WEDNESDAY, June 30 (HealthDay News) -- Adding to the ongoing
debate on the usefulness of the prostate-specific antigen (PSA)
blood test for prostate cancer, new research from Sweden finds the
screen cuts lives lost to the disease by almost half.
The argument over whether PSA screening saves men's lives or
merely leads to the overdiagnosis of very slow-growing cancers
(with attendant worry and overtreatment) has bedeviled the medical
world for years.
According to recently revised guidelines from the American
Cancer Society, men at average risk for prostate cancer should
discuss the PSA test with their doctor, starting at age 50. For men
at high risk for the disease -- blacks and men who have a father,
brother or son found to have prostate cancer at an early age
(before 65) -- that discussion should start at age 45.
"Because prostate cancer grows slowly, those men without symptoms of prostate cancer who do not have a 10-year life expectancy should not be offered testing since they are not likely to benefit," the society notes on its Web site.
Ambivalence over the test hasn't been confined to the United
"In Europe, we have been reluctant to recommend that all men get PSA testing as we have felt that there has been a lack of knowledge," agreed lead researcher Dr. Jonas Hugosson, a professor of urology at the University of Gothenburg.
However, he believes that with the results of the new 14-year
study, "it feels ethically difficult not at least to inform all men
over the age of 50 about PSA and its possibilities. Personally, I
would recommend my friends check their PSA," Hugosson added.
The report is published in the June 30 online edition of
The Lancet Oncology.
For the still-ongoing study, Hugosson randomly assigned some
20,000 men to either PSA screening once every two years or no
screening. The men were between 50 and 65 at the start of the
Men whose PSA levels were above normal were offered more tests,
such as a digital rectal exam and prostate biopsies.
Over 14 years of follow-up, deaths from prostate cancer dropped
by 44 percent among the screened men, compared with unscreened men,
the researchers found. Overall, 44 of the men who had PSA testing
died from prostate cancer, compared to 78 men who had not had been
Among screened men, 11.4 percent were diagnosed with prostate
cancer, compared with 7.2 percent of unscreened men. Of the men in
the screened group diagnosed with prostate cancer, nearly 79
percent were diagnosed because they took part in the study, the
In addition, men in the screened group were more likely to have
their cancer diagnosed while it was in an early stage. In the
screened group, 46 men were diagnosed with advanced cancer,
compared with 87 men in the unscreened group, Hugosson's team
"Our study has a longer follow-up than previous studies, but shows that in those men invited [to the study], the risk of dying is only half of that in the control group. In men younger than 60 at study entry, the effect was even more pronounced -- only one-quarter of expected deaths occurred," Hugosson said.
Moreover, the risk of over-diagnosis was less than previously
thought, with just 12 men needed to be diagnosed to save one life.
However, since the benefit of PSA screening requires at least 10
years to be borne out, it still seems questionable to test PSA for
men over 70, the researchers noted.
Dr. David E. Neal, a professor of surgical oncology at the
University of Cambridge in the U.K. and author of an accompanying
editorial, believes that, "PSA testing detects prostate cancer
early in its natural history when it causes no symptoms. By doing
so, it can save the lives of some men who would otherwise have died
of the disease."
This study adds to previous evidence that PSA testing and
screening for prostate cancer saves lives, he said. Still, the PSA
test remains "a blunt instrument," when it comes to determining the
aggressiveness of a particular tumor, Neal said. "We need better
tests that identify more accurately those men destined to develop
problems in the future from this disease," he said.
In the United States, PSA testing remains a routine part of most
physical exams, according to Dr. Nelson Neal Stone, a professor of
urology and radiation oncology at the Mount Sinai School of
Medicine in New York City.
"I would say 70 to 80 percent of physicians now order a PSA test," he said. "So it is more or less the standard to care in America to get a PSA done."
Stone noted that screening detects a lot of early cancers, which
do not need to be treated. "When we see patients with low-risk
disease we don't treat them, we observe them," he said.
"Younger men benefit most from screening, because they have the greatest risk of dying," Stone said. "This study clearly supports PSA screening to prevent prostate cancer deaths."
Another expert, Dr. Anthony D'Amico, chief of radiation oncology
at Brigham and Women's Hospital in Boston, added that "people in
good health will benefit from [PSA] screening, but people in poor
health may not benefit at all." That's because if their prostate
tumor is not aggressive they are more likely to die from the other,
more serious conditions, he explained.
For more information on prostate cancer, visit the
American Cancer Society.