PSA Testing: Why the NHS Doesn't Screen Every Man – and Why I Would Want to Know My PSA

Every November, Movember brings much-needed attention to men's health, particularly prostate cancer. But there's a question I think deserves more discussion.

If we have a relatively simple blood test that can help detect prostate cancer before symptoms develop, why doesn't the NHS routinely offer it to every man?

It's a reasonable question, and the answer isn't quite as straightforward as you might expect.

Prostate cancer is the most commonly diagnosed cancer in men in the UK, and early disease frequently causes no symptoms. We also have a relatively inexpensive blood test, prostate-specific antigen (PSA), that can help identify men who may require further investigation.

So why aren't we screening everyone?

The problem isn't that PSA testing doesn't work. It's that it doesn't always tell us what we really need to know.

PSA is a protein produced by the prostate gland. A small amount naturally enters the bloodstream, where it can be measured.

Importantly, PSA is prostate-specific, not cancer-specific.

Levels can increase because of benign prostate enlargement, inflammation, infection or prostate cancer. Equally, some men with prostate cancer have PSA levels within conventional reference ranges.

This brings us to two important principles of diagnostic testing: sensitivity and specificity.

Sensitivity describes how effectively a test identifies people who have a disease, while specificity describes how effectively it identifies those who don't.

PSA has limitations in both respects.

Lowering the PSA threshold for further investigation may identify more cancers, but it also increases false-positive results and unnecessary investigations. Raising the threshold reduces false positives but risks missing clinically significant disease.

There is no perfect cut-off.

And this is particularly relevant because not all prostate cancers behave in the same way.

Some are aggressive and potentially life-threatening. Others grow so slowly that they may never cause symptoms or affect a man's life expectancy.

Detecting more cancers doesn't necessarily mean saving more lives.

The UK National Screening Committee considers whether the benefits of screening an entire population outweigh the potential harms.

This follows principles originally established by Wilson and Jungner for the World Health Organization in 1968: just because we can detect a disease doesn't automatically mean we should screen everyone for it.

With PSA, the principal concerns are false-positive results, unnecessary investigations, overdiagnosis and overtreatment.

Overdiagnosis is particularly important. A man may be diagnosed with a prostate cancer that would never have caused him harm, yet still experience the anxiety of a cancer diagnosis, further investigations and potentially treatment-related complications.

These can include urinary incontinence and erectile dysfunction.

However, we also know that PSA-based screening can reduce prostate cancer mortality. Long-term trial evidence suggests a modest but meaningful reduction in deaths, although this benefit must be balanced against the considerably larger number of men exposed to unnecessary investigations and diagnoses.

It's a difficult balance, and I understand why the NHS takes a cautious approach.

But I think there's an important distinction that often gets overlooked.

When the NHS considers a national screening programme, it has to evaluate the overall consequences for millions of men.

How many lives might be saved? How many men might undergo unnecessary investigations? How many might receive treatment they never needed?

These are entirely legitimate considerations.

But when an individual asks whether he should know his PSA, the conversation is different.

We're considering his age, family history, ethnicity, personal risk factors and, importantly, his preferences.

Personally, I would want to know my PSA.

Not because I believe an elevated result automatically means cancer, or that every prostate cancer needs treating.

I would want to know because I value having information that allows me to make informed decisions about my health.

If my PSA were elevated, I'd want to understand why. If it had increased significantly from a previous result, I'd want to know whether that change was clinically meaningful.

And if further investigation were appropriate, I'd want to understand the potential benefits and risks before deciding what to do next.

Knowing your PSA, investigating an abnormal result and treating prostate cancer are three entirely separate decisions.

One doesn't automatically necessitate the next.

PSA generally increases with age, partly because the prostate naturally enlarges over time.

NICE provides the following age-specific thresholds to help guide referral decisions in men with possible symptoms of prostate cancer.

These are referral thresholds for symptomatic men, not universal screening cut-offs or absolute definitions of normal prostate health.

A PSA below the threshold doesn't exclude cancer, and a result above it doesn't confirm cancer.

Previous results can also provide useful context, although the rate of PSA change should never be used in isolation to determine whether further investigation is necessary.

As with most blood tests, the result needs to be interpreted alongside the individual clinical picture.

Men aged 50 and over in the UK can request PSA testing through their GP, following an informed discussion of its benefits and limitations.

Men with additional risk factors, including Black ethnicity, a family history of prostate cancer or inherited genetic variants such as BRCA2, may benefit from discussing testing earlier.

If you have concerning urinary symptoms or other symptoms that could indicate prostate disease, you should seek medical assessment rather than relying on screening.

And if you do decide to have a PSA test, preparation matters. Ejaculation, cycling and vigorous exercise can temporarily influence PSA, while urinary infections and certain medications can also affect interpretation.

An elevated result doesn't automatically mean you need a biopsy. Modern diagnostic pathways, including prostate MRI and appropriate risk assessment, help clinicians decide whether further investigation is necessary.

Even when cancer is diagnosed, active surveillance rather than immediate treatment may be appropriate for some men.

I don't believe the NHS is wrong to be cautious about universal PSA screening. The concerns surrounding overdiagnosis and overtreatment are genuine, and the evidence deserves to be respected.

But equally, I don't believe the absence of a national screening programme means PSA testing has little value for the individual.

Both things can be true.

As a doctor, I understand why screening programmes need to demonstrate more benefit than harm across an entire population.

As an individual, I would want to know my PSA, understand what the result means and make an informed decision about what, if anything, should happen next.

That doesn't mean everyone should make the same choice.

A blood test is information. It isn't a diagnosis, and it certainly isn't an instruction to treat.

For me, that's the important distinction.

Good medicine isn't about performing as many tests as possible. It's about understanding the information available, recognising its limitations and making decisions that genuinely benefit the individual.

And that's the conversation I think we should be encouraging this Movember.

This article reflects Dr Stevens' professional perspective and is intended for general education. Decisions about PSA testing and further investigation should be made following an informed discussion with an appropriately qualified healthcare professional.