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The potential for blood tests that detect cancer is huge.

But what if a test is, in some ways, too good? What if it finds cancers that if left undetected wouldn’t cause a person any harm? And what if it’s not possible to know for certain which cancers need to be treated, or who could avoid a life-altering diagnosis and potential long-term treatment side effects?

This is the situation right now with prostate cancer.

There’s no UK screening programme for prostate cancer. That’s because the blood test that would be used – called the PSA (or prostate specific antigen) test – isn’t reliable enough.

Men over the age of 50 with no symptoms of prostate cancer can still ask for the test in the UK. But its use is hotly debated around the world.

Now, a new Cancer Research UK-funded study, from scientists at the Universities of Bristol and Oxford, sheds more light on how unreliable the test is. And it confirms that for men without symptoms, the PSA test doesn’t save lives.

What is the PSA test?

Prostate cancer is the most common cancer in men, with 46,690 cases diagnosed each year in the UK.

The PSA blood test is one of the main ways, along with a rectal exam, that doctors can look for signs of prostate cancer.

The test measures the level of PSA in a blood sample. And while it’s normal for men to have some PSA in their blood, a raised level can be a sign of prostate cancer.

But PSA can be raised for lots of other reasons too, meaning a man might get an abnormal result when he doesn’t have cancer.

PSA test prostate cancer screening

Copy this link and share our graphic. Credit: Cancer Research UK

It’s this, combined with the test missing some cancers and finding others that would never cause a man any harm, that makes it unreliable for screening.

What does the new study show?

The CAP trial is the largest to date looking at whether the PSA test can reduce the number of men dying from prostate cancer. It includes over 400,000 men from almost 600 GP practices in the UK. Some practices invited men aged 50 to 69 for a one-off appointment with a nurse where they were offered information about PSA testing and, if they wanted it, the test. The rest operated as normal, and didn’t invite men for the test.

After an average of 10 years, the researchers found that the one-off PSA test led to many more prostate cancers being found. But crucially, the men who had the test were no less likely to die of prostate cancer than the men that hadn’t had it.

This suggests that giving a one-off PSA test to men without symptoms doesn’t save lives from prostate cancer, because it:

  • Picks up cancers that are unlikely to cause a person any harm
  • Misses cancers that are aggressive and probably would benefit from treatment

Professor Richard Martin, who led the study from the University of Bristol, says the results show that giving a one-off PSA test to men without symptoms “risks diagnosing more men with a cancer that would never have caused them any harm”.

“In some cases, this might mean men unnecessarily living with the stigma of having a cancer and the side effects of treatment that was not needed, such as incontinence and erectile dysfunction, for many years, maybe even decades,” he adds.

This backs up a study from 2013 that pooled data from 5 of the largest and most rigorous trials on prostate cancer screening. It too found that the test leads to many men being diagnosed with a cancer that did not need to be found. And that screening for prostate cancer using the PSA test doesn’t reduce the number of men dying from the disease.

PSA prostate cancer screening data

Copy this link and share our graphic. Credit: Cancer Research UK

What’s the problem with finding more prostate cancers?

It seems counter-intuitive to suggest that some cancers would be better off left alone. Especially when early diagnosis can boost treatment success for some cancers. But these overdiagnosed cancers pose a serious problem.

What is overdiagnosis?

Some cancers grow fast and spread quickly, but some grow so slowly that if they went undetected they wouldn’t cause a person any problems. People with these harmless cancers won’t have any symptoms, and they won’t die from the disease.

In other words, it doesn’t matter if the cancer is never found.

When these slow-growing cancers are found they’re said to be overdiagnosed.

Read more: Overdiagnosis – when finding cancer can do more harm than good

Unfortunately, there’s no way of telling apart the cancers that need to be found and treated and the ones that could have been left alone. This means that some patients will receive an unnecessary diagnosis, unnecessary treatment, and the emotional and physical side effects they come with.

Richard Roope, a GP and one of Cancer Research UK’s senior clinical advisors, says this highlights the challenge of diagnosing prostate cancer early.

“Some areas of medicine are very clear cut, others less so,” he says. “PSA testing falls very much into the latter. Prostate cancer comes in many shapes and sizes, ranging from the aggressive to the very slow growing. Unfortunately, no available test will discriminate between these.

“What we know is that giving men without symptoms a PSA test does not change the ultimate outcome if cancer is present, meanwhile any treatment used may produce unpleasant side effects.”

