Weighing the benefits, limitations and potential risks of the PSA test can help you make an informed decision.
Benefits of the test
A PSA test may help detect prostate cancer at an early stage. Cancer is easier to treat and is more likely to be cured if it's diagnosed in its early stages.
But to judge the benefit of the test, it's important to know if early detection and early treatment will improve treatment outcomes and decrease the number of deaths from prostate cancer.
A key issue is the typical course of prostate cancer. Prostate cancer usually progresses slowly over many years. Therefore, a man may have prostate cancer that never causes symptoms or becomes a medical problem during his lifetime.
Limitations of the test
The limitations of PSA testing include:
- PSA-raising factors. Besides cancer, other conditions that can raise PSA levels include an enlarged prostate (benign prostatic hyperplasia, or BPH) and an inflamed or infected prostate (prostatitis). Also, PSA levels normally increase with age.
- PSA-lowering factors. Certain drugs used to treat BPH or urinary conditions may lower PSA levels. Large doses of certain chemotherapy medications can also lower PSA levels.
- Misleading results. The test doesn't always provide an accurate result. An elevated PSA level doesn't necessarily mean you have cancer. And in some cases, a normal PSA level does not completely rule out prostate cancer.
- Overdiagnosis. Studies have estimated that between 17 and 50 percent of men with prostate cancer detected by PSA tests have tumors that wouldn't result in symptoms during their lifetimes. These symptom-free tumors are considered overdiagnoses — identification of cancer not likely to cause poor health or to present a risk to the man's life.
The potential risks of the PSA test are essentially related to the choices you make based on the test results, such as the decision to undergo further testing and treatment for prostate cancer. The risks include:
- Biopsy issues. A biopsy is a procedure that carries its own risks, including pain, bleeding and infection.
- Psychological effects. False-positive test results — high PSA levels but no cancer found with biopsy — can cause anxiety or distress. If you are diagnosed with prostate cancer, but it appears to be a slow-growing tumor that doesn't result in illness, you may experience significant anxiety just knowing it's there.
A number of major professional organizations and government agencies have weighed in on the benefits and risks of PSA testing. The American Cancer Society, the American Urological Association, the American College of Preventive Medicine, the Centers for Disease Control and Prevention, and the U.S. Preventive Services Task Force all recognize the controversy surrounding screening with the PSA test and the lack of firm evidence that screening can prevent deaths from prostate cancer. Other points of agreement include:
- Screening needs to be an individualized decision. All of the organizations recommend that doctors discuss the benefits and risks of PSA testing with men at a certain age or in high-risk groups. Doctors should help men make their own decisions about screening, based on age, risk factors, life expectancy and personal preferences.
- Older men may not need to be screened. Some organizations recommend that screening isn't necessary for men age 75 and older or those who aren't expected to live more than 10 years. The American Cancer Society advises that this decision should be made on an individual basis. It is very important, however, to keep in mind that decisions need to be individualized and not assume that all prostate cancer screening must stop once a man is in his 70s.
- Men at high risk should discuss screening at an earlier age. Some groups recommend earlier discussions for men in high-risk groups — those with a family history of prostate cancer and African-American men.
The American Cancer Society recommends that doctors provide information about prostate cancer screening to men at average risk starting at age 50, while men at higher risk could benefit from this information at age 40 or 45. The American Urological Association recommends that men consider getting a baseline prostate cancer screening, including a PSA test and DRE, beginning at age 40.
The American Urological Association (AUA) recommends against PSA screening in men under age 40, and it doesn't recommend screening between ages 40 and 54 for men at average risk. For men ages 55 to 69, the AUA recommends shared decision-making between men and their doctors about when to begin screening. The AUA guidelines state that the greatest benefit of screening appears to be in men ages 55 to 69, and it does not recommend routine screening beyond age 70.
The U.S. Preventive Services Task Force (USPSTF) recommends against PSA-based screening for men who do not have symptoms that are highly suspicious for prostate cancer. The USPSTF states that PSA testing in healthy men, regardless of age, offers no net benefit or that the harms outweigh the benefits. This has been a very controversial point of view, and many experts in the field of prostate cancer do not agree with the USPSTF recommendations.
May 07, 2013
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