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How is Prostate Cancer Diagnosed?

Screening

"Screening" means testing for a disease even if you have no symptoms. The prostate specific antigen (PSA) blood test and digital rectal examination (DRE) are two tests that are used to screen for prostate cancer. Both are used to detect cancer early. However, these tests are not perfect. Abnormal results with either test may be due to benign prostatic enlargement (BPH) rather than cancer.

The American Urological Association (AUA) recommends talking with your healthcare provider about whether or not you should be screened. To find out if prostate cancer screening is a good idea, take our Know Your Stats Risk Assessment Test. Tell your results to your healthcare provider when you talk about the benefits and risks of screening.

The two main types of screenings are:

PSA Blood Test

The prostate-specific antigen (PSA) blood test is one way to screen for prostate cancer. This blood test measures the level of PSA in the blood. PSA is a protein made only by the prostate and a prostate cancer. The test can be done in a lab, hospital or healthcare provider's office.

Very little PSA is found in the blood of a man with a healthy prostate. A low PSA is a sign of prostate health. A rapid rise in PSA may be a sign that something is wrong. Prostate cancer is the most serious cause of a high PSA result. Another reason for a high PSA can be benign (non-cancer) enlargement of the prostate. Prostatitis, inflammation of the prostate, can also cause high PSA results.

A rise in PSA level does not tell us the type of cancer cells present. The rise tells us that cancer may be present.

Talk with your healthcare provider about whether the PSA test is useful for you. If you decide to get tested, be sure to talk about changes in your PSA score with your provider.

DRE

Digital Rectal Exam (DRE)

Digital Rectal Exam (DRE)
(Click image to enlarge)
Alan Hoofring (Illustrator), National Cancer Institute

The digital rectal examination (DRE) helps your doctor find prostate problems. For this exam, the healthcare provider puts a lubricated gloved finger into the rectum. The man either bends over or lies curled on his side on a table. During this test, the doctor feels for an abnormal shape or thickness to the prostate. DRE is safe and easy to do. But the DRE by itself cannot detect early cancer. It should be done with a PSA test.

Who Should Get Screened?

Screening is recommended if you are a man:

  • Between 55–69 years old
  • African–American
  • Have a family history of prostate cancer

What are the benefits and risks of screening?

The PSA test and DRE are very important tools. They help to find prostate cancer early, before it spreads. When found early, it can be treated early which helps stop or slow the spread of cancer. This is likely to help some men live longer.

A risk of a PSA test is that it may miss detecting cancer (a "false negative"). Or, the test may be a "false positive," suggesting something is wrong when you are actually healthy. A false positive result may lead to a biopsy that isn't needed. The test might also detect very slow growing cancer that will never cause problems if left untreated.

What is a Biopsy?

Transrectal prostate biopsy
Transrectal prostate biopsy
© 2005 Terese Winslow, U.S. Govt. has certain rights

Biopsy is a type of surgery.  For a prostate biopsy, tiny pieces of tissue are removed from the prostate and looked at under a microscope. The pathologist is the doctor who will look carefully at the tissue samples to look for cancer cells. This is the only way to know for sure if you have prostate cancer.

The decision to have a biopsy is based on PSA and DRE results. Your doctor will also consider your family history of prostate cancer, ethnicity, biopsy history and other health factors.

Prostate biopsy is best done with ultrasound and a probe. You may be given an enema and antibiotics to prevent infection. For the test, you will lie on your side as the probe goes into the rectum. First, your provider takes a picture of the prostate using ultrasound. Your healthcare provider will note the prostate gland's size, shape and any abnormalities. He/she will also look for shadows, which might signal cancer. Not all prostate cancers can be seen, and not all shadows are cancer. The prostate gland is then numbed (anesthetized) with a needle passed through the probe. Then, the provider removes a very small piece of your prostate. The amount of tissue removed depends on the size of the gland, PSA results and past biopsies.

If cancer cells are found, the pathologist will assign a "Gleason Score" which helps to determine the severity/risk of the disease (see Stages for more information).

After a biopsy, you may have blood in your ejaculate, urine and stool. This should go away fairly quickly. If not, or you get a fever, contact your doctor.