What should you do if you’re worried about prostate cancer?

This study shows that having a PSA test when you don’t have any prostate cancer symptoms comes with some serious risks. If you’re still thinking about having the test, it’s important to get the full picture to help you decide. Our website and your doctor can help.

For those with symptoms, or if you notice anything that’s not normal for you, visit your doctor. In most cases it won’t be cancer, but it’s still best to get it checked.

What next for prostate cancer research?

Over 11,000 men die from prostate cancer in the UK every year. And Professor Martin says it’s here that research must be focussed.

We’re not saying that screening for prostate cancer should be discounted. What we’re saying is PSA testing for prostate cancer is not the answer

– Professor Richard Martin

“Finding a way to detect and successfully treat these cancers, ones that are aggressive and harmful, is what we must continue to strive for.

“We’re not saying that screening for prostate cancer should be discounted. What we’re saying is PSA testing for prostate cancer is not the answer.”

One of the most pressing challenges for researchers is finding a way to distinguish the potentially lethal cancers that need treating from the harmless ones that don’t. This would be an important first step in addressing the problem of overdiagnosis of prostate cancer.

One area that’s showing promise is the use of specialised scans. A type of MRI has shown potential in clinical trials as a way of reducing the number of men who need to go through uncomfortable prostate biopsies. The scans could also help accurately map the size and location of prostate tumours and to identify those cancers that are more likely to be aggressive and need treatment.

Our goal is to save men from harm. This means finding a way to stop men with aggressive prostate cancer dying from their disease by developing better tests and more effective treatments. But as the latest research shows, this also means sparing men with harmless cancers an unnecessary but life-altering diagnosis.

Katie Edmunds is a health information officer at Cancer Research UK

Comments

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Nick Peel April 10, 2018

Hi Ken,
Thanks for your comment.
If what you’ve read concerns you, we’d recommend chatting about the latest evidence and the content of your slides with your contact at Prostate Cancer UK.
As Cancer Research UK, we’re unable to help on this one.
Best wishes,
Nick, Cancer Research UK

Jeff Haddock April 9, 2018

I may have missed it but why no mention of the STHLM3 testing?

Ken Green April 9, 2018

For the last three years I have been giving regular prostate cancer awareness talks on behalf of PCUK to companies, clubs, etc, using the Prostate Cancer Awareness slideshow. Some of the slides describe the PSA test as a way of diagnosing possible cancer, and informing attendees that they are entitled to a test if they are over 50, even if they have no symptoms. After reading the above this seriously concerns me, as I feel the slides need to be amended. Can someone in PCUK take this forward?

Martin B April 4, 2018

Test

Tony T April 3, 2018

Having read all of the posts I am fast coming to the conclusion that this article (whilst being interesting) has no real value to anybody looking for a steer on the best way to discover whether they have prostate cancer or not.
My advice to any man who finds it difficult to Pee, gets up regularly to pee at night or has other symptoms is to forget what they have read in the article and speak with their GP who has a duty to refer to a consultant (if they think you are at risk) within 2 weeks. Only an expert such as a Urologist is in a position to test and make a proper judgement and although a DRE or a PSA test is an indicator the science is often unreliable and should be treated as such.

Karen Mackulin April 3, 2018

Thank you for a very informative article about the pitfalls of using PSA as a test for prostate cancer. My father had prostate cancer for about 20 years that had no adverse effects on his life; ironically he died of throat cancer! My brother on the other hand was diagnosed with prostate cancer about 7 years ago. He has a more aggressive kind and regularly has hormone injections which, to date, have kept the disease in check. Thank you for all the great research you continue to do!

Katie Edmunds April 3, 2018

Thanks for all your comments.

We’ve noticed that several responses touch on the same points, and wanted to address them here.

First, when we talk about a one-off PSA test not saving lives from prostate cancer, we’re talking specifically about it being used for screening in men without prostate cancer symptoms.

For anyone experiencing symptoms, or anything that isn’t normal for you, tell your doctor. The chances are it’s not cancer, but it’s better to check with a doctor. The PSA test is one of the things your doctor might suggest to help work out what is at the root of your symptoms, but they’ll be able to talk to you about what tests they think you should have and why. In this instance, the PSA test is being used as part of several routes of investigation.

