleading information if there is an infection and inflammation of the prostate.
- PSA Density:
A higher PSA density usually means a greater chance of prostate cancer. PSA testing for density may be useful for your doctor’s evaluation, although the percent-free PSA test has so far shown to be more accurate. Through a transrectal ultrasound, your doctor will determining the size of your prostate, and then by dividing the PSA number by the prostate volume, he can determined your PSA density. This calculation helps doctors adjust for the fact that some men have larger prostates than others and thus should be considered to have higher “normal” PSA levels.
- PSA Velocity:
Another promising new approach to the PSA test for prostate cancer is to look at how quickly a man’s PSA level rises over time. This diagnostic approach uses regular PSA testing to analyze the velocity of PSA, or the rate of its change from year to year. The advantage to PSA velocity is not a separate PSA test for prostate cancer. However, since it evaluates the change of PSA values over time, if a man has a slightly elevated PSA level, his doctor may want to repeat PSA tests several months later, in order to follow his PSA’s rate of increase. The theory behind this approach is that the PSA level in men with prostate cancer will usually show an increase in PSA at a greater rate than men without prostate cancer. PSA tests should be obtained during a two-year period, at least 18 month apart. It is not been found to be helpful to have two PSA tests in a shorter time span, because there is a natural fluctuation in PSA readings that may be as much as 15 to 30% in just a couple of months. Although, a man’s PSA levels for may change for a variety of reasons, other than the development of prostate cancer, it is nonetheless, important to keep an eye on the velocity of your PSA scores of time.
When To Have A PSA Test for Prostate Cancer
Most men have a PSA test for prostate cancer every year starting at age 50, which most experts feels is adequate. PSA testing for prostate cancer more often does not appear to help, while a less often PSA test may let prostate cancer grow too long undetected. If you are in a high risk group, such as having a family history of prostate cancer (in which your father, brother, uncle or grandfather had prostate cancer), or being African-American, then you should start our annual checks at age 40. However, you should discuss with your doctor whether or not you should be screened for prostate cancer with PSA tests. Your doctor will help you consider your options based on your individual situation, and discuss the pros and cons of the different PSA tests for prostate cancer.
