The number of prostate cancers diagnosed in UK men each year would jump from 30,000 to 160,000 if the country introduced population-wide screening for the disease, new research shows. However, many of those cancers are low-risk and may not lead to death.

Something similar happened in the United States in the mid-1990s, when giving men prostate-specific antigen (PSA) blood tests to detect the disease became standard practice, Professor David E. Neal of the University of Cambridge, one of the new study's authors, told Reuters Health.

There was an epidemic of prostate cancer in America, he said. The number of cases virtually tripled in five years.

But many of the cancers detected by PSA testing are slow-growing and may be managed best by active monitoring or surveillance, rather than radiation or surgery, which can seriously impact a man's quality of life by causing incontinence, impotence, and other side effects, he added. What we don't want to do is to treat a man at 65 who is destined to die at 85 of a stroke, Neal said.

Neal and his colleagues are currently conducting a huge study in which they've offered prostate cancer screening to a quarter of a million men 50 to 69 years old, roughly half of whom have chosen to take the test. About 10 percent of these men had high PSA levels, while roughly a quarter of these men actually had cancer.

Among the cancers the researchers identified, about 12 percent were locally aggressive, having spread beyond the prostate gland, and about a third were extremely low-risk.

In the current study, Neal and his team used data from this study-the UK Department of Health-funded Prostate Testing for Cancer and Treatment trial (ProtecT)-to estimate how many UK men would be diagnosed with prostate cancer if the country began screening for the disease and half actually agreed to be tested.

Based on these estimates and the findings from ProtecT, the researchers say, a majority of the 160,000 cancers that would be picked up by PSA testing would be low-risk. Some of these low-risk tumors might not be a threat to men's health, they add, and the best way to treat this type of prostate cancer is still a matter of debate. About one in 10 of the cancers would be advanced.

In the US, Neal said, academic urologists are now beginning to offer more conservative approaches to selected men with low-risk cancers picked up by screening.

While the UK does not offer routine PSA testing as part of standard care, all men can get the test upon request, Neal said. We're not trying to in any way stop men coming forward to be tested.

It's highly unlikely that the UK would begin doing population-based screening, he added, but research now underway, including the ProtecT trial, is going to begin to identify high-risk populations of men who should be screened, and establish which men with prostate cancer need aggressive treatment with radiation, drugs or surgery, and which can be managed more conservatively.

I'm quite confident that we will be able to do this much better, Neal said.

SOURCE: BJU International, December 2009.

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