Pondering the Prostate Specific Antigen (PSA) Exam
All men who are 50 years old and older, as well as all men who are 40 (or older) and at risk for cancer (such as black men or men who have a family history of cancer), should have an annual PSA test, along with a rectal exam, as part of their routine physical exam. The PSA test (a relatively painless blood test) helps your doctor identify the possible presence of prostate cancer by checking for prostate specific antigen (a protein substance produced by the prostate gland), which is present in high levels in many people who have prostate cancer. Many medical professionals consider the PSA test to be as important a screening device for detecting prostate cancer among men as the mammogram is for detecting breast cancer among women.
The only thing you may need to do to prepare for the PSA test is to avoid engaging in sexual activities 24 hours before the test. Intercourse or other sexual acts as well as bicycling may artificially raise your levels of PSA, giving you a flawed test result.
Deciphering the results
PSA levels can be anywhere from zero to a thousand or more. But generally, in men who still have their prostate gland, a normal value is considered to be 4 nanograms per milliliter or lower.
Your PSA levels may affect whether the doctor chooses to order a biopsy. Even if your prostate feels okay to your doctor during your rectal exam, he may still order a biopsy if he considers your PSA level to be high. Because some men with PSA levels under 4 have prostate cancer, some doctors argue that the normal level of PSA (and the point at which doctors should consider doing biopsies of the prostate) should be lowered to 2.5 or 3 so that even more cases of cancer can be caught before they advance further.
Your doctor may also take into account your PSA velocity, which is how fast your PSA levels go up. If your PSA level was 1 last year, and now it's 2.4, your doctor has cause for concern, and more frequent testing (and even a biopsy) may be advised. To determine the frequency of the screening needed to diagnose prostate cancer, your doctor may consider the size of your prostate gland compared to your PSA level. This comparison is called PSA density. Generally, a high PSA level in a man with a small prostate is more disturbing than the same PSA level in a man with a large prostate.
An above-normal PSA test result may indicate cancer. It may also indicate prostatitis or benign prostatic hyperplasia. Frequently, above-normal PSA tests indicate "none of the above." Men can be healthy and well despite an elevated PSA.
Reviewing reliability issues
The PSA test isn't foolproof. Men with high scores (4 nanograms per milliliter or higher) don't necessarily have cancer. On the other hand, men whose scores are below the cutoff level of 4, and who would generally be screened as normal by their doctors, may actually have prostate cancer. Despite these drawbacks, the PSA is an extremely effective test that can help save lives.
Virtually any laboratory can perform a PSA test, but some labs are more efficient and careful than others. If you have a blood test, and your blood is then split up and placed into three separate vials and sent to three different laboratories, it's possible that you may receive three slightly different PSA measurements. For this reason, your doctor will order a recheck of your blood, particularly if you have an elevated PSA level, to rule out any possible lab errors. If you or your doctor is very concerned about lab error, you may wish to have your PSA level evaluated at a different laboratory than you normally use or even at the hospital, where the equipment is usually checked more carefully than at a standard lab.
A note about testing frequency
The American Cancer Society and the American Urological Society recommend annual PSA tests. However, some organizations, such as the American Academy of Family Physicians, question whether annual screenings are a good idea and worry that too many unnecessary biopsies may be performed if all men ages 50 and older are screened with PSAs. The basis for this concern is that the test isn't foolproof. In fact, if your PSA is mildly elevated (between 4 and 10), chances are that you don't have prostate cancer (about 70 percent of the time). In addition, long-term studies showing whether PSA screening saves lives have not yet been completed. Thus, some experts worry that PSA testing is a waste of money. However, you may contend that the price of the extra biopsies is well worth it. PSA tests can help identify men with prostate cancer and save lives. One qualifier: Testing and aggressive treatment may not be a good idea if a man has less than a ten-year life expectancy because he's very elderly or he's in poor medical shape. Prostate cancer often grows slowly, so a less aggressive approach is probably okay in this circumstance.