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Prostate cancer screening: Should you get a PSA test?
 By Mayo Clinic staff - November 9, 2012
 <http://www.mayoclinic.com/health/prostate-cancer/HQ01273/>

Summary: 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.

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-threat
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.
ening can make decision making complicated.
The number of deaths from prostate cancer has gone down since PSA testing became available.

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.

What's risky about a PSA test?

You may wonder how getting a test for prostate cancer could have a downside. After all, there's little risk involved in the test itself — it requires simply drawing blood for evaluation in a lab. However, there are some potential dangers once the results are in. These include:

  • Worry about false-positive results caused by elevated PSA levels from something other than prostate cancer
  • Invasive, stressful, expensive or time-consuming follow-up tests
  • False reassurance from a PSA test that doesn't reveal cancer (false-negative), leading to a missed diagnosis of aggressive prostate cancer that needs treatment
  • Stress or anxiety caused by knowing you have a slow-growing prostate cancer that doesn't need treatment
  • Deciding to have surgery, radiation or other treatments that cause side effects that are more harmful than untreated cancer

Digital rectal examination

The PSA test isn't the only screening tool for prostate cancer. Digital rectal examination (DRE) is another important way to evaluate the prostate and look for signs of cancer. Your doctor performs the test by inserting a gloved, lubricated finger into your rectum to feel the prostate for bumps or other abnormalities. It's a quick, safe and easy test.

In addition to checking for signs of prostate cancer, your doctor can use a DRE to check for signs of rectal cancer. A DRE should always be done with a PSA test when screening for prostate cancer. This will help minimize the risk of missing prostate cancer — or wrongly identifying a benign prostate abnormality as cancer.

Think about your risk factors for prostate cancer

Knowing the risk factors for prostate cancer can help you determine if and when you want to begin prostate cancer screening. The main risk factors include:

  • Age. As you get older, your risk of prostate cancer increases. After age 50, your chance of having prostate cancer increases substantially. The majority of prostate cancers are found in men age 65 or older. The option to have PSA testing begins at age 40 and continues until you're at the age when your life expectancy is 10 years or fewer. Once you reach that age, the likelihood that a prostate cancer would progress and cause problems during the remainder of your lifetime is small.
  • Race. For reasons that aren't well understood, black men have a higher risk of developing and dying of prostate cancer.
  • Family history. If a close family member — your father or brother — was diagnosed with prostate cancer before age 65, your risk of the disease is greater than that of the average American man. If several of your first-degree relatives — father, brothers, sons — have had prostate cancer at an early age, your risk is considered very high.
  • Diet. A high-fat diet and obesity may increase your risk of prostate cancer.

Consider the varying viewpoints: What are the recommendations?

Organization Recommendation
American Urological Association (AUA) The AUA recommends that doctors offer a baseline PSA test to men who wish to be screened at age 40. It also encourages men who expect to live at least another 10 years to discuss the risks and benefits of PSA testing with their doctors.
American Cancer Society (ACS) The ACS recommends that men consult with their doctors to make a decision about PSA testing. According to the ACS, men should explore the risks and benefits of the PSA test starting at age 50 if they are at average risk of prostate cancer, at age 45 if they are at high risk and at age 40 if they are at very high risk (those with several first-degree relatives who had prostate cancer at an early age).
Centers for Disease Control and Prevention (CDC) The CDC recommends against PSA-based screening for men who do not have symptoms, but supports discussions between men and their doctors to make informed decisions about screening based on individual risks and preferences.
U.S. Preventive Services Task Force (USPSTF) The USPSTF recommends against PSA-based screening, regardless of age. The USPSTF states that there is moderate to high certainty that PSA testing has no net benefit or that harms outweigh benefits.
American College of Preventive Medicine (ACPM) The ACPM recommends that a man decide about whether to have PSA testing after discussing the risks and benefits with his doctor. The ACPM considers the need for screening questionable in older men with other chronic illnesses and men with life expectancies of fewer than 10 years.
Institute for Clinical Systems Improvement (ICSI) The ICSI states that, while there is good evidence that PSA screening can detect early-stage prostate cancer, there is mixed or inconclusive evidence to clearly determine whether early detection improves health outcomes. It recommends that a man decide what's right for him based on talking with his doctor.
Mayo Clinic Mayo Clinic recommends offering PSA screening and DRE annually to men ages 50 to 75 with a life expectancy greater than 10 years, to African-American men ages 45 to 75 with a life expectancy greater than 10 years, and to men ages 45 to 75 years with a positive family history of prostate cancer and a life expectancy greater than 10 years.

How does it add up?

A positive PSA test can be a lifesaver for some men, identifying prostate cancer that needs treatment early. It's generally a good idea to have PSA testing done if you're at increased risk of prostate cancer. However, not all men need to have the screening. You may want to think twice if you're in a group of men unlikely to benefit from it. After considering the pros and cons of screening, your age, general health and risk factors, your preferences and what the experts say, talk to your doctor. Together you can make the right decision for you.

Copyright © 1998-2012 Mayo Foundation for Medical Education and Research

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