Abstract
Objective:
The objective was to provide urologists with a simple basis for optimizing the number of prostate biopsy cores that should be taken.
Methods:
The records of 1024 patients who had undergone transrectal ultrasound-guided biopsies were reviewed. The prostate volume was divided by the number of biopsies to obtain the volume/biopsy ratio (VBR). Univariate and multivariate analyses were performed to determine the best predictors for positive biopsies.
Results:
The analysis included 939 patients who had prostatic-specific antigen <20 ng/mL. The significant independent variables for positive biopsies were age, prostatic-specific antigen, and prostate volume and VBR (p < 0.001). VBR had the strongest correlation coefficient out of all significant variables. Stepwise analysis showed a consistent increase in cancer detection rates as VBR was decreased. The detection rates for VBRs of 2, 3, and 4 were 59%, 53%, and 50%, respectively. The detection rates dropped sharply to 42% and 30% for VBRs of 5 and 6, respectively. Cancers diagnosed with low VBRs were similar to those diagnosed with high VBRs in regard to Gleason scores and percentages of cancer in the prostatectomy specimens.
Conclusion:
Using VBR of 4 maintains high cancer detection rates without taking an excessive number of biopsy specimens. This is a simple and easy-to-remember method.