While the study covered in this blog post specifically looked at a one-off PSA test in men without symptoms, previous studies have looked at whether or not multiple tests could be of benefit. The results of this research have been mixed, but when the results of these trials were combined in a large review in 2013 it also showed that no lives were saved from prostate cancer, and some men were diagnosed with cancers that if left undetected wouldn’t have harmed them.

Unfortunately, it’s not yet possible to tell the difference between prostate cancers that need treating and those that can be left alone. While Gleason scores and MRI scans can give us a good indication of how aggressive or advanced someone’s cancer may be, they aren’t perfect. It’s not possible to know if a person’s life has been saved, or when their prostate cancer would have been diagnosed, had they not had a PSA test.

This is why it’s crucial that research continues to try and find ways to detect and successfully treat aggressive prostate cancers.

Cancer Research UK will be funding the CAP trial for a further five years, and will continue to monitor research into PSA testing closely. We’re also funding other research into prostate cancer, including a recently announced study looking at MRI scans.

Best wishes,
Katie, Cancer Research UK

Terence carrigan April 3, 2018

I can not believe what I have just read, your headline
“Why a one-off PSA test for prostate cancer is doing men more harm than good”
This looks like it come from one of the daily tabliods rather than the CRUK. Who bases their prognosis on just one PSA test? Surely a DRE would be carried out and then a MRI scan so a full transperineum biopsy could be carried out. Then and only then would a prognosis be made. It has taken men years and years to start talking openly about Prostate Cancer (because men unlike women do not talk about such things) and this article has just put that back by about fifteen years, men will think its not worth having the PSA test as if its high the doctors will go in there with all guns blazing, thanks CRUK.
In late 2013 I had blood in my urine for about 30 hours, GP sent me for blood tests etc. My PSA was 7.19 but a DRE showed up the left lobe of the prostate to be enlarged and had hard knobbly bits on it (my words). I had a MRI scan, bone scan and then a full transperineum biopsy and from that I was diagnosed in early April 2014 it was a Gleason score 7. So I opted for hormone injections, HDR Brachytherapy and external beam Radiotherapy in case it had spread out of the prostate.
Yes there is collateral damage but without the treatment I don’t think I would still be here. More men are killed by Prostate Cancer than women are killed by breast cancer. The article also seems to imply that some men with cancer feel ashamed? What century was this written in.

Charles Carr April 2, 2018

This s completely counter intuitive. I was diagnosed with an aggressive Prostate Cancer only because I went for a routine annual company medical. It saved my life and I would have otherwise have gone undiagnosed as I had no symptoms. I have encouraged all my male friends to go get a PSA test and I stand by that advice. To not get checked for the single largest killer in the UK makes no sense!

Pauline Atkinson March 30, 2018

Until there is a better way of checking for prostate cancer the PSA test can help as it might lead to scans and biopsies. I object to the idea that men might be stigmatised if they have cancer.

Mike Lingwood March 30, 2018

I am quite sure that dissuading men from having PSA tests is a very bad a idea. Regular PSA testing and then reacting if and when there is an unusual increase is, in my opinion, the way to go. Next step a multiparametric mri scan and if this reveals cancer then a targeted biopsy using the scan data should enable an accurate diagnosis. After a few years of seeing my PSA gradually rise a significant increase prompted me to follow this route and I had a prostatectomy 2 years ago and now have undetectable PSA. As I had no symptoms, without the PSA testing and subsequent investigations, I would not have been aware that a significant cancer was developing close to the perimeter of my prostate!

Kerry Hodgson March 30, 2018

I had an annual PSA and DRE for years. However a change in velocity of the PSA test plus a weakening urine flow called for further examination. The result was gland confined prostate cancer Gleason score 7. I opted for a prostatectomy and the PSA reading has been negligible for almost 4 years.. I am a firm believer in the PSA test, bearing in mind, it’s the change in velocity which is the key.

Prof Brian Austen March 29, 2018

My PSA was measured at 25 three years ago. Biopsy showed Gleason T3 I think it was, cancer outside the prostate but not in the bones. I had the op. PSA undetecatable since. Without the PSA test I would never have known. I had colleagues that were diagnosed too late, and are dead now. I dont know why my GP ticked the PSA to be tested, but Im glad he did!!.

Patrick McGroggan March 28, 2018

I’ve had over the past years colonoscopy procedure, if your in that age group, why can’t they carry out the procedure to check the prostate, your in there, as I remember around 30 minutes, maybe in which time it could be done.
There may be some reason why this can’t be carried out, just an an observation on my part….

