WATANI International
26 September 2010
The UK national screening programme would rule out the risk in half of the male population and also identify those most in danger of dying from the disease, the second most deadly cancer in men.
The procedure, which costs just £10, would allow doctors to concentrate their scarce resources on those most susceptible to developing and dying from the condition.
Controversy currently surrounds the tests, which are already available, as there has been debate over when is the optimum time to administer it. The fear is many men could be “overdiagnosed” and be so worried they will undergo unnecessary and risky surgery.
But the new report suggests that 60 is a watershed age and having one then can definitely eliminate the risk of the disease becoming life-threatening in up to 50% of men, eliminating the need for them to be screened in future, experts said. It would also help doctors predict which men may be susceptible to death from the cancer or to metastasis – where the disease spreads to other organs – and monitor their health accordingly.
Professor Mark Emberton, a leading prostate cancer expert at University College, London said the test could help get thousands of men off the “diagnostic conveyor belt”.
“It may be that PSA is actually a much better prediction of long-term outcome than we thought,” he said. “The key question is not ##do you have prostate cancer## because most men are going to get it. The key thing is ##do you have clinically important prostate cancer, cancer that will have an adverse effect on your life. “I think this is a potential route out of the diagnostic conveyor belt from which there has been no exit before.”
The simple tests works because it highlights levels in the blood of prostate specific antigen (PSA), a protein that can leak from the prostate gland and tumour cells. Some 90% of deaths from prostate cancer occur in men with the highest levels of PSA. Because it is generally slow to develop, taking up to 15 years to spread to other parts of the body, scientists believe that men with below-average PSA levels at the age of 60 need not worry about the threat.
Doctors would then be able to focus their attention and resources on those at risk from the disease, while patients with low PSA would not need to be exposed to potentially dangerous screening and treatment later on in life.
Prostate cancer is the most prevalent cancer among British men, affecting a third of men over the age of 50. It is second only to lung cancer in terms of loss of life.
Charities last year called for national PSA screening to be introduced in Britain after a study indicated that such a programme could save 2,000 lives a year. But doctors disagree over how valuable the testing is because more than 65% of men with high PSA do not have cancer, raising the risk of misdiagnosis.
But the latest study raises the possibility of men with low PSA being excluded from any further prostate cancer testing such as biopsies, which can cause impotence and incontinence, at a later date. Dr Hans Lilja, who led the study, said it “adds to the arguments” for the introduction of national screening programmes. He added: “With screening there is a balance of benefits and harms and obviously if we can be more clever in how we sift the benefits from the harms and identify that a man at the age of 60 would not benefit substantially from any further testing then I think we are shifting that balance.”
John Anderson, Vice President of the British Association of Urological Surgeons, said the “exciting” study showed that a targeted approach to testing was preferable to a screening programme, which could see men tested at regular intervals over several years. He said: “What we have got so far is a debate as to whether we should have screening or not. “The study does a snapshot at the age of 60 and the evidence is that that is where we need to focus our energies on.”
The research, published in the British Medical Journal, was based on research by doctors at the Memorial Sloan-Kettering Cancer Center in New York and Lund University in Malmo, Sweden. Experts took blood samples from 1,167 men aged 60 in 1981 and followed their health up to the age of 85.
The team, led by Professor Lilja, wrote: “Our findings suggest that 60 year old men with low concentrations can be reassured that even if they do harbour cancer, it is unlikely to become apparent during their lifetime and even less likely to become life threatening.
“None the less, a raised PSA is far from being an inevitable harbinger of advanced prostate cancer … while a concentration below the median can probably ##rule out## subsequent death or metastasis from prostate cancer, higher concentrations indicate only that careful monitoring might be warranted.”
According to the study, the quarter of men with the highest PSA at age 60 have a 26 times greater chance of dying from prostate cancer than those in the lowest quarter.
However, having a high PSA does not make advanced prostate cancer inevitable. Of the five per cent of men with the highest levels of PSA, only one in six will die of prostate cancer by the age of 85, the study said.
Dr Sarah Cant, Head of Policy and Campaigns at The Prostate Cancer Charity, said the study presented an “interesting proposition which takes the ongoing PSA debate in a new direction”.
She added: “However, this is an early study, involving only 1,000 men in Sweden, and long-term research in a greater number and range of men would be needed before we can say whether this approach would work.”
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The Daily Telegraph (abridged)