Prostate cancer screening: Should you get a PSA test?

Making the decision to have a PSA test depends on a variety of factors. Here are some tips that can help you make a good decision. By Mayo Clinic Staff

Cancer screening tests — including the prostate-specific antigen (PSA) test to look for signs of prostate cancer — can be a good idea. Prostate cancer screening can help identify cancer early on, when treatment is most effective. And a normal PSA test, combined with a digital rectal exam, can help reassure you that it's unlikely you have prostate cancer. But getting a PSA test for prostate cancer may not be necessary for some men, especially men 75 and older.

Professional organizations vary in their recommendations about who should — and who shouldn't — get a PSA screening test. While some have definitive guidelines, others leave the decision up to men and their doctors. Organizations that do recommend PSA screening generally encourage the test in men between the ages of 40 and 75, and in men with an increased risk of prostate cancer.

Ultimately, whether you have a PSA test is something you should decide after discussing it with your doctor, considering your risk factors and weighing your personal preferences.

Here's more information to help you prepare for a conversation with your doctor about PSA testing.

Simple test, not-so-simple decision

There are a number of pros and cons to the PSA test.

Pros of PSA screening Cons of PSA screening
PSA screening may help you detect prostate cancer early. Some prostate cancers are slow growing and never spread beyond the prostate gland.
Cancer is easier to treat and is more likely to be cured if it's diagnosed in the early stages of the disease.

Not all prostate cancers need treatment. Treatment for prostate cancer may have risks and side effects, including urinary incontinence, erectile dysfunction or bowel dysfunction.

PSA testing can be done with a simple, widely available blood test.  PSA tests aren't foolproof. It's possible for your PSA levels to be elevated when cancer isn't present, and to not be elevated when cancer is present.
For some men, knowing is better than not knowing. Having the test can provide you with a certain amount of reassurance — either that you probably don't have prostate cancer or that you do have it and can now have it treated. A diagnosis of prostate cancer can provoke anxiety and confusion. Concern that the cancer may not be life-threatening can make decision making complicated.
The number of deaths from prostate cancer has gone down since PSA testing became available. It's not yet clear whether the decrease in deaths from prostate cancer is due to early detection and treatment based on PSA testing or due to other factors.

What is PSA?

Prostate-specific antigen (PSA) is a protein produced by both cancerous (malignant) and noncancerous (benign) prostate tissue. PSA helps liquefy the semen. A small amount of PSA normally enters the bloodstream. Prostate cancer cells usually make more PSA than do benign cells, causing PSA levels in your blood to rise. But PSA levels can also be elevated in men with enlarged or inflamed prostate glands. Therefore, determining what a high PSA score means can be complicated.

Besides the PSA number itself, your doctor will consider a number of other factors to evaluate your PSA scores:

  • Your age
  • The size of your prostate gland
  • How quickly your PSA levels are changing
  • Whether you're taking medications that affect PSA measurements, such as finasteride (Propecia, Proscar), dutasteride (Avodart) and even some herbal supplements

When elevated PSA isn't cancer

While high PSA levels can be a sign of prostate cancer, a number of conditions other than prostate cancer can cause PSA levels to rise. These other conditions could cause what's known as a "false-positive" — meaning a result that falsely indicates you might have prostate cancer when you don't. Conditions that could lead to an elevated PSA level in men who don't have prostate cancer include:

  • Benign prostate enlargement (benign prostatic hyperplasia)
  • A prostate infection (prostatitis)
  • Other less common conditions

False-positives are common. Only about 1 in 4 men with a positive PSA test turns out to have prostate cancer.

When prostate cancer doesn't increase PSA

Some prostate cancers, particularly those that grow quickly, may not produce much PSA. In this case, you might have what's known as a "false-negative" — a test result that incorrectly indicates you don't have prostate cancer when you do. Because of the complexity of these relating factors, it's important to have a doctor who is experienced in interpreting PSA levels evaluate your situation.

What's the advantage of a PSA test?

Detecting certain types of prostate cancer early can be critical. Elevated PSA results may reveal prostate cancer that's likely to spread to other parts of your body (metastasize), or they may reveal a quick-growing cancer that's likely to cause other problems.

Early treatment can help catch the cancer before it becomes life-threatening or causes serious symptoms. In some cases, identifying cancer early means you will need less aggressive treatment — thus reducing your risk of certain side effects, such as erectile dysfunction and incontinence.

May. 07, 2013 See more In-depth