Biopsy Techniques Make PSA Test Less Useful

The study suggests that improved biopsy techniques make PSA less useful in prostate cancer screening. Douglas Scherr, MD, Michael Schwartz, MD, and colleagues at the New York Presbyterian Hospital of the Weill Medical College of Cornell University, in New York City, set out to assess whether changes in prostate biopsy practices might have changed the predictive value of PSA tests.

The researchers performed a retrospective analysis of all prostate biopsies performed at their institution between 1993 and 2005, finding 1,607 that satisfied their inclusion and exclusion criteria. Scherr and his team divided patients into three groups based on when they received their biopsies: 1993-1997, 1998-2001, and 2002-2005.

They examined each group for the number of biopsies performed, the number of positive biopsies, patient age, most recent PSA prior to biopsy, prostate volume, and number of biopsy samples taken. With these data in hand, they assessed potential correlations between PSA levels and positive biopsy rate.

The investigators found that the number of biopsies performed, the percentage of positive biopsies, and patient ages did not change significantly over time. However, there was a significant decrease in the median PSA level in patients undergoing biopsy and an increase in the median number of samples taken at the time of biopsy. Also, fewer biopsies were performed for the indication of a suspicious digital rectal exam and there was an increase in the percentage of patients undergoing biopsy for PSA readings between 2.5 and 3.99 ng/ml.; Source: Wiley-Blackwell