A prostate-specific antigen, or PSA, test can find signs of cancer for early treatment. It is not necessary for some men and may even lead to overtreatment. Men should discuss the need for a test with a doctor, based on risk factors, and find a medical professional experienced in PSA screening.

Professional organizations differ on when men should consider a PSA test. Men who have risk factors for prostate cancer, such as older age, family history, and obesity, might be recommended to have screenings between ages 40 and 75.

Not all prostate cancers need treatment and may not spread beyond the prostate gland because of slow growth, according to the Mayo Clinic. PSA tests also can be an unreliable indicator of cancer, sometimes showing elevated PSA levels when cancer is not present or not detecting higher levels when cancer is present.

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However, PSA tests can help detect the cancer at a stage crucial for early treatment when it is easier to treat. The screening is done simply through a blood test. The Mayo Clinic pointed out that although deaths from prostate cancer have decreased since PSA testing became available, it is not clear if this is due to the tests or other factors.

Doctors use complicated guidelines when determining results from a PSA test, which measures the possibility of cancerous tissue produced by the PSA protein. Doctors consider a man’s age, the size of the prostate gland, changes in the PSA levels, and if certain medications affected the results.

If a PSA test suggests that cancer is a possibility, doctors may perform a prostate biopsy, taking multiple samples of prostate tissue. Ultrasound may also be used. A pathologist determines if cancer is present from the biopsied tissue.

Tumors may be found that are not life-threatening, according to the National Cancer Institute. This can lead to unnecessary treatment and the risk of harmful side effects, such as urinary incontinence, erectile dysfunction or bowel dysfunction.

When PSA levels are high, doctors might recommend that the patient wait before having the test done again because other factors can increase the levels. An enlarged prostate, older age, prostatitis, certain medications and even riding a bicycle can affect the results of PSA levels, according to the American Cancer Society.

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Diuretics, aspirin, cholesterol-lowering medicine, herbal mixtures and obesity are among the factors that can cause lower PSA levels even when cancer is present. All these factors need to be discussed with a doctor when considering a PSA test and after undergoing one.

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