Screening for prostate cancer using the prostate specific antigen (PSA) blood test remains controversial, but new evidence has emerged in recent years which may help when faced with this potentially difficult consultation. There is a huge amount of media interest in prostate cancer, fuelled by a number of high profile celebrities who have publicised their diagnosis and treatment and encouraged men to come forward to ask for PSA testing.
How should he be assessed?
When a man requests a PSA test the first thing you should do is find out why. This patient’s reason is one of the three most common:
- ‘I have read about testing for prostate cancer in the newspapers and would like to be given a test’ – this is often an asymptomatic patient.
- ‘I have a weak bladder and would like to make sure it is nothing serious’ – i.e. some form of lower urinary tract symptoms have precipitated the request.
- ‘My dad/brother has been diagnosed with prostate cancer so I would like to make sure I don’t have it as well’
This patient is 40-years-old and mentions that prostate cancer is in his family and it is important to ascertain what he means by this.
Firstly, ensure that he really does mean prostate cancer and not urinary symptoms or treatment for LUTS due to benign enlargement of the prostate – these are often confused.
Secondly, find which relatives have been diagnosed and at what age – a man with a father diagnosed over the age of 60 has a 12% lifetime risk of prostate cancer, compared to an 8% risk in a man with no family history. If three or more relatives have been affected, his risk is approximately 35-45%.1 Also remember that if he is of African-Caribbean background this will further significantly increase his risk of developing prostate cancer.
He may have symptoms that have precipitated this request for PSA testing, and given his age, if this is the case, they are extremely unlikely to be due to prostate cancer. It may be helpful to explain this as most men with LUTS are worried about the possibility of prostate cancer.
If he has LUTS, try to ascertain if they are storage symptoms, voiding symptoms or a combination of both (see box 1). In a younger man with voiding LUTS, think of conditions such as urethral stricture or bladder neck dysfunction. If storage symptoms predominate, think of overactive bladder.
Urgency +/- Urgency Incontinence
In assessing any man with LUTS, the NICE LUTS guideline suggests that a focused abdominal examination, examination of external genitalia and digital rectal examination should be performed.2
Urine should be dipped and the patient should be asked to complete a frequency volume chart to assess his symptoms. However, if he is asymptomatic most of this assessment is unnecessary other than to consider carrying out a DRE to assess prostate size and consistency.
There is no good evidence to say this is mandatory, but adding a DRE alongside a PSA may improve your ability to interpret any subsequent PSA test ie a large prostate with a borderline PSA would be less worrying than if the prostate felt small on examination.
What are the pros and cons of PSA testing?
Benefits of testing
- Your patient may feel reassured that his PSA is normal and therefore that he is at low risk of prostate cancer
- PSA may be of use as a surrogate marker of prostate volume in men with benign prostatic enlargement and as a predictor of those most likely to have progressive LUTS or acute urinary retention.
- A large European screening study showed a decrease in prostate cancer mortality (but not all cause mortality) in men screened with PSA testing every four years – however, to save one life from prostate cancer, over 1400 men needed to be screened and 48 men treated, suggesting a significant problem with over-diagnosis and over-treatment.
Harms of testing
A recent position statement from the US Preventive Services Task Force (USPSTF) on PSA screening lists the potential harms of screening outlined that for every 1,000 men who are screened with the PSA test:3
- 30-40 men will develop erectile dysfunction or urinary incontinence due to treatment
- two men will experience a serious cardiovascular event, such as a heart attack, due to treatment
- one man will develop a serious blood clot in his leg or lungs due to treatment
For every 3,000 men who are screened with the PSA test:
- one man will die due to complications from surgical treatment
Current guidance on who should be tested and when?
Both the USPSTF and the UK National Screening Committee have recommended against screening for prostate cancer using PSA due to the small benefits and what they believe to be a significant risk of harm.
In the UK, primary care clinicians are guided by the Prostate Cancer Risk Management Programme.4 This states that ‘all men over the age of 50 should be allowed a PSA test as long as they have made an informed choice as to the risks and benefits associated’, but this guidance does not help the GP in cases where the patient is under 50.
What is the significance of his young age?
There is increasing interest in the use of a baseline PSA test, taken at a relatively young age (between 40 and 45 years). At this age PSA results are far less affected by background benign prostatic enlargement, and a number of studies have shown that over long-term follow-up, the PSA level at this young age can not only stratify men into low and high risk groups for subsequent development of prostate cancer but also predict the risk of future metastasis and death from the disease.
As a result, the European Association of Urology (EAU) has recently recommended that all men are offered a baseline PSA test between the ages of 40 and 45.5 A recent consensus statement by urologists at the Prostate Cancer World Congress has also recommended this approach as an evidence-based strategy for risk stratification in younger men.6
What are the possible outcomes of the test and when should it be repeated?
If a man aged 40 has a PSA test, the result is likely to be normal i.e. within the age-specific accepted range. But the evidence on baseline testing suggests that even within these so called normal results, risk of future prostate cancer can be reliably predicted.
The EAU suggest that if his PSA is <1.0 ng/ml at this age, he can be reassured that not only is his current risk extremely low, but so is future risk, and repeat testing may not be necessary for 8-10 years depending on the strength of his family history. Clearly a shorter interval would be wise in the presence of a strong family history.
If his PSA was >1.0 ng/ml he falls into the higher risk category, and repeat testing may be sensible at a 2-4 year interval. If his PSA is raised above age-specific normal values, discussion with a urologist or referral is likely to be needed.
- Failure to account for family history or racial background could lead to false underestimation of prostate cancer risk, and presentation of an overly negative view of the benefit of a PSA test to this patient.
- Lack of awareness of the significance of baseline PSA at a young age in predicting future prostate cancer risk could lead to false reassurance.
Dr Jonathan Rees is a men’s health and urology GPSI in Bristol.
Alex Edgerley is a 4th year medical student at the University of Bristol
- Madersbacher S, Alcaraz A, Emberton M et al. The influence of family history on prostate cancer risk: implications for clinical management. BJU International, 2010; 107: 716–721
- NICE. CG97: The management of lower urinary tract symptoms in men. May 2010
- Moyer VA. Screening for prostate cancer: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine, 2012; 157 (2): 1-16
- Prostate Cancer Risk Management Programme
- Heidenreich A, Abrahamsson PA, Artibani W et al. Early detection of prostate Ccncer: European Association of Urology recommendation. European Urology, 2013; 64 (3): 347-354
- The Melbourne consensus statement on prostate cancer testing
Prosdex – online patient decision aid re PSA testing: