PSA Levels Becoming Less Predictive

Modern biopsy techniques appear to have made Prostate Specific Antigen (PSA) testing less useful in men with a normal digital rectal exam. PSA testing has been commonly used to help physicians detect prostate cancer. Although the test was not entirely specific, it did provide clues for further diagnostic testing, such as prostate biopsy.

PSA levels less useful Doctors Douglas Scherr, Michael Schwartz and colleagues at the New York Presbyterian Hospital of the Weill Medical College of Cornell University, in New York City, performed a retrospective analysis of prostate biopsies at their hospital between 1993 and 2005. Data made up of 1,607 procedures, was then divided into three groups according to the year they were performed, 1993-1997, 1998-2001 and 2002-2005.

Each study group was then analyzed for the number of biopsies, number of positive biopsies, number of biopsy samples collected, prostate volume, PSA level prior to biopsy, and patient’s age. They foud that while the number of biopsies, number of positive biopsies and patient’s age did not change significantly between the groups; there was a decrease in median PSA level in men undergoing biopsy and an increase in the number of samples collected during the procedure. They also noted an increase in the number of patients undergoing biopsy with PSA elvels between 2.5 and 3.99 ng/mL. According to the American Cancer Society, PSA level >4 ng/mL strongly indicative of prostate cancer, however in 15% of cases, cancer is found with PSA levels below 4 ng/mL.

Positive biopsy rate in those with PSA level 2.0-3.99 ng/mL was found to be the same or higher than in men with higher PSA levels. The investigators determined that a positive correlation between PSA level and positive biopsy findings, no longer exists. In other words, high PSA levels may not necessarily indicate prostate cancer, while low levels may not necessarily mean that the patient is free of the disease.

Source: Wiley-Blackwell via EurekAlert!

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