Screening is testing to find cancer in people before they have symptoms. It’s not clear, however, if the benefits of prostate cancer screening outweigh the risks for most men. Still, after discussing the pros and cons of screening with their doctors, some men might reasonably choose to be screened.
The screening tests discussed here are used to look for possible signs of prostate cancer. But these tests can’t tell for sure if you have cancer. If the result of one of these tests is abnormal, you will probably need a prostate biopsy (discussed below) to know for sure if you have cancer.
Prostate-specific antigen (PSA) is a protein made by cells in the prostate gland (both normal cells and cancer cells). PSA is mostly found in semen, but a small amount is also found in blood.
The PSA level in blood is measured in units called nanograms per milliliter (ng/mL). The chance of having prostate cancer goes up as the PSA level goes up, but there is no set cutoff point that can tell for sure if a man does or doesn’t have prostate cancer. Many doctors use a PSA cutoff point of 4 ng/mL or higher when deciding if a man might need further testing, while others might recommend it starting at a lower level, such as 2.5 or 3.
If your PSA level is high, you might need further tests to look for prostate cancer (see ‘If screening test results aren’t normal’, below).
One reason it’s hard to use a set cutoff point with the PSA test when looking for prostate cancer is that a number of factors other than cancer can also affect PSA levels.
Factors that might raise PSA levels include:
Some things might lower PSA levels (even if a man has prostate cancer):
For men who might be screened for prostate cancer, it’s not always clear if lowering the PSA is helpful. In some cases the factor that lowers the PSA may also lower a man’s risk of prostate cancer. But in other cases, it might lower the PSA level without affecting a man’s risk of cancer. This could actually be harmful, if it were to lower the PSA from an abnormal level to a normal one, as it might result in not detecting a cancer. This is why it’s important to talk to your doctor about anything that might affect your PSA level.
The PSA level from a screening test is sometimes referred to as total PSA, because it includes the different forms of PSA (described below). If you decide to get a PSA screening test and the result isn’t normal, some doctors might consider using different types of PSA tests to help decide if you need a prostate biopsy, although not all doctors agree on how to use these tests. If your PSA test result isn’t normal, ask your doctor to discuss your cancer risk and your need for further tests.
Percent-free PSA: PSA occurs in 2 major forms in the blood. One form is attached to blood proteins, while the other circulates free (unattached). The percent-free PSA (%fPSA) is the ratio of how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not.
If your PSA test result is in the borderline range (between 4 and 10), the percent-free PSA might be used to help decide if you should have a prostate biopsy. A lower percent-free PSA means that your chance of having prostate cancer is higher and you should probably have a biopsy.
Many doctors recommend a prostate biopsy for men whose percent-free PSA is 10% or less, and advise that men consider a biopsy if it is between 10% and 25%. Using these cutoffs detects most cancers and helps some men avoid unnecessary biopsies. This test is widely used, but not all doctors agree that 25% is the best cutoff point to decide on a biopsy, and the cutoff may change depending on the overall PSA level.
Complexed PSA: This test directly measures the amount of PSA that is attached to other proteins (the portion of PSA that is not “free”). This test could be done instead of checking the total and free PSA, and it could give the same amount of information, but it is not widely used.
Tests that combine different types of PSA: Some newer tests combine the results of different types of PSA to get an overall score that reflects the chance a man has prostate cancer (particularly cancer that might need treatment).These tests include:
These tests might be useful in men with a slightly elevated PSA, to help determine if they should have a prostate biopsy. These tests might also be used to help determine if a man who has already had a prostate biopsy that didn’t find cancer should have another biopsy.
PSA velocity: The PSA velocity is not a separate test. It is a measure of how fast the PSA rises over time. Normally, PSA levels go up slowly with age. Some research has found that these levels go up faster if a man has cancer, but studies have not shown that the PSA velocity is more helpful than the PSA level itself in finding prostate cancer. For this reason, the ACS guidelines do not recommend using the PSA velocity as part of screening for prostate cancer.
PSA density: PSA levels are higher in men with larger prostate glands. The PSA density (PSAD) is sometimes used for men with large prostate glands to try to adjust for this. The doctor measures the volume (size) of the prostate gland with transrectal ultrasound (discussed in Tests to Diagnose and Stage Prostate Cancer) and divides the PSA number by the prostate volume. A higher PSA density indicates a greater likelihood of cancer. PSA density has not been shown to be as useful as the percent-free PSA test.
Age-specific PSA ranges: PSA levels are normally higher in older men than in younger men, even when there is no cancer. A PSA result within the borderline range might be worrisome in a 50-year-old man but cause less concern in an 80-year-old man. For this reason, some doctors have suggested comparing PSA results with results from other men of the same age.
But the usefulness of age-specific PSA ranges is not well proven, so most doctors and professional organizations (as well as the makers of the PSA tests) do not recommend their use at this time.
For a digital rectal exam (DRE), the doctor inserts a gloved, lubricated finger into the rectum to feel for any bumps or hard areas on the prostate that might be cancer. As shown in the picture below, the prostate is just in front of the rectum. Prostate cancers often begin in the back part of the gland, and can sometimes be felt during a rectal exam. This exam can be uncomfortable (especially for men who have hemorrhoids), but it usually isn’t painful and only takes a short time.
DRE is less effective than the PSA blood test in finding prostate cancer, but it can sometimes find cancers in men with normal PSA levels. For this reason, it might be included as a part of prostate cancer screening.
If you are screened for prostate cancer and your initial blood PSA level is higher than normal, it doesn’t always mean that you have prostate cancer. Many men with higher than normal PSA levels do not have cancer. Still, further testing will be needed to help find out what is going on. Your doctor may advise one of these options:
It’s important to discuss your options, including their possible pros and cons, with your doctor to help you choose one you are comfortable with. Factors that might affect which option is best for you include:
If your initial PSA test was ordered by your primary care provider, you may be referred to a urologist (a doctor who treats cancers of the genital and urinary tract, which includes the prostate gland) for this discussion or for further testing.
A man’s blood PSA level can vary over time (for a number of reasons), so some doctors recommend repeating the test after a month or so if the initial PSA result is abnormal. This is most likely to be a reasonable option if the PSA level is on the lower end of the borderline range (typically 4 to 7 ng/mL). For higher PSA levels, doctors are more likely to recommend getting other tests, or going straight to a prostate biopsy.
If the initial PSA result is abnormal, another option might be to get another type of test (or tests) to help you and your doctor get a better idea if you might have prostate cancer (and therefore need a biopsy). Some of the tests that might be done include:
(If the initial abnormal test was a DRE, the next step is typically to get a PSA blood test (and possibly other tests, such as a TRUS).)
For some men, getting a prostate biopsy might be the best option, especially if the initial PSA level is high. A biopsy is a procedure in which small samples of the prostate are removed and then looked at under a microscope. This test is the only way to know for sure if a man has prostate cancer. If prostate cancer is found on a biopsy, this test can also help tell how likely it is that the cancer will grow and spread quickly.
For more details on the prostate biopsy and how it is done, see Tests to Diagnose and Stage Prostate Cancer.
For more information about the possible results of a prostate biopsy, see the Prostate Pathology section of our website.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
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Last Revised: January 4, 2021
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