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Prostate cancer screening does save lives, although screening may have to be done for many years in order to provide a benefit, according to a new study.
In the study, men who were screened for prostate cancer using the prostate-specific antigen (PSA) test were about 30 percent less likely to die from prostate cancer over an 11-year period compared with men who were not screened.
The findings agree with those of an earlier analysis of this same group of men. Those findings, published after the men had been followed for nine years, also showed a reduced risk of death from prostate cancer in those who underwent PSA testing.
"Doctors who discuss the possibility of screening (PSA testing) with their patients can now state with more certainty that screening reduces the chance of death from prostate cancer," said study researcher Dr. Fritz Schröder, a urologist at the Erasmus University Medical Center in The Netherlands.
The findings contradict those of a study published in January, which found yearly screening for prostate does not save lives.
In addition, PSA testing comes with risks. It finds cancers that would never have been diagnosed without screening, meaning the cancers would not have gone on to cause significant health problems for patients.
The researchers estimated about half of the cancers detected in their study fell into this category. Such overdiagnosis can result in unnecessary biopsies and treatments, which come with a risk of erectile dysfunction and loss of urinary control.
Many experts believe these harms can be reduced,after a screening test is done, by following an approach known as active surveillance. In active surveillance, men diagnosed with low-risk prostate cancer are closely monitored, and treated only if their cancer progresses to a more aggressive form.
"Too often, men…when found they have prostate cancer, immediately think they're at risk for dying and need treatment," said Dr. Mark Soloway, a professor in the department of urology at the University of Miami Miller School of Medicine. But it's becoming increasingly clear that for low-risk prostate cancers, "probably the best thing is to do nothing but observation," Soloway said.
Preventing prostate cancer death
The new findings are based on 162,388 men from seven European countries between ages 55 and 69. About half were invited to receive prostate cancer screening, and half were not offered screening. Most men in the screening group underwent a PSA test every four years, except those in Sweden, who received the test every two years.
During the study, 6,963 men in the screening group (9.6 percent) were diagnosed with prostate cancer compared with 5,396 men (6.0 percent) in the group not offered screening.
There were 299 deaths from prostate cancer in the screening group, compared with 462 deaths from prostate cancer in the group not offered screening.
That means that, overall, prostate cancer screening reduced men's risk of dying from prostate cancer by 29 percent, after the researchers took into account those who did not comply with the study protocol.
To prevent one death from prostate cancer over 11 years, 1,055 men need to be screened and 37 cancers would need to be detected, the researchers said.
The risk of death from any cause was similar in the two groups: there were 18.2 deaths per 1,000 men per year in the screening group, compared with 18.5 deaths per 1,000 men per year in the group not offered screening.
Older men may not benefit
"There will continue to be debate regarding the overall benefit of screenings," said Dr. Manish Vira, of the Arthur Smith Institute for Urology, part of the North Shore-Long Island Jewish Health System in New Hyde Park, N.Y., who was not involved in the study.
The study published in January, which showed no reduction in deaths from screening, involved about 76,000 men who were followed for 13 years, and screening tests that were done yearly.
Together, the research suggests screening should be done every two years, rather than every year in order to provide a benefit, Vira said.
In addition, benefits of screening don't show up for at least 10 years, Vira said.
"Therefore, older men with significant co-morbidities are unlikely to benefit from screening, and in fact, may experience significant harm," from biopsies and treatment of prostate cancer, Vira said.
Soloway said men can go ahead and get their PSA levels tested, but they should be informed about what the results mean. Just as high cholesterol levels don't necessarily mean you need to go on cholesterol-lowering drugs, a high PSA level does not necessarily mean a man needs prostate cancer treatment, Soloway said.
The study will be published tomorrow (March 15) in the New England Journal of Medicine.
Pass it on: Prostate cancer screening conducted over 11 years may reduce the risk of death from the disease.