Andy Golding March 28, 2018

I am even more confused especially as I always thought early diagnosis was always best. I have several of the associated symptoms and will be seeing my G.P. soon. What do I do if he doesn’t advise a P.S.A? Really wished I hadn’t read this.

Sandy Tyndale-Biscoe March 28, 2018

Very depressing indeed to see that CRUK (generally regarded as the UK’s foremost cancer related charity, and one to which the largely ill-informed public is most likely to donate) have failed to notice most of the research that has gone on in this area since the turn of the century, and are still pedalling advice based on evidence that is hugely out of date. The introduction of two key changes in PCa management over the past 10 years (MRI pre-biopsy, and Active Surveillance for low risk disease) have resulted in vastly reduced incidence of over-treatment and over-diagnosis, the only “harm” that can arise from PSA testing.
The disastrous and wrong 2012 recommendation from the US Preventive Services Task Force (USPSTF) not to routinely screen asymptomatic patients to detect early disease has, as predicted by those who understand the issues, now resulted in a significant increase (by about 75%) of men first presenting with higher-risk (Gleason 8 or more) disease. Treatment of these patients will be more problematic and more of them will die. The ill-informed attitudes displayed in this article are contributing to this rise in likley mortality.

Keith Cregan March 28, 2018

My father died of prostate cancer when he was 67. I have been having the PSA test once a year for approximately 35 years.my brother who lives in Australia has been having the PSA test twice a year. He developed prostate cancer 5 years which was aggressive and if he was only having the PSA test once a year he might not have survived.

Anthony Trigwell March 28, 2018

I cannot believe this article is being published by CRUK after all their comments over the years about early diagnosis.
Having just lost a brother with this cancer ( he was late diagnosed and it was in the bones before they found it) he lived in pain for 15 years. I can assure you if you asked any of my family about UNNECESSARY DIAGNOSIS their answer would be do not be so B****Y DAFT.
I am also certain that any GP with symptoms (however mild) would be seeing one of their mates in Urology ASAP…
Regards

Roger Bacon March 28, 2018

What I don’t understand about this study is that men were only given 1 PSA test, which produces a ‘baseline’ result. For screening to be effective then it should be repeated every few years, like breast cancer is 3 yearly screened. So why did this trial not repeat the PSA tests every 3 years or so? Almost certainly if a trial for women had been conducted where they were screened for breast cancer just once and then left with no further checks, the outcome would have been the same – breast cancer screening does not save lives! What an outcry that would have caused. Talking of over treatment due to PSA testing, there are 18,000 breast cancers found each year and a review in 2012 found around 4,000 are over diagnosed, information found on CRUK website! I truly believe, along with a lot of other men who have posted comments, that this research was ill conceived and has resulted in GPs now giving out distorted information to men about the PSA test. As chairman of PCaSO, a prostate cancer support charity with over 1100 members, we will be making our membership aware of what CRUK have done, as well as notifying the National Federation of support groups who will alert their member organisations to the fact that GPs have yet again been given negative information about the PSA test. PCaSO will continue to offer free PSA tests to any man.

Richard Perkins March 28, 2018

I am surprised by the level of the strong opinion which, in the main, appears to be antagonistic
towards the results of the research. An important point to bear in mind, in my view, is that the sample used was for men “WITHOUT ANY SYMPTOMS”. I would imagine that any sample of men WITH symptoms would have produced a different result showing that the PSA test was useful as a first step in diagnosing cancer? I would welcome, from the results of more research, much better guidance on the SYMPTOMS which would lead me to be concerned enough to obtain medical advice. More research, please! I hope that a more reliable screening test can be found, soon!

Alex Mcintyre March 28, 2018

I was thinking of a test I have a brother with it I am 64 years old I always hear get checked from TV stars etc I have a few symptoms but confused should I shouldn’t I my doctor just said just because your brother got it doesn’t mean you will get it and ended the conversation thanks

Jeanne Hewton March 28, 2018

I so agree with this and am grateful to still have my husband, Eric.
The first test provides a baseline. Then subsequent PSA tests can indicate progress of the disease. Surely this makes sense.
I am surprised that an established organisation like Cancer Research should be following what is now considered as outdated thinking.
Surely, until better tests are found, regular PSA tests are better than nothing.

david mitchell March 28, 2018

I thought this information very useful and confirms my current understanding about the test.