Tests for prostate cancer ‘risky and of little use’

The publication of data from the two new studies should change the discussion, said Dr David F. Ransohoff, a cancer epidemiologist at the University of North Carolina.

“This is not relying on modelling any more,” he said. “This is not some abstract, pointy-headed exercise. This is the real world, and this is real data.” Dr H. Gilbert Welch, a professor of medicine at Dartmouth who studies cancer screening, also welcomed the new data. “We’ve been waiting years for this,” he said. “It’s a shame we didn’t have it 20 years ago.”

Both reports were published online on Wednesday by The New England Journal of Medicine.

One involved 182,000 men in seven European countries; the other, by the National Cancer Institute, involved nearly 77,000 men at 10 medical centres in the United States.

In both, participants were randomly assigned to be screened — or not — with the PSA test. In each study, the two groups were followed for more than a decade while researchers counted deaths from prostate cancer, asking whether screening made a difference.

The European data involved studies with different designs. Taken together, the studies found that screening was associated with a 20 per cent relative reduction in the prostate cancer death rate. But the number of lives saved was small — seven fewer prostate cancer deaths for every 10,000 men screened and followed for nine years.

The American study, led by Dr Gerald L. Andriole of Washington University, had a single design. It found no reduction in deaths from prostate cancer after most of the men had been followed for 10 years.

Every man has been followed for at least seven years, said Dr Barnett Kramer, a study co-author at the National Institutes of Health.

By seven years, the death rate was 13 per cent lower for the unscreened group.

The European study saw no benefit of screening in the first seven years of follow-up.

Screening is not only an issue in prostate cancer. If the European study is correct, mammography has about the same benefit as the PSA test, said Dr Michael B. Barry, a prostate cancer researcher at Massachusetts General Hospital.

But prostate cancers are often less dangerous than breast cancers, so screening and subsequent therapy can result in more harm.

With mammography, about 10 women receive a diagnosis and needless treatment for breast cancer to prevent one death. With both cancers, researchers say they badly need a way to distinguish tumours that would be deadly without treatment from those that would not.

When the American and European studies began, in the early 1990s, PSA testing was well under way in the United States, and many expected that the screening test would make the prostate cancer death rate plummet by 50 per cent or more.

Some thought that they would see fewer cancer deaths among screened men as quickly as five years.