NEW YORK, April 19, 2011 /PRNewswire/ -- According to a research from Northwestern Medicine, a new PSA (prostate-specific antigen) screening test for prostate cancer can more accurately identify aggressive forms of the disease and substantially reduce false positives, as compared to the two methods currently available. "This discovery is especially significant for men over 50 whose PSA levels put them in a 'gray zone,' where a biopsy may not be needed," said Dr. David B. Samadi, a prostate cancer screening, prostate cancer treatment, robotic surgery, and prostate cancer surgery expert. Dr. Samadi is also Vice Chairman, Department of Urology, and Chief of Robotics and Minimally Invasive Surgery at The Mount Sinai Medical Center in New York City.
The new screening method, Prostate Heath Index, compares blood levels of three types of PSA, which can better differentiate between elevated PSA and other benign contributing factors. Elevated PSA levels may indicate the presence of prostate cancer but may also be caused by inflammation or enlargement of the prostate gland, or other conditions. It is this "gray area" that can result in unnecessary biopsies or prostate cancer treatment options.
"The PSA test has long been the standard test for prostate cancer, but has also been controversial in failing to detect aggressive cancers from slow-growing ones that would not have been life-threatening," said Dr. Samadi, a urologic oncologist. "But it was the only marker we had, which is why I would combine the PSA results with Gleason and digital rectal exam scores to make an appropriate prostate cancer diagnosis – one method alone is never enough."
The study, which will appear in the May issue of the Journal of Urology, was led by Northwestern's Dr. William J. Catalona, the pioneer of the standard PSA test. It followed 900 men who had had normal prostate exams and compared the accuracy of the Prostate Health Index to the standard PSA. It also compared another test that measures the ratio between total PSA and a subtype called free PSA. The new screening method, also called the Pro-PSA test, more accurately detected cancer, particularly the aggressive forms, in men over 50 with dubious total PSA levels. It was most useful in patients with a normal prostate exam and a PSA level between 2 to 10. This range is considered the diagnostic "gray zone."
The new Prostate Health Index, or Pro-PSA test, was recently approved for commercial use in Europe. Currently, the FDA is currently reviewing the study data, which was supported by Beckman Coulter, Inc., a biomedical test developer and manufacturer. It could very well be approved for use in the United States in the near future.
"The Prostate Health Index can isolate the fast-growing prostate cancers and reduce the amount of false positives than other commercially available tests," said Dr. Samadi, "However, it's important to note that although the combination of the three tests outperformed any other single screening methods, it is not a perfect predictor of prostate cancer risk."