Consider the benefits and limitations of a PSA test when choosing whether to undergo prostate cancer screening.

By Mayo Clinic Staff

Weighing the benefits, limitations and potential risks of the prostate-specific antigen (PSA) test for prostate cancer can help you make an informed decision.

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.

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.

Discuss the benefits with your doctor. Together you can decide whether PSA testing is right for you.

Mar. 28, 2014