The test that saved Ben Stiller's life: Star credits prostate screening for finding his tumour so why is it controversial?

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Ben Stiller's prostate cancer battle has brought the disease back into the spotlight and with it, the debate over whether men should be offered routine screening.

He revealed his tumour had been growing for five years and credits the prostate-specific antigen (PSA) tests he had done, with saving his life.

The Hollywood actor revealed he was diagnosed with an 'aggressive' form of cancer two years ago - and secretly had surgery to remove his prostate. 

By September that year, he was told he was cancer-free. 

Now, he is urging men to speak to their doctors about being tested at an earlier age.

Ben Stiller has revealed he was diagnosed with prostate cancer two years ago. He credits a PSA test with saving his life so why are the tests still so controversial?

He posted a provocative essay on the website Medium called 'The Prostate Cancer Test That Saved My Life'.

In it, he says his doctor had been monitoring levels of PSA in his blood from the age of 46.

But in both the US and UK, the screening he talks about is not offered routinely as it has been associated with a range of issues, namely its accuracy.

While raised PSA levels in the blood may be a sign of prostate cancer, it can also be caused by other conditions, such as an enlarged prostate or a urinary infection. 

It is also linked to potential harmful consequences, such as erectile dysfunction or incontinence, which is why there is currently no national screening programme for prostate cancer in the UK.

Every year more than 47,000 British men are diagnosed with the disease, a rise from 35,000 in 2009. 

Under NICE guidelines, a wait and see policy — officially called active surveillance — should be offered as a first option when prostate cancer is considered low risk.

Raised PSA levels in the blood may be a sign of prostate cancer but it can also be caused by other conditions, such as an enlarged prostate or a urinary infection

This means it is contained in the gland, has a Gleason score below six and the man's PSA test result is below ten.

Meanwhile, the Preventative Services Task Force (USPSTF), which issues medical guidelines that are widely followed by doctors in the US, says no man of any age should have the test unless there are urological symptoms.

Here, we speak to two experts with opposite views on whether routine screening of the prostate should be carried out. 

YES

Marc Laniado is a consultant urologist at Wexham Park NHS Hospital in Surrey and Windsor Urology. He says:

Who knows how many of the 10,000 UK men who die from prostate cancer each year might have potentially been saved by a national screening programme?

The key to treating cancer is spotting the disease at the earliest possible stage, when effective treatment is still possible. 

Screening programmes - as we have for breast, bowel and cervical cancer - are a wonderfully effective tool for making a diagnosis before any symptoms.

But this is unlikely if you are unfortunate enough to develop prostate cancer.

For there is no national screening programme and, unless you're a persistent patient or seen by a motivated GP, you will be dissuaded from testing. 

Marc Laniado is a consultant urologist at Wexham Park NHS Hospital in Surrey and Windsor Urology

And it's likely that your diagnosis will be delayed, frustrated or even blocked.

I despair at the number of patients I see who could have been saved by screening. 

Patients like the man in his mid-50s who came to me recently with prostate cancer that had already spread to his bones.

He'd seen his GP after suffering some urinary symptoms (important signs to watch out for include blood in the urine and going to the loo a lot - especially at night).

Yet despite a family history of prostate cancer - itself a red flag for investigation - the doctor told him he didn't need a PSA test. This is a blood test that measures prostate specific antigen (PSA) a protein produced by the prostate.

Raised PSA may be a sign of cancer, but it may also be caused by other conditions, such as an enlarged prostate, or a urinary infection. 

Why did his GP put him off? It may well have been for the same reasons the UK National Screening Committee has again failed to recommend a screening programme for prostate cancer.

Typically, sceptics say PSA tests are unreliable, that they can suggest prostate cancer when no cancer exists, that they lead to invasive and sometimes painful biopsies for no reason, and that they sometimes lead to unnecessary treatment with side-effects.

I can only hope the GP wasn't also thinking about the cost of the test. Whatever the reason, my patient went along with it.

But two years later the GP relented and did carry out a PSA test; the results were borderline high and the man was referred to me. When I looked at his scans, it was clear the disease was incurable.

I wish I could say this case was unusual, but far from it.

Another man I saw recently had gone to his doctor with urinary symptoms and was initially given medication for a urinary infection.

He was given a PSA test months later, after the infection had been treated, and, as the results were high, he was sent to me.

'With some refinement, we could have a screening programme that could save lives' argues Mr Laniado

When I saw the scans, I was horrified to discover the disease had metastasised - that is, had broken through the prostate and spread. Despite radiotherapy, chemotherapy and hormone medication, he died. He was 60.

Prostate cancer is almost as common as breast cancer and women in the UK are screened for breast cancer even though the benefits have been repeatedly debated. 

So why don't we screen men? I accept the deficiencies of the PSA test - cycling, recent ejaculation and urinary infections can all raise levels temporarily and may cause false-positive results. 

And, yes, a biopsy after a PSA test to confirm diagnosis can lead to infection (as a sample of tissue is removed from the prostate using a thin needle via the rectum). 

