Screening For Prostate Cancer Does Not Reduce Number Of Deaths

Screening men for prostate cancer appears to have no significant impact on prostate cancer mortality, Swedish researchers reported in the BMJ (British Medical Journal).

Screening for prostate cancer is common throughout most of the world, however, experts continue to disagree on whether their alleged life-protecting benefits are outweighed by overdiagnosis and unnecessary treatment.

Researchers from the Karolinska Institute examined a trial involving 9,026 males aged 50-59 years from Sweden's National Population Register.

1,494 of them were selected at random for prostate screening every year from 1987 to 1996. The remainder were controls (7,532 men).

The first two screenings only involved a digital rectal exam. From 1993 the screening involved both a digital rectal exam and a PSA (prostate specific antigen) test. In 1996, the fourth screening, only males up to the age of 69 years were invited.

The investigators included all the participants diagnosed with cancer up to December 31, 1999. They monitored survival rates until December 31, 2008.
5.7% (85) men were diagnosed with prostate cancer in the screened group and 3.9% (292) in the control group. Tumors were small and more frequently localized in the screened group.

The authors report that their analysis revealed no significantly longer survival or overall survival among the screened men with prostate cancer versus the control group.

A BMJ communiqué wrote:

"And while screening and treating men with detected tumours might reduce deaths specifically from prostate cancer by up to a third (at best), this would be at considerable risk of worrying overdetection and unpleasant or harmful overtreatment. Indeed, a previous trial found that to prevent one death from prostate cancer, 1,410 men would need to be screened and 48 treated. "
Before being screened, patients should be told about the risk of treatment, plus the anxiety and worry resulting from false-positive test results, the authors believe.

They add that future screenings should discriminate between indolent (slow growing) tumors and high risk ones. Less aggressive treatment should be the norm for indolent tumors. The aim should not be to simply seek to optimize the sensitivity of diagnostic tests.

The researchers concluded:

"After 20 years of follow-up, the rate of death from prostate cancer did not differ significantly between men in the screening group and those in the control group."
Other studies have been carried out on prostate cancer screening, but this is the first one with a 20-year follow-up, the authors added. It is only with a long follow-up that definite conclusions regarding screening can be drawn.


Source: Medical News Today, 1 April 2011
Author: Christian Nordqvist