Prostate Cancer Screening

Posted: Sept. 1, 2004

What does "screening" mean? Screening means looking for signs of disease in people who have no symptoms. So screening for prostate cancer is looking for early-stage disease when treatment may be more effective. The main screening tools for prostate cancer are the digital rectal examination (DRE) and the prostate specific antigen (PSA) test. The DRE and PSA test cannot tell if you have cancer; they can only suggest the need for further tests.

What is the DRE?
The DRE or digital (finger) rectal examination is a quick exam for checking the health of the prostate. For this test, the doctor inserts a gloved and lubricated finger into the rectum. This allows the doctor to feel the back portion of the prostate for size and any irregular or abnormally firm areas.

What is the PSA test?
PSA stands for "prostate specific antigen." PSA is a substance produced by cells from the prostate gland and released into the blood. The PSA test measures the PSA level in the blood. A small amount of blood is drawn from the arm.
The doctor checks the blood to see if the PSA level is normal. The doctor may also use this test to check for any increase in your PSA level compared to your last PSA test.

As a rule, the higher the PSA level in the blood, the more likely a prostate problem is present. But many factors, such as age and race, can affect PSA levels. Some prostate glands produce more PSA than others. PSA levels can also be affected by:

• certain medical procedures;
• an enlarged prostate;
• a prostate infection.

Because many factors can affect PSA levels, your doctor is the best person to interpret your PSA test results.

How accurate are the screening tests?
No test is right all the time and that is true of the PSA test and DRE. The PSA test is better at suggesting that small cancers are present, especially those toward the front or sides of the prostate gland, or deep within it. But the DRE can sometimes help suggest cancers in men with normal PSA levels. That is why both the PSA test and the DRE are usually performed.

If 100 men over age 50 take the PSA test:
• 85 will have a normal PSA (though a small number of these men will have a cancer that was missed by the PSA test).
• 15 will have a higher than normal PSA and require further tests.
After further testing, results will show:
• 12 do not have prostate cancer.
• 3 have prostate cancer.

What do medical experts say about screening?
Medical experts agree that every man needs balanced information on the pros and cons of prostate cancer screening to help him make an informed decision. Balanced information is important because medical experts disagree about whether men should be screened regularly for prostate cancer.

Medical experts who encourage regular screening believe current scientific evidence shows that finding and treating prostate cancer early, when treatment might be more effective, may save lives. They recommend that all men who have a life expectancy of at least 10 years should be offered the PSA test and DRE annually beginning at age 50. They also recommend offering screening tests earlier to African-American men, and men who have a father or brother with prostate cancer.

Medical experts who do not recommend regular screening want convincing evidence that finding early-stage prostate cancer, and treating it, saves lives. They believe some of these cancers may never affect a man’s health and treating them could cause temporary or long-lasting side effects like impotence (inability to keep an erection) and incontinence (inability to control the urine flow, resulting in leakage or dribbling). Because they believe it is unclear if the potential benefits of screening outweigh the known side effects of treatment, they recommend that all men be given information on the pros and cons of screening before making their own screening decision.

Should you be screened for prostate cancer?
The decision is up to you and your doctor. Know your risk factors for prostate cancer and the pros and cons of screening.

SOURCE: U.S. Department of Health and Human Services Centers for Disease Control and Prevention (CDC)

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