Understanding What Prostate Specific Antigen (PSA) Means
By Marcel Hernandez, N.D.
The PSA: A Confusing Test
Over the years, many of the men I’ve seen as patients have had understandably emotional reactions when confronted with a high Prostate Specific Antigen (PSA) in their serum. Historically, a high PSA has been associated with prostate cancer. However, the PSA test has recently come under a lot of criticism for being over-emphasized as a diagnostic test for prostate cancer. In fact, it is quite trendy to disregard the test entirely. However, the PSA remains a useful screen that may point the way to the next step in prostate care.
In men of any age, a healthy, normal prostate releases a small amount of prostate specific antigen into the blood stream. As men age, the prostate typically enlarges and the blood level of PSA also rises. Benign prostatic hypertrophy (BPH), an enlarged prostate, is a condition that causes urinary symptoms such as decreased flow, getting up at night to urinate, difficulty in starting a stream and a feeling of incomplete voiding. BPH is the most common non-cancer condition causing PSA levels to rise.
Although the high end “normal” for PSA levels by most labs is 4.0 for men of any age, the age-based thresholds given below are much more appropriate given that BPH is common in 90 percent of men over 60 years of age.
Age (years) -- Serum PSA
40 – 49 -- 2.0
50 – 59 -- 3.0
60 – 69 -- 4.0
70 - 79 -- 5.5
Please note that these levels are used only as a guide. It is possible to have prostate cancer and have a PSA level in the normal range, although this is uncommon.
Although BPH causes an almost permanent rise in PSA, a temporary rise in the PSA can be caused by a number of conditions. Urinary tract infection, prostatitis (inflammation of the prostate), or a biopsy of the prostate can cause large rises while small rises can be caused by ejaculation and even bicycle riding. Because of these non-cancer causes of PSA elevations, many high PSA test results may be due to conditions other than prostate cancer.
The controversy regarding the usefulness of the traditional PSA has been good in that it has spawned other ways of measuring the PSA in an effort to make the test more specific for prostate cancer. One of these is called the "Free to Total" PSA, which is reported as a percent.
If the total PSA level is abnormal, the Free to Total PSA percent will give an idea of whether the rise is due to benign disease or cancer. Cancer is more likely if the Free to Total percentage is below 10 percent. This test is now available and is widely used throughout Hawaii.
What is a normal PSA level?
Most medical professionals agree that if you have a PSA greater than 4, or if your PSA is greater than the 'normal for age' range shown above, or if it is rising rapidly, you should seek further investigation.
Depending on your age and family history, your doctor may then refer you directly to a urologist, or may repeat the PSA test before referring you for further investigation.
If cancer is present, the level of PSA in the blood rises as the tumor grows. This means that small rises in PSA are found in association with small tumors that may be still confined to the prostate gland. PSA levels of 10 or less have the best chance of being localized to the gland without further spreading. If cancer is present, a prostate biopsy will reveal the characteristics of the tumor cells themselves (called Gleason Scale or "grade") and can indicate the risk that a tumor has grown beyond the prostate.
How fast do cancers grow?
Most (but not all) prostate cancers grow slowly. It can take 5 -10 years after the PSA rises above 2.5 for cancer to cause symptoms. The median survival time (period for which 50% of men survive with treatment) after the PSA starts to rise, is reported to be 17 years. For this reason, a PSA that starts to rise in an older man, say 75 - 80 years, is usually not considered to be a threat. In a man just over 50, however, a rising may be significant. These figures are presented as a guide only - the outlook for anyone diagnosed with prostate cancer depends on many clinical factors such as the nature of the tumor cells, or tumor grade, the stage of the disease and other illnesses.
High PSA levels can mean different things in different circumstances. Nevertheless, PSA levels are useful because they at the very least indicate prostate health and may indicate the risk of cancer in those who haven't yet been diagnosed.
There are a number of considerations to take into account if your PSA starts to rise. There are quite a few new developments in diagnosis and treatment. Your best bet is to find a medical provider who can help you determine your level of risk and the need for further investigation.