A major review of nearly 800,000 men has found prostate cancer screening using a specific test is likely to reduce deaths from the disease, but experts shared a warning
Screening men for prostate cancer through a blood test is likely to cut deaths from the condition, a new review has discovered.
The results of the analysis, which encompassed nearly 800,000 patients, may “support a conversation” about screening using the prostate specific antigen (PSA) test, researchers stated. Despite this, experts emphasised there are still concerns surrounding overdiagnosis and overtreatment. Cancer Research UK also noted the test is “not effective enough”.
Prostate cancer is the most prevalent cancer in the UK, with over 64,000 men diagnosed annually, yet screening for the condition remains contentious. Some experts have argued the PSA test – which measures the levels of a protein produced by the prostate – is unreliable and can result in overdiagnosis. In certain instances, men with an elevated PSA level may not have cancer while those with a normal level may have the disease.
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The test can also result in the detection of harmless tumours, leading to unnecessary treatment with the risk of side-effects such as incontinence and erectile dysfunction. Now, in a significant new Cochrane review, experts have examined the results of six trials involving 789,086 patients, five of which influenced the findings. The men involved ranged from 45 to 80, but were predominantly aged between 50 and 70.
The analysis revealed that, without screening, 16 men per 1,000 would die from prostate cancer. Screening reduced this by two deaths, to 14 per 1,000 men. The latest findings represent a departure from a previous Cochrane review in 2013, which concluded that screening did not meaningfully reduce deaths.
The trials featured in the most recent research did not examine impacts on quality of life, such as complications from biopsies, sexual dysfunction and urinary problems.
However, lead author Dr Juan Franco, of Heinrich Heine University Dusseldorf, points to other studies which suggest the overdiagnosis rate lies somewhere between 20% and 50% for prostate cancer. He described the PSA as “an imperfect test” and emphasised there are “many kinds” of prostate cancer.
Dr Franco said: “There are very aggressive kinds that can cause death, but there’s also very benign forms that take the whole life to grow and perhaps never cause any problems for men. That is what we call overdiagnosis and that is another side effect related to the screening.”
He added that the test can “detect a lot of benign cancers in men that ultimately would have never had caused any problems and those men who received the diagnosis may receive treatment”.
He said: “That could be radiation, surgery, hormone therapy and they may suffer the side effects of those treatments.” Meanwhile, senior author Dr Philipp Dahm, of the University of Minnesota, said the findings “support a conversation about PSA screening”.
He said: “With new data now available, we can now say with moderate certainty that PSA screening reduces prostate cancer deaths in men with a sufficient life expectancy. This suggests that for the right patient – someone who is well-informed, has a good life expectancy and understands the full implications of screening – there is now a reasonable evidence base to support a conversation about PSA screening.
“This represents an important change in the evidence for future guideline developers and policy-makers to consider.” Dr Dahm added: “I see a lot of patients that come to me with an elevated PSA, or see a lot of patients in whom prostate cancer has been diagnosed, and then I’m in charge in advising them of treatment.
“I don’t want to take away from what guideline developers will say, but with these results I think more guideline developers may recommend prostate cancer screening for men that have certain characteristics, the most important one being that they have a long life expectancy.”
Dr Franco said: “We want to be clear that this is not a blanket endorsement of universal screening. The decision should always be made between a patient and their doctor, with a full understanding of both the potential benefits and the very real risks of overdiagnosis and unnecessary treatment.”
At present, there is no prostate cancer screening programme in the UK, though men aged over 50 are able to request a PSA test through their GP. Last November, the UK National Screening Committee (UKNSC) announced it would not back screening using the PSA test on the grounds that it “is likely to cause more harm than good”.
It solely recommended that men carrying BRCA1 and BRCA2 genetic mutations – which places them at a significantly greater risk of developing prostate cancer – should undergo screening every two years, between the ages of 45 and 61.
Responding to the conclusions of the Cochrane review, Dr Ian Walker, executive director of policy at Cancer Research UK, said: “This is the most comprehensive study of prostate cancer screening to date and highlights why there isn’t currently a widespread screening programme in the UK. Unfortunately, the test currently used to detect prostate cancer is not effective enough.
“Whilst this review does highlight that the test could save one to two lives from prostate cancer for every 1,000 men screened, it also shows that around 30 more men could be diagnosed with the disease, many of whom would never have been harmed by their disease and could go on to have unnecessary treatment with long‐term impacts like the loss of bladder control and erectile dysfunction.
“The study shows the complex challenge of balancing benefits against unintended harms when informing recommendations around screening.”
The findings come following the first men being tested as part of a groundbreaking study into prostate cancer screening.
The Transform trial, backed by funding from Prostate Cancer UK and the National Institute for Health and Care Research, will assess multiple approaches, including genetic tests and 10-minute MRI scans, to establish the safest and most cost-efficient method of screening men for the condition.
