Prostate cancer is the abnormal growth of cells in the tissues of the prostate gland . It is the most common cancer in men. Most men who get it are older than 65.

Unlike many other cancers, it is usually slow-growing. For most men, this slow growth means they have time to learn all they can before deciding whether to have treatment or which treatment to have.

Early prostate cancer usually doesn't cause symptoms. When prostate cancer is found early, before it has spread outside the prostate gland, it may be cured with radiation or surgery to remove the prostate. As prostate cancer grows or spreads, symptoms may develop, including urinary problems (such as blood in the urine) and bone pain.

The prostate-specific antigen (PSA) test is a blood test. PSA is released into a man's blood by the cells of his prostate gland. Low amounts of PSA may be found in the blood of healthy men. The amount of PSA in the blood normally increases as a man's prostate enlarges with age. And it increases after ejaculation and after trauma to the prostate caused by such things as a long bike ride. It is also increased by inflammation of the prostate gland (prostatitis) and by prostate cancer.

The PSA test is usually done along with a digital rectal exam to screen for prostate cancer in men who have no symptoms. A PSA test may also be used to check men who have had prostate cancer to see if the cancer has come back.

A high PSA result can be the first warning sign of prostate cancer. A high PSA can signal a higher risk of getting prostate cancer in the future. But a high PSA can also be linked to other causes that aren't cancer.

The amount of PSA in the blood normally increases as a man's prostate enlarges with age. But when you have prostate cancer, your PSA level increases even more over time.

The PSA test and digital rectal exam can suggest a problem when there is not one. This is called a false-positive result.

These tests may also fail to detect a problem when there is one. This is called a false-negative result.

A PSA test alone can't tell if you have prostate cancer. This test only shows the level of your PSA. And a PSA test can't tell why your level is high.

The prostate naturally gets bigger as a man gets older. More than half of all men who are older than 50 have an enlarged prostate. This affects the PSA level, making it less accurate as a way to detect cancer.

Because several other things can make a PSA level go up—for example, ejaculation or an infection in the prostate—your doctor may advise you to have another PSA test later before you make any further decisions.

If your PSA test suggests that you may have prostate cancer, your doctor may recommend a biopsy, which is the only way to make sure that you have prostate cancer. If the biopsy finds cancer, you must decide how or whether to treat it.

A few prostate cancers grow fast. Men who have fast-growing cancers are more likely to die from prostate cancer than men who have slower-growing cancers. But PSA tests may not help men who have fast-growing cancers that have spread quickly. And doctors can't tell which kinds of slow-growing cancers will cause problems. Treatments can have serious long-term side effects. They may cause health problems, including problems with your bladder, bowel, and erections. For this reason, some men choose not to have the PSA test.

In men who have not been diagnosed with prostate cancer, PSA velocity can show that there is a problem that needs further testing. PSA velocity is measured by looking at the rate of change in PSA levels over 2 or 3 years. PSA levels rise faster in men who have prostate cancer than they do in men who have enlarged prostates.

*Based on the best available evidence (evidence quality: borderline to moderate)

Benefits

The quality of the evidence about PSA benefits is borderline.

It's easy to assume that cancer screening tests save lives. And some do. But in the case of prostate cancer screening, PSA testing has not been shown to reduce a man's risk of dying in the next 10 years.

Take a group of 100 men, ages 45 to 80 . Whether they have PSA tests or not, 7 to 8 out of 100 may die of prostate cancer in the next 10 years, which means that 92 to 93 out of 100 may not. Their risk of death from prostate cancer is the same with or without PSA tests.

One benefit may be that cancer is more likely to be found with PSA testing than without. Take a group of 100 men :

• If all of them have PSA tests, testing may find 6 to 7 cancers.
• If none of them have PSA tests, 4 to 5 cancers may be found.

But this can be a mixed blessing. Some prostate cancers that are found may never have caused a problem or needed treatment had they not been found.

Risks

The quality of the evidence about PSA risks is moderate.

One risk of PSA tests is that they can suggest a problem when there isn't one. This is called a false-positive result. It can lead to more invasive testing.

Take a group of 100 men who have a positive PSA test . Only 17 to 24 of these men actually have prostate cancer. This means that 76 to 83 of them do not have prostate cancer, even though their PSA results are positive.

If your PSA test is positive, your doctor may recommend a biopsy, which is the only way to make sure you have prostate cancer.

Biopsy has its own risks. Take a group of 100 men who have a prostate biopsy . Less than 1 out of 100 will have a problem from the procedure, such as infection, bleeding, a blood clot, or problems urinating. (Out of 1,000 men who have a biopsy, 1 to 7 will have a problem from the procedure. This means that 993 to 999 out of 1,000 will not have any problem.)

Understanding the evidence

Some evidence is better than other evidence. Evidence comes from studies that look at how well treatments and tests work and how safe they are. For many reasons, some studies are more reliable than others. The better the evidence is—the higher its quality—the more we can trust it.

The information shown here is based on the best available evidence.^{1, 2, 3, 4, 5, 6, 7} The evidence is rated using four quality levels: high, moderate, borderline, and inconclusive.

Another thing to understand is that the evidence can't predict what's going to happen in your case. When evidence tells us that 2 out of 100 people who have a certain test or treatment may have a certain result and that 98 out of 100 may not, there's no way to know if you will be one of the 2 or one of the 98.

Your chance of getting prostate cancer increases as you age. Men who are younger than 75 and who do not have serious health problems may gain the most from early detection and treatment.

Most medical experts say that men age 50 or older should talk to their doctors about the pros and cons of PSA testing so that they can make their own decisions.

Some experts worry that PSA testing for prostate cancer begins a process that can force a man to make hard decisions and can lead to other health problems that are caused by the treatment for prostate cancer. Here's what some experts say:

• The U.S. Preventive Services Task Force (USPSTF) recommends against routine PSA tests to look for prostate cancer. The USPSTF found that testing does more harm than good. Men who are tested may end up getting treatment they don't need, and those treatments can cause other problems. Few, if any, men are helped to live longer by having the test.
• The American Cancer Society (ACS) advises men to talk with their doctors about testing and treatment before deciding about testing. The ACS says that men should not be tested without learning about the risks and benefits. The ACS advises talking to a doctor about testing:
  • At age 50 for men who are at average risk of getting prostate cancer and are expected to live at least 10 more years.
  • At age 45 for men at high risk, such as African Americans and men who have a first-degree relative (father, brother, or son) who had prostate cancer when he was younger than 65.
  • At age 40 for men at an even higher risk, such as those with several first-degree relatives who had prostate cancer at an early age.
• The American Urological Association (AUA) recommends that men decide with their doctors about screening. If a man decides to be screened, the AUA says he should start at the age of 40 for a "baseline" score (a baseline score is a PSA level that can be used to compare with future test scores).

Your doctor may recommend a PSA test if he or she thinks you may have prostate cancer.

Your doctor may discuss PSA screening if:

• You are in your 50s or 60s and are in good health.
• Your doctor wants to keep track of changes in your PSA level.
• You are an African American or a Jamaican of African descent, which means that you have a greater chance of getting the kind of prostate cancer that grows and spreads.
• Your father, brother, or son got prostate cancer before age 65.