David Cameron has become the latest high-profile figure to back growing calls for the NHS to start screening men, or at least those at highest risk, for prostate cancer after being treated for it himself.
He joined Olympic cycling champion Chris Hoy and prostate cancer charities in saying that recent advances in diagnosing the disease mean that testing can be introduced that is much safer than traditional methods, which can produce both false-positive and false-negative results.
However, others, including Cancer Research UK, disagree.
On Thursday, the UK National Screening Committee will meet to discuss the latest evidence on the subject. The independent committee, which advises ministers, is under pressure to allow testing to begin of those men at highest risk: black men, those with a family history of prostate, breast or cervical cancer and men who carry the BRCA1 or BRCA2 gene.
What is prostate cancer, what are its symptoms and which groups are most at risk?
Prostate cancer develops in the prostate gland.
It is the second most common cancer in the UK, after breast cancer, with about 55,300 new diagnoses and 12,200 deaths every year. It is the most common male cancer. Almost 80% of men diagnosed with it survive for at least 10 years.
It often does not have any symptoms in its early stages. But changes in men’s urination habits – for example, needing to pee more often, including overnight – can indicate its presence, as can erectile dysfunction.
It mainly affects men over 50. But three groups of men are most at risk: black men; those with a family history of prostate cancer, or breast or ovarian cancer in female relatives; and men who are carrying the BRCA1 or BRCA2 gene variants.
Black men are twice as likely both to get it and also to die from it. A quarter of black men will be diagnosed with prostate cancer in their lifetimes, compared with one in eight of the general male population.
Black men in England are also more likely to be diagnosed with late-stage prostate cancer than their white counterparts. Socioeconomic circumstances and genetics are believed to be contributing factors for that greatly increase risk.
How is prostate cancer detected?
All men over 50 can request a PSA test to check if they have prostate cancer. Those men, and those in the higher risk groups, can talk to their GP about the pros and cons of having the test.
GPs no longer need to assess a man’s prostate via a rectal exam. Men deemed at a higher risk have historically been offered a biopsy, in which a needle was inserted into their prostate.
A PSA test checks the level of prostate-specific antigen (PSA) in the blood. Other conditions can cause a raised PSA level, including an enlarged prostate and prostatitis, not just prostate cancer.
Unlike smear tests for cervical cancer and mammograms for breast cancer, the PSA test is not a test per se for prostate cancer. It is useful, but not definitive.
Although any man can ask their GP for a test, and GPs will usually refer anyone over 50 who requests one, routine PSA testing is not offered on the NHS. This is because blanket PSA testing could lead to overdiagnosis of prostate cancer and result in men undergoing unnecessary biopsies and invasive treatment, including surgical removal of the prostate.
For example, some studies have shown that black men may have higher PSA levels than their white counterparts, and that using the PSA test in men with no prostate symptoms does not reduce the number of prostate cancer deaths.
Why doesn’t the NHS screen men for prostate cancer?
The UK routinely screens people for breast, bowel and cervical cancer, but not prostate cancer, despite its prevalence.
Screening for it is not as straightforward as for the other cancers because of the historic weaknesses in the PSA test – the likelihood of both false positives and false negatives – and historic lack of alternative methods of screening.
The UK national screening committee (NSC), independent experts who advise ministers, is due to decide on Thursday if the NHS should start screening either all men, or those in some or all three of the higher-risk groups, for the disease.
It has come under intense pressure in recent months to rethink its position on screening. It has spent months collecting and analysing evidence.
Charities such as Prostate Cancer UK and Prostate Cancer Research say the NSC should approve at least targeted screening of men in the three higher-risk groups. Doing so would detect more cases and thus save more lives, they say.
Lithuania (2006), Kazakhstan (2013) and Sweden (2020) have already introduced screening for many or all male citizens aged at least 50.
What are the arguments for and against targeted prostate cancer screening?
Prostate Cancer Research insists recent advances in diagnostic testing mean that screening could be introduced with far fewer risks than those the PSA test involves.
Men could be safely screened using a PSA test, followed by a pre-biopsy MRI scan – “which rules out cancer in a large proportion of cases” – and then, if needed, a transperineal biopsy, thus sparing many of them the rigours and risk of a traditional biopsy.
“The core safety objection to screening has fundamentally been engineered out of the system,” it says.
Prostate Cancer UK says it will respect the decision of the NSC's evidence review, but that medical advances had made screening safer than ever before.
“We believe the evidence shows that screening men at highest risk is safe and more beneficial than the harms that might come from the screening programme,” said Chiara De Biase, its director of health services, equity and improvement.
“Pre-biopsy MRI improves the detection of clinically significant prostate cancer and reduces the risk of diagnosing cancers that don’t need treatment. We hope the committee agrees and we urgently await the outcome,” the charity says.
However, others, notably Cancer Research UK, maintain that there is still too much “conflicting evidence” around screening to justify even a targeted programme. “The evidence is still very unclear on targeted screening,” says CRUK’s Naser Turabi.
What could a prostate cancer screening programme look like?
The TRANSFORM prostate cancer screening trial may provide the answer. The £42m trial is the biggest and most ambitious prostate cancer screening trial for 20 years.
It is intended to discover the most effective and least harmful methods to screen the UK’s adult male population and catch the disease in its early stages. Three hundred thousand men will be recruited to the trial.
It is led by Prostate Cancer UK and is due to report in 2027. The NSC has agreed to look again at prostate cancer screening in the light of TRANSFORM’s findings. The National Institute for Health and Care Research is covering £16m of the £42m cost.
The study will also look at how current testing methods, including PSA blood tests, genetic spit tests and MRI scans, can be used more effectively when screening for the disease.
Dr Sam Merriel, of the Centre for Primary Care and Health Services Research at the University of Manchester, said: “Better evidence using modern approaches to prostate cancer screening that incorporate the latest tests, including prostate MRI and genetic testing, is urgently needed to find better ways to screen for prostate cancer than relying on PSA alone.”
