The PSA test for prostate cancer – everything you need to know

Telegraph

2 days ago

Prostate cancer is the most common form of cancer among men in England, with cases surging among both men and women by 25 per cent between 2019 and 2023 according to NHS data. It's also the second deadliest form of the disease for men after lung cancer, killing one man every 45 minutes despite being highly curable if caught in time.
Yet there is still no formal screening programme for prostate cancer in the UK. In the US, Czech Republic and Lithuania by contrast, screening is offered to men within a certain age bracket via a simple blood test, the PSA test.
'We know that in countries with formal PSA screening programs, the rates of advanced prostate cancer are a lot less,' says Prasanna Sooriakumaran, a professor of urology at the University of Oxford, and a consultant urologist at University College London Hospitals. 'In this country, one in five men with prostate cancer present at an advanced, incurable state whereas in the US, that number is significantly under 10 per cent and that's because of PSA screening.'
So what is this test and what does it tell you?
What is a PSA test?
As David James, the director of Prostate Cancer Research, explains, the PSA test measures the levels of a prostate-specific antigen, a protein made by cells within the prostate. Because cancerous cells can enable PSA to slip more easily out of the prostate and ultimately reach the bloodstream, it can serve as a biological signal for the presence of a tumour.
'High levels don't always mean cancer, but they can be an early warning sign and usually lead to further tests to find out if cancer is present,' says James. 'It's one of the best tools we have right now to help catch prostate cancer early, often before any symptoms appear.'
Who can have a PSA blood test?
While PSA testing is not routinely available on the NHS, all men aged 50 or over can, in theory, request an appointment with their GP to discuss the possibility of getting a test.
Black men over 45 who are at higher risk of prostate cancer because of their ethnicity are strongly recommended to discuss having a PSA test with a doctor, as well as all over-45s with a known family history of the disease.
Clément Orczyk, a consultant urological surgeon at University College London Hospitals says that PSA testing is also highly recommended for men who have blood in their urine, problems getting an erection or have begun peeing more than usual, although he urges men not to panic if they are having any of these symptoms. 'Most of the time it's linked to benign prostatic hyperplasia, the normal age-related enlargement of the prostate, not cancer,' he says.
What happens during the test?
Emma Craske, a specialist nurse for Prostate Cancer UK, explains that the PSA test is taken like any other blood test.
While some men are reluctant to come forward for testing because they are worried that it will lead to a digital rectal examination (DRE), she says this is unlikely to happen. Instead, an abnormal reading would lead to an MRI scan being booked at the hospital. 'The MRI scan is far more accurate at identifying abnormalities within the prostate than a DRE,' she says.
How do I request a PSA test?
Orczyk says that you simply have to book a GP appointment and request one. 'But before asking for a test, it's important to be prepared for the potential consequences of having the test,' he says. 'For example, the fact that you might then need to be referred for further screening, and because the test isn't necessarily specific to cancer, people can be sometimes falsely reassured or falsely alarmed by their results.'
Why would I be refused a test?
The most obvious reason is because you are not considered eligible, for example under 50 and with no standard risk factors. When such instances happen with men who should be eligible for a test, Sooriakumaran suggests that it may be because the GP is worried about their capability of interpreting a borderline result. 'If the result is grossly abnormal, it's easy for the GP, they send them on to a specialist, and if the result is normal, it's also easy for the GP,' he says. 'But it's that grey area which causes concern.'
What can I do if my GP refuses a PSA test?
There are an increasing number of high-street providers which offer low cost PSA tests, but Orczyk advises people to steer clear of them, as getting an accurate result requires the use of medically certified laboratories, such as those used by the NHS.
Instead, Sooriakumaran recommends pushing back, emphasising your concerns and explaining why you wish to have a test. 'I don't know many GPs these days that would point blank refuse if they were getting pushback,' he says. 'Tell them that specialists would much rather see men who got early curable prostate cancer, then men presenting much later with advanced cancer.'
Is there anything I can't do before the test?