And this infection can be life-threatening in 1 to 4 per cent of cases. It is true, too, that unguided biopsies - done without a prior MRI scan - can miss a tumour, for example, if it sits at the front of the prostate.

But with some refinement, we could have a screening programme that could save lives.

It would work a bit like this: Men over 50 would be routinely offered a PSA test. 

This would be assessed alongside other risk factors such as family history and ethnicity (black men are at an increased risk).

Men with normal readings would be recalled in five years. 

However, if there is deemed to be a risk, then the patient would be sent for a high-definition scan, known as a multi-parametric MRI.

Prostate cancer is almost as common as breast cancer and women in the UK are screened for breast cancer even though the benefits have been repeatedly debated, says Mr Laniado

This would show which men might reasonably avoid having a biopsy because the prostate looks completely normal. And they would provide more accurate guidance for those men who do need to have one.

Doubtless some will quibble about cost. But if you go to your doctor with a sore knee you're likely to be referred for an X-ray at the drop of a hat. Sore knees, as far as I understand, don't cost lives.

But prostate cancer does - and will continue to do so, as long as we have a haphazard, unstructured system that fails to harness the best that modern medicine can offer.

And urologists like me will continue to see patients who potentially missed out on a chance for timely treatment and for their lives to be saved.

NO

Dr David Jewell is a Bristol based GP and former university lecturer with an interest in men's health. He says:

At 65 years old, I've never had a PSA test, the test that zealous supporters of a prostate cancer screening programme will argue is vital for detecting the disease.

And as long as I remain free of any symptoms which may suggest prostate cancer, I have no intention of ever having one. 

Dr David Jewell is a Bristol based GP and former university lecturer with an interest in men's health

I certainly don't believe we should have a national screening programme for the disease.

 It's not reckless overconfidence - as a GP with an interest in men's health, I simply don't believe the data supports the argument for screening.

It's why I actively discourage patients who come in requesting a PSA test after they've heard someone in the pub talking about how every man over 50 should have one. In the absence of any symptoms, I tell them it is far better to leave well alone.

Am I being irresponsible? Quite the opposite. The PSA test as a measure for detecting prostate cancer is flawed on many levels.

A major problem is that there are no clear levels to distinguish men with or without cancer.

For example, a PSA reading of four or lower in men over 50 is usually considered normal, but some men with this reading will have prostate cancer. 

Yet although a PSA above ten is a sign that cancer is more likely to be present, it can also be caused by an enlarged prostate, which is not cancer.

It hardly inspires confidence.

Indeed, according to Cancer Research UK, up to two out of three men with raised PSA don't have cancer. 

Conversely, up to 20 per cent of men with prostate cancer have normal levels.

The problems don't end there. Men with a high PSA reading will need further tests, such as a biopsy (which involves the charming procedure of having a needle inserted into the rectum). 

It may cause bleeding or infection and, after all that, one in five tests fails to pick up prostate cancer.

And what if a biopsy does confirm cancer? If the disease has broken out of the prostate capsule - a thin layer of connective tissue that surrounds the prostate gland - then it is already at an advanced and potentially fatal stage.

Every year more than 47,000 British men are diagnosed with the disease, a rise from 35,000 in 2009, the latest statistics show

Yet if it is contained within the prostate, a doctor cannot say with certainty whether what they have found is a slow-growing cancer that would never cause any problems in a man's lifetime.

For screening to be really useful, it would only pick up prostate cancers that are faster-growing and likely to be a threat to a man's health. But there is currently no test that can reliably do that.

If that weren't enough to convince, take a look at the treatment, which, ironically, can vastly reduce quality of life. 

Removing the prostate can lead to horrible side-effects, such as erectile dysfunction or incontinence.

Frankly, it would be madness for a symptom-free and otherwise healthy male to submit himself to this.

Even the man who 'invented' the PSA test, Richard Ablin, has criticised its use as a screening tool for this very reason - the overdiagnosis and overtreatment of men. (He'd actually devised the test as a way of monitoring the effectiveness of prostate cancer treatment, to check if the patient's PSA levels dropped.)

Ah, but what of the persuasive specialists who seem instinctively driven to screening and treatment? 

If you were a highly skilled surgeon, trained in the complex field of radical prostatectomies, wouldn't you feel it was the best option? 

And if you were a patient, worried that cancer is death just spelt with different letters, wouldn't you regard your consultant as your life raft?

You'd tell yourself their knowledge is irrefutable.

Yet in my view they do not pay sufficient attention to the real-world effects of screening and how it leads to so much over-diagnosis and overtreatment.

In contrast, as GPs who know our patients and their backgrounds, we have context. We're not just here to showcase our surgical skill.

We can assess motivation for making a request for a PSA - from understandable concerns about family history to arbitrary, water-cooler chit-chat about general health. 

And, of course, if you're having symptoms, a GP should always take them seriously.

That's not to say all screening is ineffective - some programmes make all the difference, for instance, testing newborns for the genetic condition phenylketonuria (PKU) means treatment is started straight away, cutting the risk of serious brain damage.

But prostate screening would not be one of them.