Prostate test 'all but useless'
Researchers say men put at risk of impotence
Sarah Boseley, health editor
Saturday September 11, 2004
Thousands of men may have unnecessarily undergone an invasive operation to
remove their prostate, sometimes suffering impotence and incontinence as a
result, because of a screening test which was yesterday written off as all
The PSA test is a blood test that measures levels of prostate specific
antigen, a protein produced by the prostate gland. It will tell doctors that
a man has a prostate cancer, but scientists in the US said yesterday that in
many cases the man can live with the cancer and the treatment may be worse
than the cure.
"The PSA era is over," said researchers at Stanford University school of
medicine in their paper in the Journal of Urology.
The team studied prostate tissues collected over 20 years, from the time it
first became standard to remove prostates in response to high PSA levels.
Thomas Stamey, who led the research, said they concluded that the test
indicated nothing more than the size of the prostate gland. "Our study
raises a very serious question of whether a man should even use the PSA test
for prostate cancer screening any more," he said.
Professor Stamey said he had also come to believe that the PSA test was not
a useful predictor of the amount or severity of prostate cancer.
He said raised levels of the protein only reflected a condition known as
benign prostatic hyperplasia - a harmless increase in prostate size.
Tumours found 20 years ago were generally so large they generated PSA levels
high enough to provide a reasonably good measure of cancer severity. But he
said that, as screening became more commonplace, many cancers were being
caught earlier and were usually smaller, not generating sufficient PSA to be
a good indicator of severity.
He said prostate cancer was a disease all men got if they lived long enough
so, given the excuse to carry out a biopsy, doctors were most likely going
to find cancer.
Prof Stamey said the PSA was still useful in monitoring patients after
removing the prostate as an indicator of cancer that had spread to other
parts of the body.
"Our job now is to stop removing every man's prostate who has prostate
cancer," he said. "We originally thought we were doing the right thing, but
we are now figuring out how we went wrong. Some men need prostate treatment
but certainly not all of them."
There have been more doubts over the PSA test in the UK, with the result
that the NHS has opted to give men information to allow them to choose to
have it if they are concerned, rather than instituting a national screening
programme. But an increasing number of doctors are doing it.
Chris Hiley of the Prostate Cancer Charity said a PSA test that proved
positive was likely to lead to a biopsy, and since 80% of men in their 80s
and even 8% of men in their 20s had prostate cancer, it was quite likely
that cancer would be detected. Men without symptoms who chose to have a test
in the first place were probably then more likely to opt for surgery rather
than the "watchful waiting" that some experts advocate.
"The intuitively obvious thing is that if you can get in and take the
prostate out, things will be fine and dandy, but large numbers of men will
be having operations they don't need," said Dr Hiley. Some will be impotent
and incontinent because of the nerves that are severed to remove the
prostate and any cancerous tissue.
No other test will detect a cancer in a man without symptoms, and some of
those with symptoms will be inoperable. Some 10,000 men die of prostate
cancer each year.