According to Craske, anal sex and any form of prostate stimulation are out of bounds for a week before the test, while in the 48 hours prior to testing, men should also abstain from vigorous exercise and ejaculation. If you have recently had a urine infection, bladder or prostate surgery, she says it is advised to wait six weeks before having the test.
'You can eat and drink as normal before a PSA test, including alcohol,' says Craske. 'There are a group of medicines used to treat benign enlargement of the prostate that may artificially reduce the PSA level, known as 5-alpha-reductase inhibitors such as finasteride or dutasteride. Patients on these drugs need to have this taken into account when doctors interpret the results.'
How long will the results take?
Craske says that results usually come back within a week, and can be obtained either via the NHS App or by calling the surgery.
She advises asking for the exact figure, even if the result is normal. 'This can be helpful if you choose to have a PSA test in the future, to recognise a trend,' she says.
What is a high PSA and what does it mean?
Interpreting the PSA test can be complex, according to Sooriakumaran, as the results come with considerable individual variability. There are age-specific reference ranges for PSA because the prostate naturally enlarges and produces more of this protein as we get older. For example, if you are aged between 40-49, a PSA reading of more than 2.5ng/ml may be considered high, while if you are over 70, it would have to be more than 6.5 ng/ml.
But exceeding these thresholds does not automatically imply cancer. Craske explains that there can be other factors such as a recent urinary tract infection which elevate your PSA levels, while some men simply have a larger prostate than average, meaning that their 'normal' level is higher than others.
Because of this, statistics show that only one in four men that have a high PSA are at risk of having prostate cancer.
What is a normal PSA result?
Sooriakumaran says this would be a prostate-specific antigen reading which is within the expected range for your age group. So, for example, for men aged 50-59, this would be below 3.5ng/ml.
However again, a 'normal' value can differ from one man to another. 'What really matters is how the PSA changes with time,' says Sooriakumaran. 'Because there's no such thing really as a normal PSA or an abnormal PSA. It's all about how it is for your size of prostate.'
I have a normal PSA result. When should I check again?
Repeat testing tends to be recommended for men who have an increased risk of prostate cancer due to ethnicity or family history. Some healthcare providers, such as Johns Hopkins Medicine in the US, suggest getting PSA testing done every two to four years to see whether there is any change in the trend, but if your values are low and you have no known risk factors, the NHS may not offer repeat tests.
'If the PSA is completely bang normal, or in the low range, the PSA may not be repeated,' says Sooriakumaran. 'But if you have risk factors, it's up to the GP to decide whether they want to repeat the test one or potentially three years later.'
I have a high PSA result. What happens next?
If you have a family history of the disease, or you are of black or Ashkenazi Jewish ethnicity meaning that you are of heightened risk, or your PSA levels are particularly high, then your GP will have a discussion about referring you to a specialist for further testing.
While some urology specialists may suggest a rectal examination, Sooriakumaran says that more expert urologists will not because it is not a very sensitive or accurate test for prostate cancer. Instead the standard NHS pathway, as recommended by Nice guidelines following a high PSA reading, is a referral for an MRI of the prostate.
What further tests can I expect?
In some cases, a urine test may be offered to rule out infection as a possible cause of raised PSA levels. But the standard procedure is to then book an MRI of the prostate, followed by a prostate biopsy.
Biopsy technology has evolved considerably. Some NHS Trusts still carry out a transrectal prostate biopsy, where an ultrasound probe is inserted through the rectum and used to collect tissue samples from the prostate. However Sooriakumaran says that a newer technology, known as a transperineal biopsy – where a thin biopsy needle is inserted through the layer of perineal skin between the testicles and anus – is becoming more common as it is more accurate and carries a lower risk of infection. 'Over the next year or two, there will be fewer and fewer NHS Trusts that do a transrectal biopsy, and more will move to this newer method,' he says.
On the NHS, Sooriakumaran says that the standard timeframe for the results to become available is two to four weeks following the procedure. In the private sector, results will be available between three and seven days.
I have a high PSA result, but my GP won't refer me for further tests. What can I do?
