CHICAGO -- There's more fuel for the debate over whether men should be screened for prostate cancer.

A small research study -- involving just 1,000 men -- found that two widely used tests for prostate cancer failed to save lives.

The study may offer a preview of what lies ahead in a few years, when the results of two large studies of prostate cancer screening appear.

Researchers looked at two screening tests that are performed millions of times a year in the United States. One is a blood test that measures prostate-specific antigen, or PSA. The other is a digital rectal exam.

PSA, a protein produced in the prostate, is found in the blood of healthy men. Prostate cancer often increases PSA levels in the blood, but a similar increase can be caused by other infections.

In the nine-year study, researchers compared the medical records of a group of men who died from prostate cancer to a group of living men. They found that the same fraction of men in both groups had received screening with the PSA test.

"This study suggests that screening was not effective," said Dr. John Concato, a researcher at Yale School of Medicine. "If screening worked, men who died would have had less testing than those who lived."

Concato and his team also determined that digital rectal examinations along with PSA did not improve survival.

The study is published in Monday's issue of the Archives of Internal Medicine.

"Unfortunately, screening tests can sometimes find cancer, even at early stages, but not prolong survival," Concato said.

He said that, for now, doctors should tell men that screening tests for prostate cancer aren't perfect -- and that men should decide for themselves whether to get screened.

• Study Abstract