Systematic sextant biopsies in the prediction of extracapsular extension at radical prostatectomy.

OBJECTIVES

To evaluate the clinical utility of transrectal ultrasound-guided systematic sextant needle biopsies in the prediction of extracapsular extension (ECE) at radical prostatectomy.

METHODS

A retrospective analysis of 104 men who underwent systematic biopsy and radical prostatectomy at our institution was performed. All patients underwent preoperative staging by transrectal ultrasound and transrectal ultrasound-guided systematic sextant biopsy. The presence of pathologic ECE was correlated to the number of positive core biopsies on each side of the prostate by chi-square analysis. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios (LRs) were calculated for both positive (two or three biopsies positive per side) and negative (no or one positive biopsy per side) test results.

RESULTS

Forty-two (20.2%) of 208 sides demonstrated evidence of ECE at radical prostatectomy. Chi-square analysis demonstrated a significant correlation between the number of positive biopsies and the presence of ECE at radical prostatectomy (P = 0.001). Overall, the finding of multiple positive core biopsies (two or three per side) had predictive value with regard to the presence of ECE (sensitivity 62%, specificity 77%, positive predictive value 40%, negative predictive value 89%). The corresponding LRs were 2.5 for a positive and 0.5 for a negative test result.

CONCLUSIONS

The probability of ECE at radical prostatectomy can be more accurately assessed preoperatively by the combined use of transrectal ultrasound and systematic sextant needle biopsies.