Proteins May Help Spot Prostate Cancer

WASHINGTON —  Researchers say they have found protein markers in a blood test that can be used to eliminate unneeded biopsies by sharpening the diagnosis of prostate cancer, the second deadliest form of cancer among American men.

In a study appearing this week in the Journal of the National Cancer Institute, researchers report that they may eventually be able to determine to a high degree of accuracy if a man has prostate cancer by testing a pattern of protein traces found in a single drop of blood.

“With further study, this has the potential to revolutionize the diagnosis and treatment of prostate cancer,” said Dr. David Ornstein, a prostate cancer specialist at the University of North Carolina in Chapel Hill who co-wrote the study. “This could help significantly reduce unnecessary biopsies.”

Men older than 50 are currently being screened routinely for prostate abnormalities with a blood test for the prostate specific antigen, or PSA. In most practices, men with PSA readings between 4 and 10 are routinely biopsied to determine if they have prostate cancer.

And yet, an estimated 70% to 80% of men with abnormal PSAs don’t have cancer but a benign condition that prompts the midrange PSA reading.

“The critical clinical question in prostate cancer is who should get biopsies when their PSA is in this intermediate range,” said Emanuel Petricoin, a researcher at the Food and Drug Administration and the first author of the study. Thousands of men have biopsies that would not be needed if doctors could determine with high accuracy from a blood test whether cancer was present, he said.

Using a system that precisely measures a pattern of proteins in the blood could be that test, Petricoin said.