Researchers: Test can predict prostate cancer deaths

Using a routine blood test for prostate cancer in a new way, scientists in Manhattan say they can predict with a high degree of accuracy which men could die from the disease within 25 years of a benchmark screening at age 60.

Researchers at Memorial Sloan-Kettering Cancer Center, who collaborated with a team of scientists in Sweden, found they could use the prostate specific antigen test - the PSA - as an accurate predictor of a man's fate regarding prostate cancer over a quarter century. Those men who had a low value PSA, scientists said, could avoid screening from age 60 onward. Men who had a high value, they said, would need to continue the annual test.

PSA testing has been recommended in the United States as part of routine preventive care starting at age 50 for more than two decades. The test has become a major public health tool aimed at spotting cancer in early stages. But in recent years the PSA has come under fire because of its potential for false positives and other problems.

Reporting in Wednesday's online edition of the British Medical Journal, Dr. Andrew Vickers of Memorial Sloan-Kettering and colleagues at Lund University in Sweden proposed a paradigm shift: moving away from the PSA's chief use as a screening tool and using it more aggressively to forecast risk.

"We're taking an old test and looking at it in a new way," Vickers said Tuesday. "What we are saying is this: At 60, half all men with a PSA of 1.0 or lower are at very low risk of prostate cancer and it is difficult to see how they would benefit from further screening. But 90 percent of men who die from prostate cancer have a reading of 2.0 or higher and should continue screening."

Vickers and his team based their conclusions on blood samples of Swedish men participating in the Malmö Preventive Project. Scientists analyzed blood samples collected between 1981 and 1982 from 1,167 men born in 1921.

Those samples were then compared against cancer registries through the end of 2006, at which time the men had either died or reached their 85th birthday. There were 43 cases of advanced prostate cancer and 35 deaths from the disease. The advanced cases and deaths were concentrated in the group of men whose PSA values were 2.0 or higher at age 60.

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Doctors unconnected with the research say not only would they like to see additional research, they also don't want to see an end to routine PSAs.

"This study may have some great science behind it, but it is far from being the be-all and end-all," said Dr. Howard Adler, medical director of the prostate care program and associate professor of clinical urology at Stony Brook University Medical Center.

Adler noted one of the largest prostate cancer research projects ever conducted found cancers sometimes lurked in men whose PSA values were low.

Dr. Richard Ashley of the Smith Institute of Urology at the North Shore-LIJ Health System, said the study opens yet another round of discussion on the value of routine prostate cancer screening. "This study is about a shift in thinking. It asks, Do you have to test everyone?"

Ashley also called for further research based on a diverse American population, which includes African-American men, who are at particularly elevated risk for prostate cancer. "This is a Swedish population," he said of the study "and I don't think it represents what we see in America."