This could be because while your PSA reading may be outside the expected range for your age, it is still considered only slightly abnormal. In such cases, Sooriakumaran says, it may be standard for a GP to repeat the result a few weeks later, before referring you for further testing.
If considered borderline, you may be offered a repeat PSA test six months or a year later, to help assess whether such a result is normal for you or not.
How accurate is the test?
While the PSA test plays an important role in ensuring that more men are put forward for detailed examinations, the test itself is not especially accurate.
According to Cancer Research UK, the major issue is so-called 'false positives' with 75 per cent of men with a high PSA value, not actually having prostate cancer. But there are also 'false negatives' with 15 per cent of men with a normal PSA value actually having the disease.
'This is where the value of the test is greatest when there's repeat measurement over time, so you can see if there's been a change,' says Sooriakumaran.
What other factors can raise your PSA levels?
As well as age and urinary tract infections, there are a range of factors which can increase your PSA levels in the short term, from inflammation of the prostate, or simply because you have recently been cycling or horse riding. In the latter case, the pressure and movement of the pelvic muscles against the prostate leads to increased blood flow and the release of more PSA into the bloodstream. Even ejaculating or having had sex during the past 48 hours can increase your PSA levels.
What are the downsides of the test?
One of the major risks is that men with a high PSA test reading have then been referred for an invasive biopsy, which can cause an infection, leading to sepsis. In addition, many men have so-called 'clinically insignificant' prostate cancers, which means that they are very unlikely ever to spread, and so do not require treatment.
According to Prostate Cancer UK, new technologies such as next generation multiparametric MRI scans, which are becoming more common, can help to prevent unnecessary biopsies. In addition, newer transperineal prostate biopsies are more accurate at separating the problematic from insignificant cancers, and reducing risk of sepsis.
What happens if I'm diagnosed with prostate cancer?
You will be referred to a specialist oncologist to discuss the next steps. There are many different paths which can be followed, depending on your circumstances and wishes.
If the cancer has not spread beyond the prostate, there are various curative options available ranging from surgery and radiotherapy, to minimally invasive treatments such as so-called focal therapy which involves zapping the tumour with high intensity ultrasound or freezing it.
Sooriakumaran says that the biopsy will also reveal whether the cancer is aggressive or low risk. For patients in the latter category, your oncologist may recommend surveillance, especially if they have other conditions like heart disease which pose a greater threat to their life, because the risk of the tumour spreading is low.
'If it has gone outside the prostate, they typically will be offered hormone therapy,' he says. 'If it's just outside the prostate, then they will have radiotherapy as well, and occasionally they might have surgery as well, depending upon how much disease there is outside the prostate.'
What are the different treatment options if I have prostate cancer?
The good news for men who are diagnosed with prostate cancer is that the range of available treatment options is increasingly broad. Sooriakumaran says that patients have a huge amount of say in what treatment they end up getting, with various advantages and disadvantages to each therapy.
Here are some of the options:
Focal therapy
Therapies such as ultrasound and cryotherapy tend to hold the cancer at bay for a few years rather than curing it, but they have far fewer side effects than other treatment options.
Surgery
This has the advantage of being a one-off procedure, but cutting a tumour out of the prostate does carry the risk of driving erectile dysfunction or urinary incontinence.
Radiotherapy
This is a better option for preserving erections, but has more side effects on bowel function, while it tends to involve regular hospital visits across the duration of the treatment course.
Hormone therapy
Newer hormonal therapies such as abiraterone are only offered for people with metastatic disease which has spread beyond the prostate. They have made a major difference when it comes to slowing down cancer progression and enabling people to live with incurable prostate cancer for much longer, but carry side effects such as hot flushes, reduced libido, weight gain and fatigue.
'It's often up to the patient to decide because some men would rather preserve their erections at all costs, and therefore may not want surgery, while some men don't want to have to come to hospital every day for six weeks,' says Sooriakumaran. 'So it's very much a personal choice, once the specialist has gone through the treatment options.