Prostate-specific antigen (PSA) test

Prostate-specific antigen (PSA) is a protein produced by the prostate gland. Blood PSA levels can be elevated in prostate cancer as well as a number of other conditions including benign prostatic hypertrophy, prostatitis and urinary tract infection. The PSA test is the most commonly used test that can lead to the diagnosis of localised prostate cancer for which potentially curative treatment can be offered. Increased PSA levels may be associated with a raised probability of prostate cancer. However, many men have raised PSA levels without having prostate cancer and many men with prostate cancer don’t have raised PSA levels.

Typically, those with persistently raised PSA levels are referred on for further evaluation and may be offered histological assessment by trans-rectal or trans-perineal biopsy. Some centres are now using multi-parametric MRI scans to further assess people before taking biopsies. MRI is less likely than biopsy to detect clinically insignificant cancers and therefore reduces over-diagnosis. MRI also enables a more accurate diagnosis of clinically significant cancers because the MRI image can be used to target the biopsy.

Biopsies help to confirm the presence of cancer and allows an assessment of the cancer grade and stage. It is possible that biopsies not guided by MRI imaging can miss smaller areas of cancer or detect indolent disease of unclear clinical significance (which may subsequently require further investigation or treatment). There are a number of potential adverse effects of biopsies including pain, bleeding, urinary retention, infection (which may become serious sepsis) and sexual problems. It is also recognised this process has a significant psychological burden.

This guidance applies to male adults aged 19 years and over.

Where PSA testing is clinically indicated (see below), or requested by the man aged 50 and over, he should have a careful discussion about the potential risks and benefits of PSA testing which allows for shared decision making before a PSA test. Various tools are available to assist with shared decision making (see below).

PSA testing should be considered in asymptomatic men over age 40 who are at higher risk of prostate cancer due if they are Black and/or have a family history of prostate cancer. PSA testing should be considered when clinically indicated (ideally after counselling on the potential risks and benefits of testing) in men when there is clinical suspicion of prostate cancer, which may include the following symptoms:

• Lower urinary tract symptoms (LUTS), such nocturia, urinary frequency, hesitancy, reduced flow, urgency or retention.
• Erectile dysfunction.
• Visible haematuria.
• Unexplained symptoms that could be due to advanced prostate cancer (for example lower back pain, bone pain, weight loss).

PSA testing for prostate cancer is not recommended in asymptomatic men (unless they are at high risk of prostate cancer i.e. Black and/or family history). This is because the benefits have not been shown to clearly outweigh the harms. In particular, there is concern about the high risk of false positive results. Where PSA test results are mildly raised above the age specific range for an individual patient, it may be appropriate to repeat the test within two to three months to monitor the trend.

Note: PSA testing for prostate cancer should be avoided if the patient has:

• An active or recent urinary infection (PSA may remain raised for many months).
• Had a prostate biopsy in the previous 6 weeks, 

Both of which are likely to raise PSA and give a false positive result.

Relevant Resources for shared decision making

Public Health England (PHE) patient information sheet. PSA testing and prostate cancer: advice for well men aged 50 and over.

Prostate Cancer Research Foundation – SWOP Risk Calculator.

Choosing Wisely UK. Patient education and shared decision-making resources (download below).

Prostate Cancer UK. Patient education and shared decision-making resources.

PSA testing for prostate cancer in asymptomatic men remains controversial. Testing probably increases the diagnosis of prostate cancer but there is little or no evidence this has an effect on cancer related mortality. Testing is also known to be associated with potential harms including overdiagnosis, infection and complications of treatment for indolent disease. Evidence suggests that people at high risker of prostate cancer may benefit more from PSA testing.

Recently published UK guidance, based on an updated systematic review, made a weak recommendation against offering systematic PSA testing. This was because of the small and uncertain benefits of testing on prostate cancer mortality and the large variability in men’s values and preferences. Given the lack of clear benefits, the group highlighted the importance of shared decision making in deciding whether to proceed with PSA testing which, is supported by other evidence.

It is worth considering that the USA Preventive Services Task Force (USPSTF) has previously recommended against prostate cancer screening using PSA testing in men aged 75 years and above. The European Randomised study of Screening for Prostate Cancer (ERSPC) suggests that screening may reduce the long term risk of prostate cancer-specific mortality by at least 9% (relative reduction).

NICE guidance stresses the importance of considering symptoms when proposing a PSA test and offering PSA to symptomatic men with lower urinary tract symptoms (LUTS), such as nocturia, urinary frequency, hesitancy, urgency or retention, erectile dysfunction, visible haematuria, or symptoms that could be due to advanced prostate cancer (for example lower back pain, bone pain, weight loss). It also advises on the use of tools to aid shared decision making between clinician and patient when deciding on PSA testing.

Information for Patients

Prostate specific antigen (PSA) testing is only recommended for people with a prostate who have symptoms of prostate cancer. There are possible harms from the investigations that may follow a PSA test. Medical evidence tells us these possible harms are greater than the possible benefits of doing the test for people who do not have symptoms of prostate cancer.

About the condition

A PSA test is a blood test that looks for a raised PSA level. PSA is a protein produced by the prostate gland. It may increase in people with prostate cancer. But it may also increase in conditions which are not serious, such as urinary tract infections.

What are the BENEFITS of the test?

A raised PSA level may indicate prostate cancer. This raised PSA may therefore lead to further investigations such as an MRI scan or biopsy that can tell you whether you have cancer or not. If you do have prostate cancer you can then be referred for treatment.

What are the RISKS?

There are many reasons why PSA levels may be raised which are not related to cancer. Being told you have a raised PSA after a PSA test may cause unnecessary concern. A raised PSA level could lead to unnecessary further tests, including a biopsy. Biopsies carry their own risks.

What are the ALTERNATIVES?

There is currently no reliable alternative blood test that can indicate prostate cancer. You should talk to your doctor if you have symptoms that may indicate prostate cancer. These symptoms may include blood in your urine (pee), urgency to pass urine, reduced flow of urine, unable to pass urine, needing to pass urine at night frequently, erectile dysfunction (unable to keep an erection), weight loss, lower back pain that won’t go away and bone pain. Your doctor will then help you decide if a PSA test is needed.

What if you do NOTHING?

If you have no symptoms of prostate cancer, you are unlikely to come to harm by not having the PSA test.

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10. NICE Clinical Knowledge Summary Prostate Cancer
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November 2020