The Pros and Cons of the PSA Test

Date: 29 March 2018

More than 40,000 men in England were diagnosed with prostate cancer in 2015, and more than 10,000 men died from it.

In Yorkshire alone, 3,600 men were diagnosed, while nearly 1,000 men died1.

It is the second most common cancer in England, and the third most common cause of cancer-related death2.

If a man is diagnosed with cancer at the earliest possible stage, they have an extremely high chance of survival as prostate cancers diagnosed at an early stage (stage 1 and 2) are highly treatable.

We know that one way to get more people diagnosed early is by taking part in national screening programmes. So why isn’t there a national screening programme for prostate cancer?

PSA blog post

The current national screening programmes

In England, there are national screening programmes for bowel, breast and cervical cancer.

These screening programmes are important tools for detecting cancer at an early stage, or finding abnormal cells before they have the chance to develop into cancer.

Nearly 3 in 10 breast cancer cases in England are diagnosed through screening, and around half of all stage 1 breast cancers are diagnosed through the programme2. Breast cancer screening has been shown to reduce the number of deaths from breast cancer by about 1,300 a year in the UK3.

About 2 in 10 cervical cancer cases in England are diagnosed through screening2. Cervical screening has been shown to save 5,000 lives in the UK every year4. The most important benefit of cervical screening is that it can detect abnormal cells, and if necessary, these can be removed before they become cancer.

Participation in bowel cancer screening is lower with fewer than 1 in 10 bowel cancers diagnosed through screening. However, those diagnosed through screening have a 93% chance of surviving for at least three years after diagnosis, compared to 68% if they are referred to hospital through their GP2. With regular screening, 16% fewer people die from bowel cancer5.

All these programmes have been proven to be effective in reducing the number of deaths from cancer, and we strongly recommend that people who are eligible take part when invited.

For prostate cancer, an equivalent screening programme has not been developed. Men with possible prostate cancer symptoms will often be asked to complete a PSA test when they visit their doctor.

What is the PSA test?

The PSA test is a blood test that measure the levels of a protein called ‘prostate-specific antigen’ (PSA).

PSA is made in the prostate gland, and some will leak into the blood. If the blood test shows that the PSA level in the blood is high, then further tests may be needed, such as a biopsy. A biopsy involves taking small samples of the prostate and checking them for cancer.

A raised PSA level may indicate prostate cancer, however it can be high for other reasons. These include:

  • Enlarged prostate
  • Urinary infection
  • Recent vigorous exercise
  • Recent ejaculation
  • Some medications
  • Other tests, such as a prostate biopsy, can also increase your PSA level

If you are over 50 you can request a PSA test at your local GP surgery, even if you don’t have any symptoms.

Why isn’t the test offered more widely?

While the introduction of the PSA test has resulted in an increase in the number of men diagnosed with prostate cancer, it has had no effect on the number of men who die from the disease.

This means that many men are diagnosed with a cancer that may have never caused symptoms and therefore would never have needed treatment. This is called overdiagnosis.

Many prostate cancers don’t cause problems for men during their lifetime because they are very slow-growing.

Overdiagnosis can lead to unnecessary worry and anxiety as well as side effects related to the treatment of cancer.

Treatment options include surgery, radiotherapy and hormone therapy, and side effects of these treatments such as incontinence and erectile dysfunction6 can have a significant impact on everyday life.

The pros and cons7

If you are worried about prostate cancer, it’s important that you understand the advantages and disadvantages of the PSA test. Have a conversation with your doctor before making a decision.

Advantages

  • It may reassure you if the test result is normal.
  • It can catch prostate cancer early, before symptoms develop, which means earlier treatment and the possibility of a better outcome.
  • Around 30% more men are diagnosed with prostate cancer when screening is used.

Disadvantages

  • The test isn’t 100% accurate so you may get a negative result when you do actually have prostate cancer (known as a false negative). About 15 out of every 100 men who have a normal PSA test result do have prostate cancer.
  • The PSA test can’t tell the difference between fast-growing cancers (which will need treatment) and slow-growing cancers, which may have never caused symptoms or shortened your life (therefore causing unnecessary treatment). Unnecessary treatment can cause worry and side effects such as infection, bleeding, pain, incontinence, erectile dysfunction and pneumonia.
  • An abnormal result does not mean you have prostate cancer (false positive). Your PSA level can be raised for a number of reasons, including a urinary infection. About 75 out of every 100 men who have an abnormal PSA test result do not have prostate cancer.
  • Evidence suggests that the PSA test has no significant effect on mortality rates.

The future

Before a national screening programme for prostate cancer can be introduced, a more reliable test must be found. More research is needed to find a way of diagnosing prostate cancers that are likely to cause harm, so that we only treat men whose lives are at risk.

In the meantime, it’s vital that we continue to raise awareness of prostate cancer signs and symptoms so that even if there isn’t a screening programme, we can try to increase the number of men diagnosed at the earliest possible stage.

Prostate cancer symptoms include:

  • needing to urinate more frequently, often during the night
  • needing to rush to the toilet
  • difficulty in starting to pee (hesitancy)
  • straining or taking a long time while urinating
  • weak flow
  • feeling that your bladder has not emptied fully8

If you notice any unusual changes to your body, please talk to your doctor.


 

References

1. https://www.cancerdata.nhs.uk/
2. http://www.ncin.org.uk/publications/routes_to_diagnosis
3. http://www.cancerresearchuk.org/about-cancer/breast-cancer/screening/breast-screening
4. Peto et al., 2004. The cervical cancer epidemic that screening has prevented in the UK. Lancet 35, 249–256.
5. https://www.macmillan.org.uk/information-and-support/diagnosing/how-cancers-are-diagnosed/bowel-screening/benefits-disadvantages.html
6. https://www.nhs.uk/Livewell/Prostatehealth/Pages/psa-test.aspx
7. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/509191/Patient_info_sheet.pdf
8. https://www.nhs.uk/conditions/prostate-cancer/symptoms/

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